This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------ Here find some excellent tips for machining or working with various plastics. Machining plastic may need machine speeds and cutters/tools and techniques significantly different from those used for metals, woods, and other common materials. Hopefully there are some tips in the following conversations that will help you. SAFETY HAZARDS. Please note carefully that plastics and related materials mentioned in this file may have increased health and safety hazards that will require special safety precautions and protective equipment and safety measures beyond your usual shop practices, and far beyond whatever may be written here. Be safe and consult OSHA [or the equivalent health and safety government organization in your state or country] for laws, regulations, rules and recommendations for what you are about to do, and follow them. Always consider leaving dangerous materials and procedures to competent professional companies; contract out that unsafe work and only do the totally safe bits yourself. You are engaging in a hobby and owe it to yourself and your family to be prudent, careful, healthy and long lived. If you got to this file directly from my HOME PAGE, return there by using your browser's back button. BUT if you came to this file as the result of a web search engine, see many additional files on my home page Machining and Metalworking at Home http://www.janellestudio.com/metal/index.html SAFETY WARNING BEWARE: DO NOT ASSUME that any subject matter or procedure or process is safe or correct or appropriate just because it was mentioned in a news/user group or was included in these files or on this site or on any other web site or was published in a magazine or book or video. Working with metals and machinery and chemicals and electrical equipment is inherently dangerous. Wear safety devices and clothing as appropriate. Remove watches, rings, and jewellery -- and secure or remove loose clothing -- before operating any machine. Read, understand and follow the latest operating procedures and safety instructions provided by the manufacturer of your machine or tool or product. 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(c) Copyright 2003 - 2016 Machining and Metalworking at Home The form of the collected work in this text file (including editing, additions, and notes) is copyrighted and this file is not to be reproduced by any means, including electronic, without written permission except for strictly personal use. ======================================================================== Date: Thu, 03 May 2001 20:12:53 -0000 From: ptolemyx~xxbellsouth.net Subject: Plastic Gears Hi- Does anyone h experience to share regarding milling plastic gears in the 0.5" - 2" range (1 - 5 cm ;)? Has anyone used either nylon or Delrin? Thanks, Neil ------- Date: Thu, 03 May 2001 20:41:23 -0000 From: n2562001x~xxyahoo.com Subject: Re: Plastic Gears Neil: Standard or single point cutters will work fine. On nylon and other soft plastic use a backer behind the blank to get a clean cut. You may also need to cut a little deeper to get proper tooth fit. depending on the application you may also want to use a little larger tooth profile for strength. Jerry Kieffer ------- Date: Thu, 3 May 2001 16:04:11 -0700 From: "Keith Yundt" Subject: Re: Plastic Gears Neil, I have cut some bevel gears out of delrin to replace some G scale steam loco gears for my neighbour. I have used a flycutter for mine, and the only thing I would add to what Jerry said is that delrin seems to "stretch" alot. I drilled the gear out to fit a shaft, using my lathe, and when I went to put it on the shaft I was amazed to find that it was very(too) tight. The only thing I could think of was that it "stretched" during the drilling; maybe I was crowding it too much when I drilled it, I'm not sure. Otherwise, though, it cuts great and you should have no problems. Keith Yundt ------- Date: Fri, 04 May 2001 01:38:40 -0000 From: ptolemyx~xxbellsouth.net Subject: Re: Plastic Gears Thanks Jerry and Keith for the info. A website I visited mentioned the tendency of Delrin to stretch while being machined and then to relax. The context there was that holes drilled by reaming might have a slightly smaller than expected final diameter -- presumably having been temporarily deformed under pressure during cutting. I tend to budget some of the stock for experimentation -- I'll report any interesting results. Neil ------- Date: Thu, 3 May 2001 20:42:51 -0700 From: "Marcus & Eva" Subject: Re: Plastic Gears Hi Neil: Delrin is the material to use. It machines a lot better than nylon and has excellent strength. It also has a low coefficient of friction. Many molded plastic gears are Delrin. Cheers Marcus ------- Date: Mon, 11 Jun 2001 17:30:55 -0500 (CDT) From: Tom Benedict Subject: Re: Re: Delrin On Mon, 11 Jun 2001, Ken Jenkins wrote: > I agree entirely. I really like the material in terms of end results > and the many different ways you can use it but it is kinda nasty > /stringy to turn. I haven't experimented much with different tool > profiles or angles maybe some adjustment in that direction would make > working with it easier I don't know. I've cut Delrin, Nylon, UHMW, PVC, and a couple of other plastics. Except for acrylics, just about all of them are stringmeisters. Some acrylics have the opposite problem, and crumble under the tool, making for nasty dust. (I'll take the stringies, personally.) Tom ------- From: David Beierl Date: Thu Aug 2, 2001 9:06 am Subject: Re: [atlas_craftsman] acetal At 07:55 AM 8/2/2001, Ron Odum wrote: >Can someone please tell me a little about an alloy (?) know by the >name or Acetal or Delrin? http://americanplastics.net/page90.html Do google on "delrin properties" you'll get plenty. david David Beierl - Providence, RI USA 6 (or 3)" Atlas lathe ca. 1941 ------- From: helpx~xx4... Date: Thu Aug 2, 2001 9:23 am Subject: Re: [atlas_craftsman] acetal Delrin is a trade name for acetyl- it cuts well turns well, but it is somewhat brittle, and can crack and chip without too much effort. It is highly used in electrical connector work, and is a cood insulator for electrodes, and current carrying wires. It is available in colors and has good chemical resistance. Black is good at duplicating small injection molded pieces which can no longer be found. Regards, George O'Connor ------- From: tadici283x~xxc... Date: Thu Aug 2, 2001 9:45 am Subject: Re: [atlas_craftsman] acetal mattking... writes: > >Can someone please tell me a little about an alloy (?) know by the > >name or Acetal or Delrin? Tough stuff, takes a lot of abuse, machines well with sharp tools no great odor like some other plastics, can be formed into nearly anything. I can't think of anything out of the ordinary, does make better gears than plastic. Chris of Bradenton FL ------- From: "Mac Goekler" Date: Thu Aug 2, 2001 4:33 pm Subject: Re: [atlas_craftsman] acetal Hi Rod, Delrin (DuPont) or Celcon (Celanese) are plastics (Acetal polymer) that have certain self-lubricating properties (no fun to mold -- mold surface gets a wax like, para-formaldehyde coating). Great for gears, bushings, bearings, etc. You will need a sharp tool to machine. As plastics go -- it is much like nylon -- except for the lubricating issue. Have fun, Mac from Ohio ------- From: cravdraa... Date: Sat Aug 4, 2001 6:54 am Subject: Re: acetal One of the favorite machinists there is S .K . Grimes, a machinist for large format photographers, he uses Delrin to make new lenscaps for old LF lenses: http://www.skgrimes.com/ Alex ------- From: catboat15... Date: Wed Aug 15, 2001 5:50 pm Subject: Re: [atlas_craftsman] turning Plexiglas rod Scottx~xxB... writes: > ... does anyone on this list have any experience I have turned a bit of PVC pipe to make various things for myself. Machines quite nicely. But to machine plexiglass and similar the problem is two parts. One is the heat of cutting can melt the plastic, Two the chips stick to everything, tool, work piece, yourself. Keep everything cool and machining is no problem. Use plenty of rake and clearance on the tools. Finished work can be polished with toothpaste or you can use a solvent to get rid of the "frosted" appearance of the plastic after cutting. John Meacham High Desert of California, Palmdale, Littlerock. ------- From: Jon Elson Date: Wed Aug 15, 2001 10:49 pm Subject: Re: [atlas_craftsman] turning Plexiglas rod scott Bonelli wrote: > I'm new to this list.. I joined because it looked like a good place > to start learning about lathe work. I am interested in learning how > to turn plastic rod, as well as aluminum. I assume that turning > Plexiglas rod is similar to working with metal.. Only in the most general terms. Plexiglas (Rohm&Haas trademark for acrylic) is brittle, produces immense heat when cut, and tends to gum up around cutting tools. So, there are a number of tricks to cut it without major problems. > I thought I would pick a few brains before purchasing a machine. > Does anyone on this list have any experience working with plastics? > .. is anyone on this list located in the New England area? > I'm located in Rhode Island, and am trying to hook up with someone > who knows what they are doing, before I jump into this. I've done a number of plastic parts over the years, acrylic, Teflon, PVC, etc. They are all a little different, but the problem of the plastic getting hot enough to melt and then gumming up on the cutter is nearly universal. I'm in St. Louis, so you can't drop by for a chat too easily, but I'll be glad to share what I know. Jon ------- Date: Sat, 15 Sep 2001 18:05:58 -0400 From: "Mac Goekler" Subject: Re: PVC turning question From: >>I've been turning 3" solid PVC on the Sherline with riser blocks. This material lets me take heavy cuts at a fast feed with the highest speed. The swarf streaming onto me is very hot. Is there any danger of this stuff catching fire or should I slow things down? I'm not using cutting fluid. Todd << Hi Todd, PVC will not burn. If you get it too hot it will degrade into HCL gas (nasty stuff). Normally, soapy water is used as a lub. Good Luck, Mac from OHIO ------- Date: Sat, 15 Sep 2001 21:38:54 -0400 From: "Mac Goekler" Subject: Re: PVC turning question > Thanks. If it starts turning into HCL will I be able to smell it? Will > water rust my HSS and carbide tools? Todd Hi Todd, Yes, you will notice the HCL (hydrochloric acid)-- it will drive you from the room. I've been asked if it was poisonous -- my response is that you will have left (or been driven) from the premises long before it'll do you any damage. It will corrode almost any metal (not gold). I've taken deep cuts on rigid PVC with not real problem. Soapy water will rust your tools if left in it -- but not if you dry them off promptly. PVC tooling requires lots of relief and rake. Carbide will certainly last longer than HSS. Good Luck, Mac from Ohio ------- Date: Sun, 11 Nov 2001 10:43:19 -0600 From: Richard Meredith Subject: Re: Turning skate wheels LADDERBARx~xxaol.com wrote: >> This is what I'm trying to do, Turn wheels from a set of roller blades From 82 mm to 76 mm. The reason is my wheels are bigger than my sons and when you skate you wear out the wheels. So instead of throwing my worn ones away I want to make them fit my sons. (am I cheap or what)LOL. The wheels are harder rubber 84 duraumiter I tried to cut them with a very sharp H.S.S. bit and a carbide one. Didn't work. So I started to file them -- very time consuming. Any suggestions appreciated. << Hello Mike: Having machined both hard rubber, and soft plastics on a lathe, I have found that a very, very, positive rake tool, and lower surface footage works best. You need to slice the material off much like wood turning, not scrape off as really more the effect on soft material with most metal working tools. Keeping the surface footage down helps control heat buildup on the tool. Most larger cities have at least one automotive tire dealer with a tire lathe. (Yes they do turn tires to true them up!) You might want to call around and see which dealer has one, and pay them a visit. The scale of the tooling is wrong, but it might give you some ideas. Good Luck, Rich ------- Date: Sun, 11 Nov 2001 10:00:41 -0600 From: Bill Aycock Subject: Re: Turning skate wheels In most cases of trying to cut rubber, the problem is the friction. The problem is - it sticks- then distorts, pulling the material into the blade. Most machining of rubber-like products is helped by lubricating the cut area with water. If this is not possible- try using a disc sander on the rotating wheel. Hope this helps- Bill ------- Date: Sun, 11 Nov 2001 08:15:51 -0800 (PST) From: Don Smith Subject: Re: Turning skate wheels Mike, I just machined a urethane skate wheel a few days ago and had no problem at all...using a carbide bit with a narrow rounded tip. As far as machining the ones you have, maybe it would be worth a try to put them in the freezer for awhile before machining. Regards, Don Smith ------- Date: Wed, 27 Mar 2002 19:34:50 -0000 From: "rpm2290028" Subject: Re: Turcite, or Moglice In atlas_craftsmanx~xxy..., "n5fee" wrote: > I have seen this epoxy mentioned a couple of times recently on this > list. I have searched the archives and see it mentioned in passing > in a couple of other messages, but I cannot find information about it > by searching the web. Who makes these products and where can > information about it be found? Thanks, Dallas Shell, 6 in Atlas Dear Dallas, I do a lot of work in plastics, so am familiar with many different types. Turcite is not an epoxy, it's a specially made plastic for bearings that is similar to acetal/delrin in machining chatacteristics. It's bearing properties are somewhat like graphite impregnated nylon, only more efficient. Unless you really have to, you should try to design/work around Turcite since it's fantastically expensive. I recently bought a foot length of 3/4" rod for $14.00. The thinner sections are three or four times that, I believe because it is more difficult to make in that size. ------- Date: Wed, 6 Feb 2002 18:45:35 -0600 (CST) From: Tom Benedict Subject: Re: Boring a water jacket On Wed, 6 Feb 2002 ajkdfwx~xxaol.com wrote: > I'm trying to make a water cooling jacket for an Astro Flight motors > for my scale boat. It will be about 2" long. I feel the best way to > seal this is with rubber O-rings at each end. I have been fooling > around (without much success) with PVC pipe as I have not found any > thick walled aluminum tube as yet. Check if there are any local industrial metal suppliers. They can usually get whatever you need (at cost). Better yet, check the local scrap yards and see what you can find. > The OD of the motor is 1.315 and I'm trying to use sched. 80 PVC (it's > thicker) with an OD of 1.75. Has anyone out there tried to bore PVC? Yep! > What are the best speeds for this on the Taig? The big problem I ran into when I was making PVC parts is that any kind of heat at the tool can melt the PVC. Rather than rig a pump coolant system for water, I opted for slow speeds and fast feeds. Nothing outrageous, but you're aiming to get the plastic out as a nice continuous strip. One more caution on that: If you get it going just right, the chip will shoot out to one side. Great! But it can very very easily catch on the chuck, cross-slide, whatever, and grab. If it looks like you're going to have grabby swarf, turn off the motor and clear it before taking the next cut. It's no fun when it grabs. Best advice is to chuck up some cheap PVC fittings you don't care about (like sched 40 caps, which are less than a buck apiece), and play with it. Try some different spindle speeds and feeds, using different tool geometries. You'll hit on a combo you like. > How do I go about boring it out and still leave enough on each end to > make a channel for the O-rings? Do I need a special type of boring bar? Shouldn't think so. Just design your part geometry in such a way that you've still got room for the o-ring. > Lots of questions ... any help will be greatly appreciated. No problem! PVC's pretty neat to turn. Just be sure the part doesn't leap out of your chuck jaws! It's a truckload more flexible than aluminum! Tom ------- Date: Mon, 22 Apr 2002 19:03:59 +0100 From: "Graham Knight" Subject: Re: machining acrylic I do quite a bit of work with acrylic, the secret is to use CAST acrylic not extruded, it machines much better but is more expensive. Most acrylic rod you will find is the cheaper extruded type which can be very difficult to machine; you should really try to find a supplier who stocks cast and knows the difference. If he doesn't know what it is then it's almost certainly extruded as they just stock the cheapest they can get, unless they are aware of a special need for cast material. Graham in London, England SAM35 & 1066 Raynes Park MAC Secretary http://website.lineone.net/~raynes.pk.mac/ ------- Date: Wed, 1 May 2002 11:50:10 -0400 From: "Daniel Munoz" Subject: machining / polishing Acrylic Last time I talked here about my experience in machining Acrylic, someone said that he had experience with it. Graham I think ? I'm searching a way to polish acrylic at final to restore the transparency. With a simple shape like a rod, I can manage it, with very fin sandpaper (grid 2000), and also some polishing compound applied with a cloth. But it is a long and fastidious process. When the shape is complicated, I have difficulties to restore the polish properly. Is there some tricks about this material one could share ? Thanks, daniel ------- Date: Wed, 01 May 2002 09:56:39 -0700 From: Craig Chamberlin Subject: Re: machining / polishing Acrylic Hi Daniel If I remember correctly, you can flash a torch (using a big tip) over the surface and it will clear up. Takes a little practice. Ciao, Craig ------- Date: Wed, 1 May 2002 18:00:17 +0100 From: "Graham Knight" Subject: Re: machining / polishing Acrylic None that I know of, I usually use a polishing compound like T-Cut to get the final scratches out. Most of my acrylic work gets a final finish of sprayed 2-pack acrylic lacquer, any minute scratches disappear completely once it's sprayed, but I don't know if you want to do that, or have the facilities to do it? Graham in London, England SAM35 & 1066 Raynes Park MAC Secretary http://website.lineone.net/~raynes.pk.mac/ ------- Date: Wed, 01 May 2002 10:29:31 -0700 From: Randy Gordon-Gilmore Subject: Re: machining / polishing Acrylic A fix used by modelers is to dip the clear parts (windshields etc.) in Future floor finish (full-strength), let the excess drain off and hang to dry. Future isn't a polish or wax, but is actually some kind of acrylic emulsion that dries glossy. A lot of people also airbrush it (again, full-strength) as a gloss clearcoat for their models. Best regards, Randy (who has not tried the dipping process--only read about it!) ------ Date: Wed, 1 May 2002 18:49:08 +0100 From: "Graham Knight" Subject: Re: machining / polishing Acrylic 2-pack acrylic is a lacquer/hardener system mostly used for automotive refinishing, it's very easy to get a good finish with it, much easier than the old cellulose paints. It does require the use of a decent mask, one rated for organic vapours, and proper ventilation, but it's not as hazardous as some materials. The brand I use is Mipa, or a more expensive one called Glasurit, both made in Europe I think. I don't know if either of these is available in Canada but you should be able to find something similar. Visit your local car repairer and ask, they may sell/give you a small amount. Randy's comment about floor polish reminded me that I have used Johnsons Klear for this purpose too, it works quite well when sprayed then polished, but it's probably not as durable as the 2-pack acrylic. Graham in London, England SAM35 & 1066 Raynes Park MAC Secretary http://website.lineone.net/~raynes.pk.mac/ ------- Date: Sat, 16 Nov 2002 17:17:42 -0000 From: "timgoldstein" Subject: Re: Delrin/Acetal--Best Milling RPM, Best Lubricant? In sherline..., "variousgroups" wrote: > Anybody have any advice about the best rpm to use for milling > Delrin/Acetal and is there a best lubricant to use? Delrin is easy. I have cut it dry, with a light spray of water based coolant from a mist cooler, and with flood coolant (water and cutting oil) in a spray bottle. All seemed to work just fine, but the surface finish may have been slightly nicer with either coolant. As far as speed goes I use about the same as aluminum (in other words crank it up) with about double the feed of aluminum. The stuff cuts like butter and if you go too slow the tool scuffs a lot and gets hot. Tim [Denver, CO] Sherline at Deep Discounts www.KTMarketing.com/Sherline ------- Date: Sat, 07 Dec 2002 21:39:23 -0800 From: "Scott A. Stephens" Subject: Teflon I plan to use Teflon in a project. But the Teflon will be part of a seal and I need a really smooth finish to make this work. So guru's, which is better for cutting Teflon??? HSS, or carbide???? ------- Date: Sun, 08 Dec 2002 01:08:30 -0500 From: RichD Subject: Re: Teflon Scott, Either one, as long as its ***SHARP***. Top rake may help as well. RichD ------- Date: Sun, 8 Dec 2002 14:00:50 -0500 From: "David Simmons" Subject: Re: Teflon Scott: Look at most Teflon's as if you are about to cut free machining aluminum. But make sure your tools are at peak. Very sharp!!! Also your RPM should be a little higher - and the cut depth should be fairly deep, even on the finish cut - Teflon defects badly. I have supplied my son - 12 now - with a fair amount of Teflon to give him a chance to understand his lathe and tools before he can damage anything. It is that easy to work with! Later, Dave S. ------- Date: Mon, 06 Jan 2003 17:52:48 -0000 From: "Paul Smith " Subject: Machining Solid Carbon Rods Does anyone have any experience in machining carbon/graphite rod? I saw some solid carbon rods on the glass-supply.com website and I was wondering if they would be suitable for a project that I am working on. Specifically I was wondering if standard tools (cutters, drill bits, cutoff tools, etc.) were suitable or if I would need something different. I guess my major concern is that the carbon may be too brittle and just shatter. Thanks, Paul ------- Date: Mon, 06 Jan 2003 12:00:07 -0600 From: Ron Roske Subject: Re: Machining Solid Carbon Rods Paul: Can't really help on the machinablity aspect, but their 1/4" rods are only $1.50. Your question may be answered best by getting one of those and writing the $1.50 off to R&D. I may do that myself, just out of curiosity. RonR ------- Date: Mon, 6 Jan 2003 12:12:01 -0600 From: "Nance, Tom" Subject: RE: Machining Solid Carbon Rods Hi Paul: The pistons for Jerry Howell's sterling engines use graphite rod. I have made 3 of them so far and have had no trouble with the graphite. Like you, I was at first concerned with how it would machine and approached that part of the construction with trepidation. It turned out that graphite is really nice to machine. It's some pretty tough stuff, although I was taking pretty shallow cuts cuz I didn't want to find out what its breaking point was. The only problem I can see with it is the mess it makes. Toward the end I was holding the shop vac up near the tool to try to suck up all the dust it was making. To answer your question, just about any tool will cut it - even your fingernail. It's is real easy to size because you can use sandpaper to cut it down quickly and then typing paper to bring it to final size. Just think of it as a huge pencil lead. It's really a joy to play with. Try it out. Tom Nance Corpus Christi, TX ------- Date: Mon, 06 Jan 2003 10:46:43 -0800 From: "Orrin B. Iseminger" Subject: Re: Machining Solid Carbon Rods I machine graphite, regularly, with no problems. I use a HSS tool and run the lathe at high speed. Graphite makes a mess and the binder is very abrasive, so I hold the vacuum cleaner suction next to the cutting tool, continuously. The binder will dull the tool, rapidly. You'll need to sharpen it much more often than you'd have to when cutting mild steel. I place cut-up file folder material between the graphite and chuck jaws. I just cut a strip that's long enough to wrap around the whole piece. So far, I've never broken any graphite when machining it. Orrin ------- Date: Tue, 07 Jan 2003 09:39:56 +1100 From: "Charlie Lear" Subject: Re: Machining Solid Carbon Rods Paul Smith" wrote: >Does anyone have any experience in machining carbon/graphite rod? Paul, in my youth I looked at buying a big old lathe that came with a contract to machine electrodes for a steel mill blast furnace. The tool used was a standard brass round nose - zero rake - and SFPM was about the same as for mild steel. Thats about as much as I can recall. I suggest you experiment with the same parameters - it'll only cost you grinding time for one end of an HSS blank and some scrap material. I also played with the rods contained in old D-size batteries - whether they are the same material these days I don't know. But the graphite is quite brittle and you should make a split bush to hold it, rather than straight in the 3-jaw. Set up a vacuum cleaner nozzle close to the action (trust me on this). Cheers Charlie (PS - my dad took one look at the condition of the workshop and the guy selling the lathe, and vetoed it.) Charlie Lear, Melbourne, Australia clearx~xxsteammachine.com Hutt Valley Model Engineer Soc. http://steammachine.com/hvmes Eastern Bays Little Blue Penguin Foundation: same site /penguins ------- Date: Sun, 9 Mar 2003 21:48:03 EST From: catboat15x~xxaol.com Subject: Re: Re: Tapping PVC metalmugerx~xxyahoo.com writes: > Anyone know if you can tap pvc piping for threads? Thanks in advance. Manufacturers of PVC pipe say you should not tap or thread schedule 40, but schedule 80 has much heavier wall and can be threaded. I have both threaded and tapped PVC but take it slow and the chip is long and stringy. Flood with soapy water too it is easy to overheat the plastic. If you examine factory molded threads on PVC fittings you will see a rounded crest and root. Most plastics are notch sensitive (I.E. Potato chip bags, can't tear them, but cut a just a little and they tear right across.) I have threaded and tapped PVC pipe, but not in any critical areas. Tap one piece and die cut another and screw them together moderately tight and they will soon seem like one piece since the plastic seems to "flow" under pressure and self weld. ------- Date: Tue, 1 Apr 2003 16:04:41 -0800 (PST) From: Pete Brown Subject: Problem milling plastic - any ideas? I am milling some plastic rounds on my mill using very thin end mills. I'm basically making a die of a spoked HO-scale locomotive wheel. The problem I've had so far, is that the plastic (UHMW and ABS, both seem to have the same thing going on) both have "peels" at the edges of the part. It's hard for me to explain, but basically when I'm done milling the slot that would eventually be a spoke, there is very thin plastic hanging out the end of the slot and also protruding from the top of the slot. The thin plastic is still attached to the piece, and is difficult to remove without screwing up the part. Is this normal for plastic milling, or am I doing something wrong? Keep in mind I'm very new to this, so make no assumptions :-) I'm following the example set in the Dec? 1998 issue of Mainline Modeler where the modeler did exactly what I am trying to do. No mention was made of the "peelings". I'm open to any suggestions! :-) Thanks. Pete p.s. I forgot to add that the end mills I am using are resharpened wire-size carbide end mills from drillbit city. They appear to be sharp. ------- Date: Tue, 01 Apr 2003 20:39:36 -0500 From: Daniel Munoz Subject: Re: Problem milling plastic - any ideas? Some climb milling (a second pass in the opposite direction) should get rid of most the "peels". I also had this problem with UHMW. I don't know if a cutting fluid could help. I think is it basically because that kind of plastic is very soft and "elastic". Couldn't you use a harder plastic, like Acrylic (plexiglass)? I had some good result with it, using VARSOL (paint thinner) as a cutting fluid. Look here: http://www.nutsnbits.com/acrylic_tank_wheels.htm > I'm following the example set in the Dec? 1998 issue of Mainline I don't know this article, but are you sure the modeler was using UHMW or ABS? Cheers. Daniel http://www.nutsnbits.com ------- Date: Tue, 1 Apr 2003 20:43:48 EST From: wlindiii53x~xxaol.com Subject: Re: Problem milling plastic - any ideas? I machine a lot of UHMW for work not hobby...and what you describe is very typical milling operations. In turning operations, UHMW will make virtually an endless shaving if allowed too...but that toughness is also what makes it a great material for many applications. I am not as familiar with ABS so can't help there. I might suggest trying Delrin rod stock if possible which should greatly reduce the burring on the edges you describe. Basically you aren't doing anything wrong in my opinion, just the property of the material being used. Hope this helps Bill ------- Date: Tue, 1 Apr 2003 18:05:16 -0800 (PST) From: Pete Brown Subject: Re: Problem milling plastic - any ideas? The article specifically mentioned ABS, but it looked more white (might have just been because of the camera flash) Someone else mentioned acrylic off-list. I think it might be worth trying for this type of work. Any problems with splintering or cracking? Do you mill the acrylic like aluminum or ...? Thanks. Pete ------- Date: Tue, 01 Apr 2003 21:13:04 -0500 From: Daniel Munoz Subject: Re: Problem milling plastic - any ideas? >Any problems with splintering or cracking? Do you mill the acrylic >like aluminum or ...? Yes, just as brass or aluminium, with slow rotating speed. Not too fast or the heat from friction will melt it. But it is brittle, so you must be careful with very thin pieces. If it start melting, stop the machining immediately or you'll have difficulties to removed the melted acrylic from the end mill. Guess how I know that :-) My advice is you have choice is to use brass instead for tiny parts... it's so nice and easy to machine. Daniel http://www.nutsnbits.com ------- Date: Tue, 1 Apr 2003 20:58:00 -0800 From: "Marcus & Eva" Subject: Re: Problem milling plastic - any ideas? Hi Pete: Get yourself some Delrin barstock. UHMW is very difficult to machine cleanly. ABS is a bit better, but will burr easily and tends to melt. It's also not very strong. Delrin is beautiful to machine and finishes like glass with sharp cutters. Its only drawback is that it's almost impossible to glue. Cheers Marcus ------- Date: Tue, 1 Apr 2003 23:16:44 EST From: catboat15x~xxaol.com Subject: Re: Problem milling plastic - any ideas? You may be melting some of the plastic with the heat from cutting. Can you flood the work space with water without ruining your mill? Or a jet of compressed air is sometimes used for cooling. John in the high desert of California 12 inch Atlas Mini Mill Rusty file ------- Date: Tue, 1 Apr 2003 23:25:47 -0600 From: "mwhirailer" Subject: Re: Problem milling plastic - any ideas? Has anyone mentioned slowing down the cutter speed? Terry Wellman St. Charles, IL ------- Date: Wed, 2 Apr 2003 09:22:35 +0200 From: Roger Jonsson LINE AUDIO Subject: Re: Problem milling plastic - any ideas? You need a very sharp tool to reduce (what would direct translate from Swedish as) cutting-beard :). I use a precision 3mm (1/8") tungsten/carbide (I think) 2 flute endmill, the same I use for aluminium. Climb milling helps reducing "cutting-beard" as well and gives a perfect finish. If you can use another plastic, try Poly-acetal plastic (POM), it's a marvelous plastic, like cutting butter yet the plastic is very strong, tough and you can get excellent finish and precision AND no "cutting-beard" what so ever. My cuts are usually 5mm (1/5") deep and the feed is up to 4mm/s (1/6" / s = 9" / minute)! Maybe a little slower when climb milling. I also cut Poly-ethene (PE), it's a cheap very soft plastic. It cuts easilly, but I can't get rid of the cutting beard. Now you have read "cutting beard" four times. Sorry five, now. Hope you had fun! ;-) All the best, Roger Jönsson. Line Audio Design tel +46 44 22 54 96 Åhusvägen 74 fax +46 44 22 54 20 291 76 Rinkaby email: rogerx~xxlineaudio.se Sweden http://www.lineaudio.se ------- Date: Wed, 2 Apr 2003 07:31:58 -0800 (PST) From: Pete Brown Subject: Re: Problem milling plastic - any ideas? Thanks. I tried some Delrin and had similar results with the burrs. In fact, last night I quickly tried Delrin, ABS and UHMW and all had similar burring. I'll have to do a more involved test, however. Someone mentioned it might be melting. On inspection, it didn't look melted, however. I'll slow it way down and see what I get for results. Pete ------- Date: Wed, 2 Apr 2003 09:24:36 -0800 From: "Marcus & Eva" Subject: Re: Problem milling plastic - any ideas? Hi Pete: If you can't get good results in Delrin, then your cutters are not behaving properly. If they are reground, you've probably not got enough side relief on the flutes. Buy yourself one brand new Niagara cutter in the size you need and try that. You should get a silky smooth surface with no burs at all. Cheers Marcus ------- Date: Wed, 2 Apr 2003 22:55:56 +0100 From: "Andrew S Knox" Subject: RE: Digest Number 1093 Try http://www.polymerprocessing.com/polymers/POM.html Short but sweet, DuPonts Delrin, as already mentioned. I quite like polycarbonate, even with quite slow and small feeds it cuts clean, but if too small a cut of fast a spindle speed you can get the swarf to weld if this is the bearding your on about (interesting term...) Regards Andrew ------- Date: Wed, 2 Apr 2003 18:12:02 -0800 (PST) From: Pete Brown Subject: Re: Re: Problem milling plastic - any ideas? I did a quick unscientific test today. THe UHMW burrs (beards? ) at even slow spindle speed and feed. The ABS does as well, but not as much. The delrin, which burred at high speed, seemed pretty clean at low speed. I'll play around with it some more later this week. Pete My Personal Site: http://www.IrritatedVowel.com ------- Date: Thu, 03 Apr 2003 05:26:25 -0000 From: "jlupher2" Subject: Feed rates on foam Hello everyone. I just got a Taig mill, the 2017LE, day before yesterday, and I've have to say that it is just plain fun. I have only slept about six hours since I got it! We are using it to make prototype parts for product development. The parts are usually made via SLA and then tooled for injection molding. So, I am trying to figure out the optimal use of the Taig for prototyping. My guess is we will end up cutting foam, or modeling board for development work, and then make a working prototype out of the material the production product would use (ABS or PC or PP). Our goal is to cut parts faster and cheaper than our typical (outsourced) SLA turn. BTW, I am a veritable newbie when it comes to CNC, but I am learning a lot lately! Questions: When cutting foam, what feed rates can I reliably use? The foam is nothing to cut, but the steppers can only go so fast? When cutting harder stuff, it seems likes a cutting strategy is the key to getting a part done quickly. How many different end mills are people using when cutting blocks of plastic or modeling board? I have been using Deskproto, but does it pay to get a more advanced toolpath generator package? Is simulation of the toolpath essential? Nice to have? Thanks in advance for any help. John ------- Date: Thu, 3 Apr 2003 08:38:56 -0500 From: "Carol & Jerry Jankura" Subject: RE: Feed rates on foam Hi, John: Your questions are not specific to Taig products, so here's what I'm doing with a Sherline CNC mill. Everything should be applicable to you. When setting up your CNC system, you'll have to set up parameters such as acceleration, maximum velocity, etc. The goal here is to make your machine rapid moves as fast as possible without losing steps. How do you tell if you're losing steps - well, the motors may very well stall out. Or, if you have double ended motors with a knob on the back end, just touch the knob a little and you'll feel the stutter in an otherwise smooth rotation. Since every mill is different, expecially after you adjust gibs, etc. you'll have to experiment with this on your own. I've worked with my machine's parameters until the motor was performing just below its stalling point. Then, I backed off of the maximum velocity by about 10-20%. Also, you'll have to test each axis separately, as the parameters will probably be different for each. I'd suggest that you join yet another list on Yahoo - CAD_CAM_EDM_DRO. It's sole purpose in life is to help folks set up and use CNC in a 'home' environment. The questions that you've posed here fit directly into that charter, whether you're a 'home machinist' or not. Jerry ------- Date: Mon, 16 Jun 2003 17:51:22 -0000 From: "Charles Hixon" Subject: Re: turning wood with sherline lathe [THIS THREAD CHANGED SUDDENLY INTO A PLASTICS DISCUSSION] You might avoid composites like glass-fiber reinforced polyester (fiberglass) because the glass fiber is silica and turns into sandpaper-type grit as you fracture the fiber during machining. Paper-, Cotton-, and Carbon-reinforced composites may not be as bad. Probably the easiest way to determine which fiber you have is to look at their fractures under a microscope. Plastic manufacturers generally have a machinability rating for their grades of plastic. Some of them list their rating on the internet. The problem is often identifying what plastic you have and you want to get this up front. If you buy analytical Fourier- Transform Infrared Anaylysis service to identify it, you will more often than not narrow it down to a few possibilities. Those possibilities can be eliminated or supported by individual thermal or chemical tests, depending on what you've narrowed it down to. Then it's a matter of sifting through various manufacturer's listings to try to determine if they offer it and what their trade name is for it. When you have that determination, you have a listing of properties, including machinability. Also avoid glass-fiber reinforced melimine. You might know this as the green or brown PC circuit board material. Excellent material, but you're machining sand when you hit the glass. Throw that sand into your aluminum ways and you've got a loosy-goosy mill. Charles ------- Date: Mon, 16 Jun 2003 21:03:17 -0300 From: "Neil Albert" Subject: RE: Re: machining plastic with sherline Charles: Does this mean my plans to machine some PCB patterns on my Sherline definitely out? Do you know if there are blank PCB's made with a substrate other than glass-fiber reinforced melamine that would be safe to use on the Sherline? Neil ------- Date: Tue, 17 Jun 2003 02:27:04 -0000 From: "Charles Hixon" Subject: Re: machining plastic with sherline Neil: You can't beat melamine for abrasion resistance, strength, dielectric properties and flame resistance. There's no substitute IMO. Glass fiber is used as much as a reinforcement material as it is a filler. It's the glass fiber that's the problem, not the melamine resin. The nearest alternatives might include whatever varieties of polymers are used for distributor caps for instance, but at least some of these are fiber-reinforced - I don't know the varieties - nor the types of fiber used as filler. Maybe they're all melamine with glass too. Before melamine, there was rubber, hard rubber and Bakelite. That's what my 80 year old fire truck is equipped with. I don't know the PCB business: you gotta do what you gotta do, but I'm keeping my mill out of the sandbox. Too bad you couldn't use some type of small CNC overhead gantry device. All I can think of is the obvious: shield your slides and collect and contain the residue ASAP, maybe with a vacuum cleaner turned on and attached to the spindle housing, disassemble, clean and re-grease your slides often. Charles ------ Date: Mon, 16 Jun 2003 19:39:26 -0700 From: "Dave Hylands" Subject: RE: Re: machining plastic with sherline Hi Neil, I haven't used these myself, but I've heard that you can get phenolic substrate on PCBs, which is much more cutter friendly than fiberglass. There is a Yahoo group with lots of good links to suppliers and such: http://groups.yahoo.com/group/Homebrew_PCBs/ (click on the Links area) Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ ------- Date: Tue, 17 Jun 2003 02:47:21 -0000 From: "Charles Hixon" Subject: Re: machining plastic with sherline Yea, Bakelite is a phenolic, lots of different kinds of phenolics around. Not as good as melamine, but a step up from hard rubber. I like to turn replacment knobs out of phenolic blanks. Charles ------- Date: Tue, 17 Jun 2003 00:28:31 -0400 From: "Statman Designs, LLC" Subject: Re: Re: machining plastic with sherline Neil: I have no experience machining PCBs on anything. I do know that the Sherline machines can take an amazing amount of abuse. I have abused my long-bed lathe for 5 1/2 years machining only grade-5 titanium. After machining I then sand and polish the pieces while spinning on the lathe with emery cloth and jeweler's rouge. I am sure that everyone here will tell you not to grind or polish over the bed ways. It is just a matter of the level of convenience that you desire. I view my Sherline's (2 lathes and 3 mills) as completely and totally disposable. If it wears out or breaks, every single part is available individually directly from Sherline and can be delivered overnight. I have replaced nearly every part on my long lathe and one of the milling machines, and many of them more than once. I can tear the entire machine apart and re-assemble it in about 1 1/2 hours (or less). If you need to cut PCBs, then I say just do it and deal with the wear items as they develop slop. Of course, I make money with my machines, so it is definitely NOT a hobby for me. Daniel J. Statman, Statman Designs www.statmandesigns.com dan.statmanx~xxrennlist.com ------- Date: Mon, 16 Jun 2003 23:54:32 -0500 From: Ron Roske Subject: Re: Re: machining plastic with sherline Neil: Lots of phenolic boards out there to chose from. Single sided, dbbl sided, various thickness. Should work well for what you are planning on doing. The thicker stuff won't flex as much as the thinner and probably would be more applicable for your purposes. Radio Shack carries some and other electronic supplies will have them, too. Best of luck on your proposed projects and let us know how they come out. RonR ------- Date: Tue, 17 Jun 2003 10:42:30 +0200 From: Roger Jonsson LINE AUDIO Subject: Re: machining plastic with sherline There are special endmills for glass-fibre PCBs. I use them frequently. Milling PCBs is 100% problem free and the result is rater good, using these endmills. Cuts very easily. I don't know the original source, I buy them from Solectro www.solectro.se , here in Sweden. They also carry good tungsten-carbide PCB drills as well sa PCBs and machinery. All the best /Roger Jönsson ------- Date: Tue, 17 Jun 2003 10:46:12 -0700 From: Alan Marconett KM6VV Subject: Re: Re: machining plastic with sherline Hi Neil: There is a home-brew PCB list on yahoo you might check out: Homebrew_PCBsx~xxyahoogroups.com The light brown phenolic boards are "soft", and can easily be milled. The swarf won't harm the ways. Also, the swarf can be contained. Put a temporary cover over the ways. A 1/2" hose plumbed up to a vacuum cleaner will keep it picked up. It usually just piles up on the PCB, anyway. About the only real problem is the short life of cutters! Use carbide if possible. A few boards won't hurt much. John Kleinbauer's site gives some info also: http://www.kleinbauer.com/ DeskCNC and DeskPCB programs (IMService) can handle Gerber files for milling. Eagle has a PCB layout program (some free) that is great! http://www.cadsoftusa.com/ HTH Alan KM6VV SherlineCNC ------- Date: Tue, 24 Jun 2003 22:00:15 -0000 From: "variousgroups" Subject: Delrin (acetal) in Colors Anyone? Does anyone know of a source for Delrin (acetal) bar stock in colors? Black and white I've got plenty of, I'd like some red, yellow, blue, green, the basic colors. I need a cross section at least 1.25 x 1.5 inches. Mike ------- Date: Tue, 24 Jun 2003 17:55:12 -0500 From: "mwhirailer" Subject: Re: Delrin (acetal) in Colors Anyone? Mike: I would try TAP Plastics. They're on the web and supply a lot of plastic including Delrin. That's where I get mine from. They have several distribution points throughout the country. Terry Wellman St. Charles, IL ------- Date: Sat, 28 Jun 2003 14:07:27 -0000 From: "variousgroups" Subject: Colored Acetal (Delrin) - Source For Only one company I've contacted thus far offers colored acetal (Delrin ®: Modern Plastics in Bridgeport, Connecticut. I sent an email inquiry to each of several firms for bar stock with a minimum cross-section of 1.5 square inches. Here's the reply from Modern: "Thank you for your inquiry - "As a standard item, colored Delrin acetal products are not available. However, we do stock a number of rod materials in acetal copolymer (a very similar product to Delrin)in sizes from 1.500" to 3.000". Perhaps you could use the rod instead. The rod is typically used for "medical" type applications, but we have found that customers who want to have colored Delrin without having to pay for large minimum runs, this was an alternative. "The rod closest to your request would be colored medical grade acetal 2.500 diameter, Blue, black, green, and yellow are currently available x~xx 54.40 /ft. lengths are 4 feet long. Please let me if you would like to order." David A. Altieri - V.P. Sales and Marketing Modern Plastics, Inc. 678 Howard Avenue, Bridgeport, Connecticut 06605-0574 203 333-3128 - Extension 207 800 243-9696 - National Toll-Free Line 203 333-4625 - Fax Number www.modernplastics.com Best, Mike ------- Date: Wed, 06 Aug 2003 00:37:20 -0000 From: "jchrisj7734" Subject: Re: cutting carbon fiber plate > Anything with carbon fiber in it is going to be highly abrasive. > Where I work we use diamond saws and carbide to machine carbonfiber > composites. If your plate is a laminate, be extra careful about > creating disbonds at the interfaces. Keep it slow and the cuts light > and you should be OK. Also, we cut everything wet to keep things > cool and to keep the dust under control. HTH, Mac We cut carbon fiber reinforced polymer composite panels with a wet cutting diamond saw at work. One thing to keep in mind is that carbon fiber is electrically conductive so you really want to control the dust. We had a series of computer power supply failures in our processing lab where carbon fiber dust was a strong suspect. Using an extender box to keep the monitors, mice, and keyboards in the lab and the computers in a more protected environment settled the problem down. You don't appear to need long pieces of fiber to cause those problems, the dust is enough. You probably don't want to breathe the stuff, either. ------- Date: Wed, 06 Aug 2003 00:50:07 -0000 From: "Gary Severson" Subject: Re: cutting carbon fiber plate I do a little hobby laminating and I use a carbide dremel bit that is labeled as a tile cutting bit for triming the flash off if that is your intended use. Gary Severson ------- NOTE TO FILE: Various subjects during July-October 2003 in the Metal_Shapers group contained info on how we might make a replacement gear for the Phenolic bull gear used in an AMMCO shaper; those are reported in the AMMCO Shaper text file and may be useful to others faced with making special gears or otherwise working with Phenolic materials (resin-cloth laminates available under many names). ------- Date: Sun, 19 Oct 2003 21:31:51 -0000 From: "Art Volz" Subject: Military Standards for Phenolic Resin Fabric Laminates I have researched current US Army files today and have found the Military Standards that apply to Phenolic Resin Fabric Lamininates. The Military Standard that provides general specifications is MIL-I- 24768, dtd 25 Feb 92, and entitled: Military Specifications-- Insulation, Plastics, Laminated, Thermosetting, General Specifications For": http://assist.daps.dla.mil/docimages/0000/95/07/24768.PD1 . At paragraph 1.21.a "Cotton Fabric Base, Phenolic-Resin Binder" it lists four such plastics for possible consideration as cut gears: --FBE--Electrical Grade --FBG--General Purpose --FBI--Machining Applications --FBM--Mechanical Grade In Table XXIII "Cross-Reference Guide For Laminates" are provided the Industrial Designations for the military ones: --L = FBI --LE = FBE --CE = FBG --C = FBM http://mcmaster.com carries in stock phenolic laminates in these four industrial designations. For gears, the finer weave L and LE grades are probably the ones to use. In this regard, I have today "won" an auction for a 14-inch x 24-inch x 1-inch thick slab of LE grade with which I and Mike F. will conduct gear cutting experiments--hopefully successfully--commencing with the attempt to cut a 10-inch OD bull gear wheel for a Lewis with a DP of 8. Specific Military Standard specifications for these four grades of phenolic laminates are at: FBE: MIL-I-24768/13 -- -- http://assist.daps.dla.mil/docimages/0000/21/86/106225.PD9 FBG: MIL-I-24768/14 -- -- http://assist.daps.dla.mil/docimages/0000/21/87/106226.PD0 FBI: MIL-I-24768/15 -- -- http://assist.daps.dla.mil/docimages/0000/21/87/106227.PD1 FBM: MIL-I-24768/16 -- -- http://assist.daps.dla.mil/docimages/0000/21/87/106228.PD2 I have only conducted a rapid scan of these Mil Specs but didn't immediately see any specific information on machining. I do have general machining data for phenolics in my "Machining Data Handbook" from which I will extract some starting cutting data--tool type, feed, speed, and DOC--and post here sometime later this week, as time permits...and Yahoo obliges. Art (Houston North) I have posted spec sheets for Garolite CE and LE Grades (from McMaster catalog) in a "File" titled "Phenolic Laminates" at http://www.groups.yahoo.com/group/Metal_Shapers_Pix . ------- Date: Mon, 17 Nov 2003 07:49:44 -0000 From: "mileagemayvary" Subject: Re: 2 flute mill sucks more? In sherlinex~xxyahoogroups.com, "neilalbert2001" wrote: > I am machining a plastic part whose bottom is a fairly thin horizontal > plastic surface, and I am concerned that this section will lift as it > is being machined Can be quite a problem. The thing I have found in this situation, depending on the plastic type, is to keep the heat down to avoid warping deformation. A very sharp tool, fast feed, and turning the speed down. The hold down tape should be a help but could be counterproductive by insulating the heatsinking of the table. ------- Date: Tue, 13 Jan 2004 22:45:58 -0000 From: "Lee Owens" Subject: Looking for **small** amounts of acrylic and teflon rod The local supply shops don't have rod in the scrap pile. I need acrylic for making model car parts like tranmissions, rims, oil filters, etc. Buying 12feet at a time would get me 5 lifetime supplies. Can anyone spare a foot or so of various diameters of acrylic, lexan, or teflon? I'd be happy to pay for it. I just don't need 12 feet of each. Looking for 1/2inch up to about 3 inches. Thanks, Lee ------- Date: Tue, 13 Jan 2004 23:45:52 -0000 From: "Jim Knighton" Subject: Re: Looking for **small** amounts of acrylic and teflon rod Lee, I don't have a complete solution for you, but you might look in outfits that sell pen making supplies. Last weekend I was in the local Woodcraft store and picked up some phenolic resin blanks - not for making pens, but as blank stock for other projects. The stuff might be ugly, but you're probably going to paint it anyway. The stuff I got was about 6" long, 3/4" diameter and also some blanks roughly 1.5" diameter x maybe 2 or 3" long. Also, McMaster-Carr sells some industrial plastics by the foot. Several months ago I got a 2' length of delrin from them. I hope this helps. Jim Knighton ------- Date: Tue, 13 Jan 2004 18:58:57 -0800 (PST) From: Scott Meyer Subject: Re: Looking for **small** amounts of acrylic and teflon rod Try McMaster-Carr at www.mcmaster.com. They have all kinds of "industrial" materials inlcuding teflon, acrylic, and I imagine Lexan and the others you mention. You also might try www.onlinemetals.com. They have lots of different metals, but also teflon, delrin, some acrylic, etc. They do specialize is small orders, and cater to the hobbiest quantities. I have used Online Metals, and like them alot. I have not used McMaster in years, but never had a problem with them. Scott ------- Date: Wed, 14 Jan 2004 18:49:52 +1200 From: "Richard T. Perry" Subject: Delrin, etc... I don't use the stuff much myself, but when I have, I've gotten it from Small Parts in FL (try www.smallparts.com) We just got a bunch at work to (re)make some rollers for the side doors in the UH-1 helicopters we service here. Smallparts isn't the cheapest place in the world, pound for pound, but when you only NEED a pound..that's who I go to. A quick browse through their catalog shows about 6 different plastic types in various diameters up to a couple of inches in 3" to 36" lengths. Also, I got a really nice "grab bag" of UHMW plastic blocks from Woodcraft a few months back (I was making a jig.) 3 pounds for $10, p/n 143291. Really nice stuff - feels like teflon, machines like aluminum (but use carbide bits, not HSS, like the instructions say... I proved that one the hard way). Good luck! Regards, Richard T. Perry ------- Date: Wed, 14 Jan 2004 09:48:43 -0500 From: "Mike DeMetz" Subject: Re: Looking for **small** amounts of acrylic and teflon rod MSC(www.mscdirect.com) sells plastic rod in 1 ft lengths. ------- Date: Wed, 14 Jan 2004 15:25:54 -0000 From: "Kevin Williams" Subject: Re: Looking for **small** amounts of acrylic and teflon rod This may not help for "small" quantities, but one of the best suplliers of plastics I have found is Ridout Plastics - http://www.ecomplastics.com/index.html . They have just about every type of plastic in a variety of shapes (rod, tubes, plates etc) and size, plus the proper adhesives and even tools for cutting plexiglass. For acrylic they have both cast and extruded shapes, cast acrylic machines much better than extruded acrylic. Their website has lots of good info about plastics, including machining characteristics. They will ship small amounts of most items, but the catch is is they have a minimum $100 order. So, for example, they will sell you 1 foot of 1" black Delrin for $4.39 plus shipping, but you will have to put together an order of $100 to get anything. I have placed orders with them in which the $100 minimum was composed of a half dozen different sized items. Kevin ------- Date: Wed, 14 Jan 2004 16:12:55 -0000 From: "Bryan Hassing" Subject: Re: Looking for **small** amounts of acrylic and teflon rod Hi Lee: I build 1:24 scale model big rigs. I use my Sherline long bed lathe, occasionally equipped with a vertical milling column and rotary table, to make parts like those you mentioned. While I buy my Evergreen Scale Models or Plastruct sheet products from local hobby shops, I get all my plastic rod from McMaster-Carr (http://www.mcmaster.com). I use their beige ABS rod which cuts like butter using standard Sherline 1/4" HSS lathe tools. I have made various size truck tires on the lathe and really like the glass- smooth finish I get from the ABS rod. A side benefit of using ABS is that it is easily sanded and painted. McMaster-Carr sells 0.250", 0.375", 0.500", 0.625", and 0.750" diameter ABS rod in 5-foot lengths only, but the larger diameter ABS rod is sold in 1-foot increments. The 5-foot length materials show up in a nice, sturdy four-inch mailing tube with end caps, which is what I use to store the spare material. While I also don't need five-foot lengths of these materials, at least I can experiment all I want and never fear running out of stock. I don't McMaster has a minimum order requirement. I did a quick check between McMaster and MSC Direct and found that the ABS rod is about 30% cheaper than acrylic in diameters up to about 1". The cast acrylic rod is about 30% cheaper than ABS once you get up to the large diameters like the 3" you mentioned. MSC will sell the small diameter ABS rod in 1-foot increments too and is slightly less expensive than McMaster. Hope this helps. Bryan ------- Date: Thu, 05 Feb 2004 18:14:30 -0000 From: "Brian Chapman" Subject: Flycutter question I'm working with various sizes of ABS plastic sheet. At the moment, .080"; as with all plastic sheet I've used so far, the ABS varies a couple of mils in thickness from one spot to another. I used the flycutter for the first time just now; it left ridges from one row to another. Might this mean my attempts at squaring the Sherline 2000 mill needs work (wish I had not bought the 8-axis model); what can I do to correct the problem? Sure appreciate any help with this I can get. Thanks much, Brian Chapman Cedar Rapids, Iowa ------- Date: Thu, 05 Feb 2004 18:50:06 -0000 From: "mc_n_g" Subject: Re: Flycutter question If you can not cut the whole width at once with a flycutter, it is very hard to not get small ridges. Without an extremely balanced flycutter and heavy mill you will never get a truly flat surface with flycutters. There are a lot of forces acting on the mill when you use a flycutter and the head must be very stable. Read the study in flycutter design a month or so ago in the Homeshop Machinist. There is a lot of good information. You may also be having problems with a wrong cutting rake angle. Not having a long smooth radius on the cutter.... That is a whole different ball of wax. mc_n_g ------- Date: Sat, 7 Feb 2004 14:15:29 -0800 (PST) From: Jim Izzolo Subject: Re: Tapping plexiglass witstock7 wrote: >>>I need to tap some 6-32 holes in 1/4 inch plexiglass and can't find any info on what to use as lubricant. Any suggestions appreciated. Nelson>>> I may be wrong but I think water with a little bit of oil works. You also need a bit that is made for drilling through plexiglass. It has a different angle than metal or wood bits. Sorry I cant help you more, but I am sure others will know more than I do about this and I will learn from them as well as you. Jim ------- Date: Sat, 7 Feb 2004 15:33:54 -0800 From: "Dave Goodfellow" Subject: RE: Tapping plexiglass I tapped smaller holes (4-40) in the plexiglass cylinder block of my I Spy engine, with no lubricant at all. The plexiglass does want to grip the tap, so I needed to back out often. Also, once I was at depth I needed to run the tap back and forth several times to open it up enough to get the screw started. The tapped hole had some resistance to accepting the screw, but for my purposes that was a good thing; the screw would not back out under vibration. I've been told (don't know from experience) that any of the oil-based tapping fluids will damage the plexiglass. If I really needed to use some lubricant, I'd try Crisco or butter -- or maybe some vegetable oil. Experiement with some scrap plexiglass and see what they do before using it on your workpiece. Dave Goodfellow Lancaster, CA http://www.davegoodfellow.com/ ------- Date: Sat, 7 Feb 2004 23:32:58 -0000 From: "Nelson Wittstock" Subject: Re: Tapping plexiglass I did a dry tap on a scrap piece and had no problems but just wanted to make sure that there isn't a better way before I do the "real" pieces. These will be drilled almost all the way through but not completely and then tapped with a bottoming tap. Thanks for the input. Nelson ------- Date: Sun, 8 Feb 2004 01:20:30 +0100 From: Pavel Koøenský Subject: RE: Tapping plexiglass I am using normal HSS drill bits and normal taps. Everything works OK, if you put a bit of water on them. Or simply, spit on them. The main problem with plexiglass is temperature. If the temperature is low enough and the glass does not melt, everything is OK. Best regards PavelK ------- Date: Sun, 08 Feb 2004 00:46:59 -0000 From: "Radish" Subject: Re: Tapping plexiglass If you get hold of an OLDER drilling and tapping chart, you will find mentioned on this chart that PARRAFIN can be used as a tapping or drilling agent. If you check out what is mixed in the newer formulas for tapping and drilling, you will find that parraffin is part of the make-up of these newer agents. So why not by bypass this newer stuff and use one of the original agents, by the way, this stuff works wonderfully well and it sure is a lot cheaper than these newer mixes. This stuff is recomended to be used on copper and brass so it sure is slippery, I use it on everything, steel, brass, aluminium and even acrylic/plexi-glass, you can even see the thread being formed when you use it on clear acrylic/plexiglass. No damage what so-ever when you use it on any of the above. You can buy this liquid parrafin at any chemist/drugstore, it is still used as a laxative, so if your job is giving you the sh*ts, take a swig of your tapping agent and you too can have the sh*ts. radish ------- Date: Mon, 16 Feb 2004 13:15:16 -0000 From: "chimpygoo" Subject: Re: Plastic recommendation and speed control In taigtoolsx~xxyahoogroups.com, "ejbardet" wrote: > I am just getting started in building some scale shop tools (1:24 > scale) for a 1900 era facility and I have a few questions. > 1- Which is the best plastic to use? I know styrene is quite > popular, but I was wondering about machinability. ed, there really are no best plastics for all app's, but i can tell you this: machinability of styrene is pretty bad - unless you have a specific reason to use it, such as cost or color, there are many easier plastics for a novice to machine. --acetal/delrin-- by far the best all around machining plastic, but can be very expensive unless you can get it surplus. ---pvc/cpvc-- good machining , moderate cost, can get surplus at good prices. ---hdpe/marineboard/starboard-- recently there's been a ton of this stuff on ebay- machines incredibly easy ,fairly strong, and can sell unbelievably cheaper than just about anything else. ----nylon and polypropylene-- also available fairly cheap, but more challenging to machine...tends to grab large drills(esp p/pro) > 2- What I have read indicate that slow speeds and heavy cuts are the > secret to working with plastics. Are the slowest speeds available on > the mill and lathe appropriate or do I need a speed reducer? If I do > where can I get one? might want to brush up on some basic machining practice,i.e. feeds and speeds..to start with..the appropriate speed rpm has everything to do with the diameter of the workpiece(lathe), or dia. of the cutter(mill) to arrive at the working SFM(surface feet/minute)which is appropriate for that material. sfm=(cuttingspeed x 4)/ dia of part or cutter. but.. in practice, esp without coolant, plastics don't behave like metals- metals wick the heat into the part, platics tend to "insulate" the tool and capture the heat= you'll want to use heavier feeds to keep tools from melting the plastics. so... in pvc , for example, i might turn a 1" diameter at 900rpm and a 1/4" piece at 3000 rpms. ...but if i were to run a 1/4" drill into pvc at 3k , say 1" deep w/out coolant i'd soon have a gooey mess melted all over the drill...probably run that .25 drill at about 900rpm. on the lathe the tool won't generate nearly as much heat because the area of contact/insulation is much smaller =much faster rpm's. won't melt everything as fast. makes no sense , right ? welcome to plastics. get some scraps and practice-make notes of what works and what doesn't. use carbide tools if you can-plastic can be very abrasive and can dull high speed tools faster than steel. i've been machining pastics in production for 15 years....the only way to figure it out is trial and error. > 3- Any good books on working with plastic? > 4- Is there an on line source of correct FPM numbers for the various > plastics? the various mfg's ( G.E. , Dupont, 3M,etc..) have charts and thingies with reccomendations and such, but i've always found them less than useful---might be a good place to start though. good luck Ed ------- Date: Mon, 16 Feb 2004 09:57:29 -1000 (HST) From: Tom Benedict Subject: Re: Re: Plastic Recommenation > Do these scale shop tools have to be in plastic? Personally, I would > consider using brass - it is very easy to machine. Alan Smith Lemme second that. Brass is an absolute blast to machine. I've been told aluminum bronze is equally fun to cut, though I haven't had the opportunity to try this. A while back I was griping about copper, and was told that there are nice copper alloys for machining. I accidentally ran across one while making some parts for work. The thing started life as a big honkin' grounding bar for a power grid. It's about 1/4" thick, 4" wide, and several feet long. The stuff cuts like brass! So there are three materials to try. In the wood department, ebony cuts a lot like brass. It's a strange wood to cut but the machining characteristics are almost a carbon copy of brass. Cast iron is also pretty nice to cut, though the "chips" are basically metal sand. If you put a strong magnet inside a plastic baggie and stick it near where you're cutting, most of the iron chips will cling to the magnet instead of flying around your shop. When you're done, turn the baggie inside out and pull it off the magnet. Voila. Clean magnet and all your chips are in the bag. Honestly from the standpoint of realism as well as from the standpoint of ease of machining, I'd give brass or gray cast iron a try. They're pretty neat and you'd have a fully functional miniature when you're done. Tom ------- Date: Wed, 26 May 2004 02:52:27 -0000 From: "asrpas" Subject: How to part-off many piecs out of long plastic extrusion? Hi, Could someone suggest best way to part-off 1/2" pieces out of long ABS plastic solid rectangular bar, I need to make 200 pcs. Idea is to buy rectangular section and cut the required section profile on the whole length and cut it off into 1/2" pcs, imagine like we make T- Nuts but this section profile is more complex than t-nut.(section is about 1"x2") My question is; Can I use Miter Saw to cut those pieces? I don't have mitersaw so can't try thought better ask before buying. Another point is I need to have good finish after parting off and can't afford to machine each face after parting. Is there any sort of burning or melting on plastic using saw. If I use taig mill to cut off using endmill it'll take forever. I'm open for any suggestion or ideas. Thanks in advance. Regards, Rick ------- Date: Wed, 26 May 2004 04:22:48 -0000 From: "Ed Chesnut" Subject: Re: How to part-off many piecs out of long plastic extrusion? I'm a manufacturer of injection molded ABS control stick grips for small aircraft. Upon reading your question I went to the garage and cut a blemished grip in half on my table saw. The resulting finish was pretty darn good with clean sharp edges and no burr - and no melting. The blade on my saw is 10", about 40 teeth, Alternate Bevel teeth, carbide tipped. The blade could be in better shape since I use it for cut-to-length operations on 1/8" wall Aluminum tubing (6061 T6) AND for cross cut and rip operations on recycled lumber. With a chop saw or miter saw with good bearings x~xx the hinge point and a good sharp blade designed for smooth cutting - I think you'll be happy as a clam. Ed ------- Date: Fri, 6 Aug 2004 12:41:07 -1000 (HST) From: benedictx~xxhawaii.rr.com Subject: Profililng acrylic [taigtools group] I haven't done much in the way of milling with acrylic. Engraving, yes. Turning, yes. Hoggin'out and profiling, no. What's a good combination for profiling acrylic? I can likely rough with a 1/4" or 1/8" mill, but will need to finish with something smaller, say in the 1/32" size. (Metric or Imperial is fine by me. I'm not picky.) The work itself is going to be pretty small, say 1/2" wide by maybe 1" long, probably smaller. Can I use standard end mills or is the geometry too far off that it won't give good results? Surface finish is unfortunately pretty important, though a mirror finish isn't required. But minimal tooling marks would be good. Far as coolant goes, I've got mist coolant, an air jet, or me with a squirt bottle available. For drilling ABS I've had good luck with the air jet, but I'm up for ideas here. Thanks, Tom ------- Date: Fri, 6 Aug 2004 20:43:10 -0700 From: "Felice Luftschein and Nicholas Carter" Subject: Re: Profililng acrylic Travers has single flute solid carbide routers (Micro 100 brand) in their latest sale catalog, down to 1/16" dia. The sales blurb says they have a polished flute and are ideal for plastics. About $15-$20 each.... I hear soapy water works well, I imagine mist would too. The key as I understand acrylic is to avoid heat, and have a sharp tool. Check out our homepage www.cartertools.com/nfhome.html ------- Date: Sun, 08 Aug 2004 00:39:05 -0000 From: "buddyborders" Subject: Re: Profililng acrylic The only problem with soapy water is the cleanup. Kerosene (paraffin) works well for a cutting lube and can also be mixed with sulfer based cutting oils if available. Negative rake tooling, like that used for brass, works well I find. Especially when drilling holes to avoid/minimize breakout on the back side of the part. HTH. Buddy Borders Philadelphia, PA ------- SAFETY WARNING: CUTTING CARBON FIBER products produces extremely hazardous dust and particles. Research the health hazards and employ all industry and OSHA mandated and recommended safety equipment and protective rules and safety measures adequate for your particular situation and work before ever starting! Seriously consider safer alternative materials for your projects, or having a competent professional company do all this dangerous work for you. ------- Date: Wed, 15 Dec 2004 17:50:21 -0700 From: "Doug Powell" <4machiningx~xxcomcast.net> Subject: Re: Cutting Carbon Fiber? [taigtools] Original Message ----- From: dkp_design >> I would like to know if anyone has experience cutting carbon fiber sheet in their mill. If so, what bits and feed speeds did you use? I cut my first piece tonight, it drilled excellent, but frayed when I cut it out. I was using a 2 flute carbide .125" cutter at max speed, 2IPM feed. Any help or suggestions? Carbon Fiber is expensive material to be having a bunch of test pieces. << I cut carbon fiber nearly every day producing parts for RC race cars. I use 3/32" solid carbide up cut circuit board cutting bits and circuit board drills as well. The CF is very abrasive and dulls the cutting bits quickly. I cut at high spindle speed and 10 inches per min. The optimum spindle speed would be about 23k. At that speed the feed could be considerably faster. Contact me off list if you have more questions Doug Powell ------- Date: Wed, 15 Dec 2004 20:22:27 -0000 From: "Dave" Subject: Re: Cutting Carbon Fiber? I was an f-18 mechanic, that whole plane is carbon graphite. You need to use a diamond coated burr. It works more like a rotary file than an end mill. Lots of rpm (20k for a .25 tool) and use plain water to cool and keep the dust down. Drilling use a 60deg pointed bit, similar to an engraving bit with one or 2 flutes. Graphite dust is very bad for your lungs. Remember a graphite splinter works its way into your skin not out like a metal or wood one. ------- Date: Thu, 16 Dec 2004 09:06:34 -0500 From: Ken Jenkins Subject: Re: Cutting Carbon Fiber > So, I would have more luck with a Dremel? I have some drills that > are almost a flat point, they do seem to drill nicely. I have some > rotary file type bits for my dremel. That was my original plan, to > make a template out of alum and use the Dremel to cut it out. That > was until I got my Taig :D You might try using a laminate trimmer to get your high RPMs. A Dremel won't hold up very well. I mounted a Dewalt laminate trimmer in place of my mill spindle using a mount made out of a Taig riser block. It works great for engraving, woods, plastics, etc. You can see it here: http://kj.cloudcitydigital.com/pages/taig_mill_d660mount.html Ken J. ------- Date: Wed, 15 Dec 2004 12:47:58 -0800 From: "Larry Richter" Subject: Re: Re: Cutting Carbon Fiber? > Graphite dust is very bad for your lungs. Remember a graphite splinter > works its way into your skin not out like a metal or wood one. Oh, man. Meaning the fiber splits out of the matrix with a barbed surface on it? That's the nastiest thing I've heard about it. ------- Date: Wed, 14 Dec 2005 21:51:39 -0500 From: Rich Crook Subject: Re: Plastic recommendation [taigtools] At 08:18 PM 12/14/2005, Larry wrote: >I purchased a Taig mill a few weeks ago and also bought many assorted >types of material to practice with and have been really learning a lot >(making swarf mostly). I have successfully machined Delrin, UHMW, >Teflon, ABS, PVC, Acrylic, Polycarbonate but was wondering what would be >the the recommendation of an easily machined plastic that is also >glueable to itself without special equipment. My current candidates are >ABS, PVC, Acrylic, and Polycarbonate but perhaps there is something >better. The material cost is not too important and the color does not >matter. Would the recommendation change if I also wanted the chosen >plastic to be glueable to aluminum or steel? I worked for 10 yrs in an industrial modelmaking & prototyping shop, and we used primarily acrylic plastic (aka Plexiglas or Lucite) to fabricate all kinds of things. Very versatile stuff - it machines easily, can be readily heat-formed and can be solvent welded with liquid model-building cement (methylene chloride.) We would usually hold it down on the machine with thin double-sided tape (*not* the foam type!) & pry it loose with a thin putty knife when done. It takes some practice to learn how much tape is enough without overdoing it. Xylene (aka xylol, a paint solvent) works nicely to help release stubborn tape without damaging the acrylic. (It *will* attack polycarbonate, tho!) Methylene chloride, "two-face" tape and Bondo were absolutely essential supplies in the model shop. This same solvent will also work on styrene, polycarbonate (aka Lexan or "bulletproof" glass), butyrate and ABS, and should be available at any hobby store that sells plastic model kits. I have a 2 oz botle of "Ambroid Pro-Weld" that cost $3.19 at the local hobby shop; 2 oz will last you quite a while. (Just keep it tightly closed - like many solvents, it evaporates quickly.) Acrylic plastic can be either cast or extruded ("extruded" sheet is actually rolled.) Cast stock is more expensive, but machines better, and has an optically clear surface (it's cast between sheets of plate glass.) Extruded is more prone to "gumming up" if it gets too hot while cutting - it partially melts & forms a white crusty surface. One caveat for cast sheet - the surfaces are optically flat, but it usually won't be quite uniform in thickness - I've seen variations of .040 -.050" from one end/corner to the other on a 4x8' sheet. Extruded sheet, however, is very consistent thickness due to being run thru rolled to size. Gluing plastic to aluminum or steel could be tricky. A cyanoacrylate glue (SuperGlue, CrazyGlue, etc) is probably best if you have a tight fit, but the joints may break if subjected to shock loads (sharp impact) or excessive heat. Note: "SuperGlue solvent" is just 50% mix of acetone & water - i.e. nail polish remover. (The acetone is what does the work.) Rich ------- Date: Thu, 15 Dec 2005 10:01:18 -1000 (HST) From: benedict-listx~xxhawaii.rr.com Subject: Re: Plastic recommendation Excellent material, Rich! I'm saving that post. As far as gluing plastics to metal, I wound up doing a fair number of test on this a while ago while trying to build an assembly jig for a fiber optic bundle. Specifically, I was looking for stuff that DOESN'T stick. Teflon was the clear winner in the "can't stick me down!" category, followed closely by Delrin. I managed to get everything else to stick. I tested two epoxies. One is Stycast, which I use at work for vacuum feedthroughs. The stuff is like tar, and needs to be heated to 60C in order to even mix in the catalyst, but it sets up hard, reproduces really fine detail, and sticks like crazy to just about anything that's had good surface prep (cleaning with alcohol worked well.) Another was Tra-Bond F113 Bipax. It's an optical epoxy, VERY runny. It comes in pre-measured packets, so to mix it you remove a clip and squish the stuff back and forth in the packet. It's got good capillary action, which is why I wound up selecting it for the fiber bundle. I did a test plate with a bunch of different materials stuck on it, including a chunk of aluminum that had a thin film of vacuum grease on it. Teflon didn't stick, Delrin kinda stuck, but nylon, PVC, aluminum, brass, and steel all permanently bonded to the test plate (which was aluminum). Even the greased aluminum stuck, which confused me greatly. As a result of all this I built the fixture out of Teflon and it worked like a charm. The epoxy bonded the fibers to their alignment fixtures, and the whole shebang popped out of the jig just fine. For plastic machining at home I like PVC because the stuff is so dirt cheap. Given the choice I'd use Delrin, but not if the parts need to be glued to other parts. After reading Rich's post here, I'm tempted to do more in acrylic. Tom ------- Date: Thu, 15 Dec 2005 19:03:29 -0600 From: Codesuidae Subject: Re: Plastic recommendation Alex Holden wrote: >How _do_ they get Teflon to stick to frying pans? Funny that you ask, my kid asked me that the other day, and I had to look up this link: http://www.discovery.com/area/skinnyon/skinnyon970606/skinny1.html Basicly they put on three coats, the first coat is a sticky version of the polymer, the second coat is the non-sticky version, but it still has a molecular affinity to the sticky version, then a third layer that is the non-sticky version with some bits of ceramic or other tough stuff to give the non-sticky some strength. More recently some clever guys have figured out how to bake a mixture of all the stuff so that it self- organizes and makes a better coating faster. :) Anyway, the info about the epoxies and whatnot was interesting and useful. I'm curious about the fixtures made out of teflon though, can you just buy chunks of it and machine it? Do you have to use a lube when you cut it? :D Dave K ------- Date: Thu, 15 Dec 2005 16:46:12 -1000 (HST) From: benedict-listx~xxhawaii.rr.com Subject: Re: Plastic recommendation NEAT! I'm sending that URL around here at work. I've had a slug of it sitting in my desk for ages. That's the one I used for the fixture (the biggest feature of which was 10mm long). But I checked in the shop, and we've got a fair amount of Teflon. I think it's the same as buying any other plastic. The stuff machines like a mix between nylon and Delrin. It's got a lot less tendency to make stringy hair than Teflon, but isn't nearly as dimensionally stable as Delrin. This was the first time I've really made parts with it. Neat stuff! Tom ------- Date: Thu, 15 Dec 2005 22:39:35 -0500 From: Rich Crook Subject: Re: Plastic recommendation >I'm curious about the fixtures made out of teflon though, can >you just buy chunks of it and machine it? Do you have to use >a lub when you cut it? :D I want to know how you hold on to it so it doesn't move! Kinda like grabbing a wet bar of soap... I knew a guy once who was flycutting a block of delrin - it slipped out of the vice jaws & the flycutter flipped it clear across the shop (a good 30-40')! Got *everybody's* attention right quick! Kind of in the same league as belt sander racing or chuck key tossing... (If you have to ask, don't! ) Rich ------- Date: Fri, 16 Dec 2005 09:41:28 -1000 (HST) From: benedict-listx~xxhawaii.rr.com Subject: Re: Plastic recommendation > I want to know how you hold on to it so it doesn't move! Kinda like > grabbing a wet bar of soap... It was. I took super light cuts and checked the setup over and over again. Even so, I did have some slippage and had to re-clamp and re-indicate a couple of the parts. But everything was done in a good ol' Anglock vise with parallels. Tom ------- Date: Fri, 16 Dec 2005 15:56:14 -0500 From: Stan Stocker Subject: Re: Plastic recommendation If you degrease the moving jaw of the vise you can stick 400 grit or so paper to it with double sided carpet tape. The fixed jaw can get the same treatment or be left as a reference surface as usual. Once done the jaw cleans up easily with a bit of solvent. In some other cases, two sheets of fairly fine abrasive glued together on the substrate side gives a slip resistance surface that isn't inclined to damage mill tables when used with a bit of discretion. This can be useful if you need to clamp a sheet down flat. Cheers, Stan ------- Date: Fri, 16 Dec 2005 21:58:29 -0000 From: "Lynn Livingston" Subject: Re: Plastic recommendation > (good luck trying to glue it!) Nah, it won't glue with anything permanently. But, welding it is easy and is permanent. Lynn ------- Date: Mon, 23 Jan 2006 15:09:45 -0800 From: Nicholas Carter and Felice Luftschein Subject: Re: Fly Cutter [taigtools] > I need to level the surface of an acrylic panel. > this part has to be flat accurate at a precision of 0.0004" > I want to program it to mill away all the material of the top. > Questions: > a. Can it be done with a regular cutter? (the panel is small) Yes, basically use a pocketing routine to mill across, step over, mill across, step over, etc. until done... > b. Or do I need a fly cutter to do it? is a fly cutter more accurate > then a regular cutter? Yes and no...with a small cutter you may get steps between passes. With a fly cutter you won't get as many steps, but the flycutter will magnify any misalignment of the x and y axis in respect to the spindle more than a small cutter would. A flycutter can use a roundnose tool and you can hone it to be razor sharp so that you will get a very smooth cut. Why not try both and see what happens? See our homepage at www.cartertools.com/nfhome.html ------- Date: Mon, 23 Jan 2006 23:11:46 -0000 From: "Lynn Livingston" Subject: Re: Fly Cutter Asi: What are you getting yourself into?????? ;-) I assume by prior posts that you are relatively new at machining? If so, then you are like a lot of us. I can't imagine getting myself into something that would require that kind of accuracy, and if I did, what tooling and setups it would take to do the job. How are you going to know if you have it machined to this spec? What kind of measuring device do you have that could measure and or compare a flat surface that would tell you for sure that it was within .0004 from one point to another across the whole surface? Are you grinding mirror mounts for NASA, or laser reflectors for IDOD?? ;-) Just curious... Lynn ------- Date: Mon, 23 Jan 2006 23:17:00 +0000 From: Tony Jeffree Subject: Re: Fly Cutter Machining anything flat to an accuracy of 4 tenths on a Taig mill is going to need very careful setting up - firstly to make sure that the column & spindle are accurately perpendicular to the plane of the table, secondly, to make sure that the plane of the table surface is accurately parallel to the plane of *movement* of the table (i.e., the plane described by the X and Y axes), and thirdly, that the material you are machining is clamped in such a way that the clamping action itself doesn't distort the material by an amount comparable to the accuracy you require. The latter in particular is going to be an interesting problem to solve with a material as flexible as acrylic. If you get the conditions described above right, the choice of cutter will be somewhat secondary in importance I believe. Regards, Tony ------- Date: Mon, 23 Jan 2006 15:36:17 -0800 From: Nicholas Carter and Felice Luftschein Subject: Re: Re: Fly Cutter leon_heller wrote: > A fly cutter doesn't produce a flat surface, it's very > slightly 'dished'. Leon Well a perfectly aligned machine would give a flat cut, but given that no machine is perfect, you will get a dish that corresponds to the amount of misalignment of the spindle to the table. And let me add to everyone else's comments, .0004" is getting into a situation where you would really use a surface grinder rather than a mill. Then again you could mill it then use a lapping plate to lap it flat. But then you need a lapping plate...and probably 3M lapping film, as compound would just get embedded into the acrylic. See our homepage at www.cartertools.com/nfhome.html ------- Date: Mon, 23 Jan 2006 16:01:08 -0800 (PST) From: juan gelt Subject: Re: Fly Cutter i suggest buying a 35 $ grade b granite slab certified to that and using it to both lap and support your sheet while cutting. if your eye sees cutter marks, you aren't there at 0.0004 yet. at that level of flat you should see a rainbow like on a cd. i'll bet a nickel you CAN NOT achieve that surface quality by any cutter on a taig. it's a beautiful little beast, but everything has a limit. cheap precision reference stuff, including the amazing 300$ 3 FOOT by 4 FOOT 4 inch thick granite slabs...i can't believe the prices... shipping prices are sort of...angioparalytic [usual disclaimer- no financial interest, opinions my own, etc.] ------- Date: Tue, 24 Jan 2006 14:01:06 -0000 From: "combelis" Subject: Re: Fly Cutter To all of you interested in what I want to do, here goes: I need to make panels from clear acrylic 0.23" thick. After I cut the panel for holes, shape etc', I need to engrave. How is the engraving being done? First, I apply 3 layers of white paint on the clear acrylic. Then I apply 2 layers of black paint. Now comes the tricky part :) I need to engrave only the black, so the final result will be a black panel with white letters. This panel will be backlit from behind. Problem is that sometimes the cutter "eats" the white too, leaving a clear letter, which is a bad result for me. The 3 or 4 layers of white give about 0.002" thickness. (I don't want to use "whole white acrylic", simply because the white text doesn't look as good as paint). I assumed that the acrylic panel was very accurate and flat, and the paint is causing the diference in the surface level. But my indicator showed that the clear acrylic has height differences along the surface at about 0.0015". How do I know that? I checked the panel at 8-10 different points. If I can make the basic clear acrylic accurate and flat, the painting will not harm the accuracy level of the surface. Then I'm ready to go. I want to say that I already succeded doing my first panel :) How? Well, it took me a while, but it's my hobby so I enjoy spending the time. I mapped the g-code, in such way that I know the g-code block for each letter. Then I find the highest point of the panel using the indicator. (Simply move it to 8-9 deferent points). I bring the cutter to the highest point, finds the surface level and start engraving at 0.001". After it finishes, I check which letter is O.K and which one need to go deeper. The ones that are o.K, are removed from the g-code. Then I go deeper more at 0.0003" etc. Until all the letters are engraved properly. I know this method takes time, and this kind of job isn't built for this mill,but if there is one major thing I learned from this group is: "if it works, it works :) " I believe that if I can level the clear acrylic, it will save me the time of the process I described above. Asi ------- Date: Tue, 24 Jan 2006 14:10:40 +0000 From: Tony Jeffree Subject: Re: Re: Fly Cutter Sounds to me that you are introducing a further problem here - that of ensuring that the layers of white paint are of a consistent thickness (not a trivial thing to do IMHO). The more conventional approach to this kind of job would be to screen print rather than machine away the top layer - have you thought about that as an alternative? Regards, Tony ------- Date: Wed, 25 Jan 2006 19:11:26 +0000 From: Tony Jeffree Subject: Re: Re: Fly Cutter 25/01/2006, you wrote: > I thought these were to be backlighted. I don't think silkscreened > characters would work... Neil Savage You don't silkscreen the *characters*, you silkscreen the background colour *around* them (in this case, black I assume). So if the material you are screening onto is translucent & you use an opaque ink, the characters can indeed be backlit. Regards, Tony ------- Date: Wed, 25 Jan 2006 10:50:41 -0000 From: "infidel21st" Subject: Re: Fly Cutter Asi: Have you checked the forums over at Viperpit.org? There is a lot of experience over there making cockpit panels using the CNC taig. I believe the material of choice is delrin. I haven't seen anything to date indicating there was this kind of issue. Chris Crowley ------- Date: Wed, 25 Jan 2006 13:24:42 -0000 From: "combelis" Subject: Re: Fly Cutter Chris: How did you know I'm doing those kind of panels? :) For those who are interested, I'm a simulator fan and I'm building a replica of an F-16 Cockpit. I already spoke with Mike from ViperPit. He is using "white" Acrylic so he doesn't have the problem like me. The thing is, IMHO, that using "white" acrylic doesn't give the same results. The text comes out a little dim. Asi ------- Date: Wed, 25 Jan 2006 11:29:41 -1000 (HST) From: benedict-listx~xxhawaii.rr.com Subject: Re: Re: Fly Cutter >> first, I apply 3 layers of white paint on the clear acrylic. then I >> apply 2 layers of black paint. Now comes the tricky part :) >> I need to engrave only the black, so the final result will be a black >> panel with white letters. this panel will be backlight from behind. >> problem is that sometimes the cutter "eats" the white too , leaving a >> clear letter , which is a bad result for me. The 3 or 4 layers of >> white give about 0.002" thickness. >> (I don't want to use "whole white acrylic", simply because the white >> text doesn't look good as paint). On Wed, 25 Jan 2006, Lam wrote: > Hi Asi this might be considered cheating but i would just mask up the > black near the clear letters and airbrush in the white for a final > touch up : ) Following up on what Lam said, take a look at this: http://www.cuttingedgecnc.com/vinyl.htm In this, the author details all of their attempts at making a rotary knife holder for a CNC Sherline for cutting vinyl. They go through five iterations on the blade holder, and pay attention to enough details that the thing will cut the vinyl but not the backing. As far as doing multiple parts that need to be in registration to each other, the author has info on doing that as well. If you could CNC your masks, apply them to your panel, airbrush around them, and then peel the mask off, you may be in good shape. Plus, you'd have a CNC vinyl cutter in your shop to boot. Can't beat doing a project and getting a tool out of it. Tom ------- Date: Tue, 04 Apr 2006 06:15:01 -0000 From: "Chuck Fellows" Subject: UHMW Bearings [LittleEngines] Anybody ever tried making crankshaft bearings for a small steam or compressed air engine out of UHMW? Chuck ------- Date: Tue, 4 Apr 2006 09:07:30 -0700 From: "corey renner" Subject: Re: UHMW Bearings I've used UHMW to make bearings before (also used it to make a replacement rib for a convertible top on a '66 beetle) it worked well. I've never used it in an engine, but I would imagine that it would work well for that too. cheers, c ------- Date: Tue, 4 Apr 2006 10:26:41 -0700 From: "rwremington" Subject: RE: UHMW Bearings Materials such as Delrin and glass reinforced Teflon (Rulon) are usually considered better bearing materials than UHMW polyethylene. There are some graphite/molydbenum disulfide filled plastics that would work as well. Dick R. ------- Date: Tue, 4 Apr 2006 13:43:30 -0700 From: "corey renner" Subject: Re: UHMW Bearings On 4/4/06, James E. Andreasen wrote: > I know I'm dumb, but what is UHMW? James Not dumb at all. It stands for Ultra-High Molecular-Weight Polyethylene. Pronounced as "Ump-ee" on the shop floor. It is a food-grade self- lubricating plastic. It looks similar to white Nylon, but is dimensionally stable and doesn't absorb water (hence food-grade). I used to design food- grade conveyors and we used the stuff a lot. I used to take a lot of cut-offs home for my shop. cheers, c ------- Date: Tue, 04 Apr 2006 20:54:11 -0000 From: "Chuck Fellows" Subject: Re: UHMW Bearings I have a fair amount of the stuff that I picked up on eBay. I know it's a little tricky to machine, since it's kind of springy and tough. But it seems like it would have enough flexibility to compensate for bearings that weren't in perfec alignment (not that anyone in this group would ever make an engine with bearings slightly misaligned :)) Chuck ------- Date: Tue, 4 Apr 2006 14:02:43 -0700 From: "corey renner" Subject: Re: Re: UHMW Bearings The key to machining it is very sharp tooling. It cuts well, but if the cutter rubs it just makes a mess. c ------- From: "benedict-listx~xxhawaii.rr.com" benedict-listx~xxhawaii.rr.com Date: Wed May 10, 2006 1:34pm(PDT) Subject: Re: How to lathe plastic? [taigtools] On 10 May 2006, phoneteamd wrote: > I am a complete newbie. I am trying to round a set of pinewood derby > wheels on the lathe. How do a cut the plastic? What RPM? My first > attempt has caused bumps like waves on the top of the wheel tread. > How do I make it cut smooth? Here's how I'd do it: Make sure the wheel is mounted super super solidly. What you're describing sounds like chatter. Since you're making an interrupted cut (each gap in the tread will let the tool stop cutting and start again on the next tread), rigidity is going to play a big role in this. Make sure your tools are hair-splitting sharp. This isn't a cure-all for the kind of chatter you describe, but it helps a ton. After grinding I dress my tools with a little diamond hone I picked up from the hardware store. Nothing special here, and any hone would work. At home I use a Norton stone for this step. You should be able to shave your fingernail with the tool by the time you're done. Also make sure there's a SMALL radius at the tool tip. I don't do this on the grinder since it's hard for me to control. After dressing the tool I pass the hone around the tip of the tool a couple of times. Depending on the radius I want I use more or fewer strokes with the stone. Three strokes is enough for me to see the difference between it and a razor- point tool with no radius. The radiused tool will cut silky smooth while the razor-point tool will cut grooves. Use a slow feed across the wheel. Going fast will make grooves rather than a smooth surface. Ideally your tool advance per revolution on a finish pass should be on the order of the radius on the nose of your tool or smaller. Listen to the cut. If it's squealing, something's up. Take a heavier cut (probably not possible if you're truing wheels), slow down the spindle, or feed faster. If the combination you need means you're cutting grooves instead of a smooth surface, then try adding more of a tool tip radius and try again. Something to consider is using some sort of lube or coolant. Plastic tends to do ok cut dry, but it can do weird things if it heats up enough to flow. Try dribbling a little water during the cut, just to see what it does. One lube trick I picked up here on this list was to use cetal alcohol. I started using this as a tapping fluid, and it works GREAT. I can't remember who wrote this particular tip, but Chapstick is primarily cetal alcohol. I keep a stick in my toolbox at work now. I haven't tried it on plastic, but it's worth trying if it stands a chance of giving you a better cut. All machining considerations aside, have you checked the rules and regs where you'll be competing? A while back when I was looking at cutting a pinewood derby body on the CNC mill (I know... I know... I'm SICK) I saw a lot of competition rules expressly forbid the use of machine tools on the wheels of the car. The ones that did allow it tended to limit it to things like you're doing, namely truing up the wheels but not modifying them in any other way. Some excluded even that (which makes no sense to me, since the alternative they suggested was to chuck the wheel up in a drill and basically do the same operation.) Just be sure of the rules before you compete. Hate to get a DQ over a technicality like this. Tom ------- From: "benedict-listx~xxhawaii.rr.com" benedict-listx~xxhawaii.rr.com Date: Wed May 10, 2006 6:22pm(PDT) Subject: Re: How to lathe plastic? On 10 May 2006, phoneteamd wrote: > Wow! This is a big help. I have a bunch of old wheels to experiement > with. You have given me a lot of ideas to get me started. > One thing I don't understand is what tool to use to cut with? When I > purchased my lathe it came with a six piece set of cutting tools. The > are "left,right,45 degree,round nose,boring bar, and cut off" Which of > these should I try? lso any ideas on angle to hit the wheels with? Typically turning cuts on a lathe start at the tailstock end and move toward the headstock. For what you're doing this is the way I'd do it. The tool you'd want for this kind of cut should look like this (pardon my ASCII art): |\ | \ | \ | \ | | | | | | |XXXXXXX| |XXXXXXX| Ok, ok, so that's not the best rendition of a lathe tool I've seen, but it's a try. I know the angle at the tip isn't that steep, but you get the idea. I'd hit the wheel with the tool just about in that orientation. The idea of the angles at the tip are to provide clearance so the tool doesn't rub. So long as only the tip of the tool is touching the wheel, you should be in good shape. Of course, as you might've guessed, theres more to it than that. The tools that come with the Taig lathe are a pretty good generic set of tools, but the angles really aren't ideal for any one material. They're a good compromise for several. In the long run it helps to grind your own. The best bet for grinding tools is to get some tool blanks, a grinder, and some seat time. Sherline's got a really nice guide for grinding lathe tools: http://www.sherline.com/grinding.htm The one difference between what's said there and what I do at home is I don't break the tip on the grinder. I do it by hand with a stone. My fine motor skill is so-so, and I tend to put huge chamfers on my tools if I do them on the grinder. I also notice the recommendation that tools not be dressed with an oil stone after grinding. I can't say I share the same opinion, but that's all it is: an opinion. If the idea of grinding your own tools makes your stomach sink, don't sweat it too much. I've wasted plenty tool blanks trying to get a particular shape on a tool. It's a matter of doing it until your hands know what to do. And lathe tool blanks are cheap, all things considered. I do curse under my breath when I screw up a lathe tool. But I curse out loud when I screw up an end mill, especially if it hasn't seen more than a few minutes of service. > Thanks so much for the help. You betcha. Best of luck with those wheels. Tom ------- Carbon fibre [taigtools] Posted by: "Chris Ghent" cghentx~xxtpg.com.au Date: Tue Jul 4, 2006 12:10 pm (PDT) Anyone know if it is possible to machine carbon fibre, and if so what is the nearest equivalent to the way it behaves? Plastic? Wood? What sort of cutters would you use? Apologies for lack of direct Taig relevance, but this is the only machining group I belong to. best wishes Chris ------- Re: Carbon fibre Posted by: "Jeffrey Wittman" eyecreatex~xxhotmail.com Date: Tue Jul 4, 2006 12:35 pm (PDT) As of late, I have been doing a fair amount of carbon machining, and the feeds and speeds are similar to plastics. The only difference being the cutter. You need to have a diamond coated cutter, and they are a little pricey (40-50 bucks for a 1/8th inch 4 flute), but they really are the only bits that you will have any life with (believe me I have tried many others). They are usually refered to as an "amorphous diamond coating", but there are several different types. Check out Niagara Cutter online, as they will give a good idea of what you are looking for. (They make cutters specifically for carbon:) BTW, I dont know if it is relevant to your application, but if you need to do any machining of fiberglass, they also require the same kind of bits as they are more abrasive then carbon composites are. Jeff ------- Re: Carbon fibre Posted by: "Doug Stout" kingshouse41225x~xxgmail.com Date: Tue Jul 4, 2006 9:16 pm (PDT) I have machined both carbon fiber and fiberglass, and with the proper endmill they do machine quite nicely. Aside from the diamond coated EM, I will add that flood coolant helps dramatically, and is simple to set up, even on the taig. Fabricate, or have fabricated a pan which fits on the table. Run a drain from the back side of each end down into a bucket on the floor. A submersible pump, run to some flex hose and a nozzle mounted on the mill and you are in business. The coolant not only helps extend the life of the tool, it eliminates the dust. ------- Re: Plastic types and suppliers? -- [taigtools] Posted by: "Richard" phrhx~xxworldnet.att.net Date: Thu Jul 6, 2006 3:40 pm (PDT) A nice to machine material is PVC such as schedule 40 pipe. I cut pieces fom 6" diameter pipeand heat it in a scrapped electric grill and it becomes flat and can be made really flat when a cement block is used to cool it on a concrete floor. An example of what can be done with it is shown in the links section in this group under Richard's shop. Look at the cheap dividing head. It glues up very nicely with PVC glue. Smaller diameter schedule 40 PVC is a great cheap material for lathe practice for threading practice if you are so equipped. Richard ------- Re: Plastic types and suppliers? -- Posted by: "Richard" phrhx~xxworldnet.att.net Date: Fri Jul 7, 2006 5:11 am (PDT) > Do you have any problems with outgassing of the pvc when you flatten > it? What temperature do you set your electric grill to when you do > this? I like the idea. I will have to give it a try. I have never measured the grill temp but set the dial (Sunbeam grill from walmart) between low and medium, Not very hot. The PVC pipe section unrolls when it gets warm enough and can be sandwiched between concrete blocks or anything flat and heavy to cool and it will stay flat. I have not noticed any gassing or nasty odors! ------- Re: 4 Flute vs 2 Flute in plastic [taigtools] Posted by: "Nicholas Carter and Felice Luftschein" felicex~xxcasco.net Date: Wed Oct 18, 2006 9:55 am (PDT) Ackley, Ray (R.J.) wrote: > Hi all, > I'm a bit of a machining beginner here and I found some peculiar > behavior with a 4 flute bit I picked up. > When I run the 2 flute bit I got through Nick/Taig though the plastic > I'm cutting it cuts perfectly clean and quietly at any spindle speed. > But the bit isn't deep enough for my needs, so I picked up a 4 flute > thinking "Hey, if 2 flutes are good, 4 must be better, right?". Wrong. > The 4 flute makes a terribly loud sound when cutting and also wind up > "flaying" the plastic in such a manner as it creates extremely fine > strands that somehow melt it back into place? The end result is a "cut" > plastic edge (by the sides of the bit) that has some kind of a weird > plastic fuzzy "hair" on it. It's very odd. > My google searches on 2 and 4 flute differences have yielded NOTHING > that could possibly explain this. Any ideas? > Thanks, Ray Ackley I'm going through some plastic machining hell myself. You want less flutes rather than more, and you want a slow spindle speed. The key is to not melt the plastic, or even soften it by overheating. You want to make the biggest chips possible. You can take a endmill and relieve the shank above the flutes a bit on the bench grinder (or surface grinder for a better grind) so you can use a short flute on a deep part. I was talking to Forrest at Taig and he said they used to put a stream of CO2 (or a Vortex type cold gun) on the part to keep it cold while cutting, I just bought a 1 flute plastic routing bit (specially made for soft plastic, by Onsrud) because I need to mill some UHMW and even a 2 flute endmill was melting the part a bit...$20 or so and carbide so I assume I'll destroy it accidentally... See our homepage at www.cartertools.com/nfhome.html ------- Re: 4 Flute vs 2 Flute in plastic Posted by: "Ackley, Ray (R.J.)" rackleyx~xxford.com Date: Fri Oct 20, 2006 8:16 am (PDT) Well I put in the new 2-flute and it works great... simple as that! ------- Machining Delrin [taigtools] Posted by: "davidjaypark" davidj93x~xxhotmail.com Date: Wed Feb 21, 2007 5:45 pm ((PST)) Hi all: Just curious to note if any of you have experience machining black delrin plastic? If so was interested in getting your thoughts in respect to speeds and feeds. Will be using a 1/4 flat end mill all the way down to a 1/32 ball nose end mill. Use a Mfg. calculator but the largest material multiplier is 2 for aluminum. It doesn't have any numbers for plastic, so I thought I would ask you guys. IF you could let me know your experiences with milling Delrin using the Taig and what your feeds & rpms were it would be great! Thanks so much for the help and will talk to you soon! Parkman ------- Re: Machining Delrin Posted by: "Roy" rx~xxshred2.net Date: Wed Feb 21, 2007 6:33 pm ((PST)) You can pretty much rapid through black Delrin in my experience. You'll want to go fairly fast to avoid melting it. I don't have a speed/feed off the top of my head, but some places suggest 400 sfm for HSS. Here's a link: http://www.cncplastics.com/PDFs/Machining%20Acetal%20Delrin.pdf ------- Re: Machining Delrin Posted by: "Landrum Haddix" lhaddixx~xxiglou.com Date: Wed Feb 21, 2007 6:55 pm ((PST)) Parkman, I used something like 10K rpm and 5ipm with a 1/8" cutter and .060 doc. It's made to be machined, it doesn't seem to care. It didn't try to melt even at that high of an rpm and low feed. Acrylic is totally different, but Delrin is ideal for cutting. A 1/32 ball end mill is going to break if you feed very fast and it's so small you can't go too high on RPM so it's a matter of what feed it will tolerate. If you are going to play with feeds on that be sure you have two or more mills on hand. I found a 1/16 end mill snaps somewhere between 10-15 ipm on acrylic. (I had to go for 15 and was sorry.) BTW if you ever need to cut something that melts easily like Acrylic, Harvey tool http://www.harveytool.com/ makes funky single flute cutters for plastic, but you don't need these for Delrin. It's fun and makes my enclosure look like one of those paperwieght snow scenes. Just for giggles here is a pocket in Delrin: http://lhaddix.net/machine/dustcover.html Oh, yeah you can use double-sided tape for fixturing as well. Landrum Haddix http://web.qx.net/lhaddix ------- Re: Machining Delrin Posted by: "Jeffrey Wittman" eyecreatex~xxhotmail.com Date: Thu Feb 22, 2007 6:01 pm ((PST)) At some point you may run across some reinforced acetal (Delrin is a trade name btw). Typically it comes with a glass reinforcement (fiber, powder, of micro spheres), and will quickly dull your bits. I have run into this because I often buy surplus (usually unlabelled). In this case try a diamond coated bit, which I have used on fiberglass, and carbon composite sheet with great success. Jeff ------- Machining UHMW on a shaper? [Metal_Shapers] Posted by: "Bill" manincocamox~xxyahoo.com Date: Sat Mar 17, 2007 12:09 pm ((PDT)) Hi All: Has anyone tried cutting UHMW on a shaper? [Ultra High Molecular Weight Polyethylene] Any tips or ideas on cutter angle grinding? Thanks Bill ------- Re: Machining UHMW on a shaper? Posted by: "Geoff Kingma" gkingmax~xxinterlog.com Date: Sat Mar 17, 2007 4:32 pm ((PDT)) I have used it on the shaper many times and it cuts very well. On the trailing edge though, the cut piece will still adheres so it looks terrible. A quick shave using a sharp knife cleans it up. I would say that the finish rivals that of aluminum. Geoff ------- Re: Machining UHMW on a shaper? Posted by: "Bill Williams" BWMSBLDRx~xxPeoplePC.com Date: Sat Mar 17, 2007 6:17 pm ((PDT)) > For those who aren't familiar with UHMW, my observations: it's a great bearing, hammer or slide material. Almost like a resiliant form of bearing bronze or aluminum in use. Very slippery material. I use it to shape sheet metal parts. Bill < You have had the experience that I have had; UHMW bumping hammers are a great starting point for forming aluminum and it turns nicely. Unlike nylon that tends to roll the chip over the tool tip and wind itself onto the cut surface, welding itself back on! Bill in Boulder "Engineering as an Art Form!" ------- Re: Machining UHMW on a shaper? Posted by: "Ed Godwin" eng4turnsx~xxyahoo.com Date: Mon Mar 19, 2007 10:25 am ((PDT)) Ultra High Molecular Weight Polyethylene. High Density Polyethylene (HDPE) is used for water and natural gas piping systems. Good stuff in many ways but it's worth a little study of its mechanical properties if you're going to machine it and use it for something of a precision or load-bearing nature. First of all, it tends to "give" when cutting so that if you think you've shaved off 0.050", you've actually taken off less than that. Also, if you're going to stress it in use, it has both a short and a long-term strength. You must use the lower long-term strength for any stressed part. Also, like Teflon, it will tend to flow with time. I've cut it successfully on the mill and the lathe with standard HSS grinds for steel but I'm sure you could do better with a little experimentation. Steeper rakes and less edge support would work well with this material since it has little resistance. A razor edge should be beneficial so it will shear instead of tear. HDPE in the color black is somewhat abrasive to the cutting edge due to the carbon black used to color it, so keeping the tool sharp is an issue if you're cutting a lot in the sense of production quantities. Overheating is an issue so don't overspeed. And the trailing edge of the cut will benefit from a sharper tool bit. If you use a sacrificial piece on the trailing edge of the workpiece, you will get a nice sharp edge. Since it cuts so easily, you will be tempted to take huge gobs of it off with each stroke. Resist this temptation and you'll get a better quality. Also, since it's relatively soft, simply clamping it in the vise will distort it, again calling for lower cutting forces than you might be tempted to apply. As with all things soft, a gentle touch works best. Ed ------- Re: Help needed [atlas_craftsman] Posted by: "uhmgawa" uhmgawax~xxthird-harmonic.com Date: Thu Sep 13, 2007 6:32 pm ((PDT)) artrich999x~xxaol.com wrote: > Is there some company or someone that can supply small, hobbyist-sized quantities (and prices) of acrylic plastics, or other machinable plastic? Needed is clear acrylic rods in 1/2" dia. up to about 1" dia. in pieces 3" to 6" long. Cutoffs, or slightly damaged pieces will do fine. < I don't know where you might find the red lens material but you might want to have a look at www.usplastic.com. Their minimum quantity purchase is fairly low as I recall. You might also check out www.use-enco.com as they carry plastic raw stock in various shapes. uhmgawa ------- Re: Help needed Posted by: "Jon Elson" elsonx~xxpico-systems.com Date: Thu Sep 13, 2007 8:07 pm ((PDT)) One great place is US Plastics. You won't get cutoffs, but they have nearly any sort of plastic material in many shapes and sizes. I mostly buy Teflon stock from them, but they have a TON of stuff in their catalog. I know their price on Teflon beats any other source. I think their minimum order is pretty reasonable, but then Teflon is pretty expensive stuff in general. Jon ------- Re: Help needed (Plastics source) Posted by: "azbruno" azbrunox~xxyahoo.com Date: Thu Sep 13, 2007 10:42 pm ((PDT)) First, nobody's mentioned yet the difference between cast acrylic and extruded acrylic. You want cast acrylic for machining. Extruded does not machine well at all. TAP has lots of extruded. I think you can get cast in clear, but not colored. My source is Delvies (http://www.delviesplastics.com/). The cast acrylic rod is sold in 4' pieces and the minimum is only $35. I've done a lot of searching and their prices are about the best I've found. You night be able to get all you need for the minimum. If you find short scraps, make sure you know what it is. I once ordered some rods of cast acrylic and was mistakenly shipped extruded (not Delvies). I could tell by the way is reacted when I used a small saw to cut off a piece... far more brittle. Bruno ------- Re: Help needed ... small lot acrylics [sherline group -- same question] Posted by: "jthandbook" jthandbookx~xxverizon.netp Date: Thu Sep 13, 2007 3:23 pm ((PDT)) Hi Art... You might consider Small Parts, www.smallparts.com. Their online catalog is incomplete but email inquiries get a fast response, service is as good as it gets. And they sell down to 3 inch lengths in cast acrylic round. Best, James ------- Turning Acrylic [sherline] Posted by: "steve" steve12345x~xxtalk21.com Date: Tue Oct 16, 2007 8:38 am ((PDT)) Hi, has anyone machined 'Acrylic' on his lathe and is able to give me advice on what speeds/feeds to use and what shape the cutting tip should be. The plan also calls for cutting a thread in the acylic for attaching the lid. After machining is there any advice on polishing? I'm making a small fuel tank for a model aircraft engine and I'd like to make it to drawing if at all possible. Thanks in advance. Steve ------- Re: Turning Acrylic Posted by: "Tony Horstman" tonyx~xxoryx.net.au Date: Tue Oct 16, 2007 4:06 pm ((PDT)) Steve: Acrylic is fun to turn. Speed should be slow to medium, because the material will melt quite easily. Keep the workpiece wet - I use plain water with a drop of dishwashing detergent for acrylic - you will quickly get a feel for speed and depth of cut versus surface finish. Tools should have rounded nose (for finish), but with a sharp upper cutting edge. Acrylic takes threads beautifully, as long as you observe that sharp peaks will be inherently very weak and prone to chipping. Acrylic, however, for all it's good turning and fantastic finish, is prone to stress cracking brought on by exposure to solvents, alcohol and hydrocarbons. Damage may not immediately be apparent, but a day later you may find you wonderful part neatly shattered. I googled this page, which is useful: http://microadvances.com/chemicals1.htm For a fuel tank, why not try polyethylene, delrin or similar - even easier to turn. Tony H ------- Re: Turning Acrylic Posted by: "Tony Horstman" tonyx~xxoryx.net.au Date: Wed Oct 17, 2007 6:32 pm ((PDT)) Steve: You're going to be disappointed with acrylic in contact with this mixture. It will most certainly disintegrate after a short period (often overnight, which makes taking a second look at your newly machine masterpiece really sad). Tools must be sharp for plastics, otherwise the tool rubs too much and melts a blob rather than peeling off a nice string. I use acrylic to machine small molds for vacuum casting (good to see what's going on inside, and easy to get a mirror polish). I recently got most of the way through a fairly complex core and cavity and picked up a nearby marker pen to mark a face that needed some extra work the next day. Put the core and cavity together, went home satisfied with progress. Next day saw the core neatly cleaved into 3 pieces on the bench. The solvent in the ink had evaporated in the closed cavity and cracked the part. Leaving the cavity open would've saved it. Live and learn. Tony Horstman ------- The use of plastic as a gib [atlas_craftsman] Posted by: "Bobby May" widgitsx~xxsbcglobal.net Date: Thu Jan 17, 2008 4:22 pm ((PST)) DennisF MacIntyre wrote: > I read a post a year or two ago where someone said what type of plastic > it was and why it is better (longer wearing)than the original equipment. Although many types of plastic could be used for this purpose we have to ask ourselves who knows more about these machines. The Engineers and machinists who designed and built them or the guy's who use them everyday. Several machine manufacturers have used plastics as a liner wear surface for gibs. One that I can think of from the top of my head is Fadal. They used to make the gibs for the box ways on their CNC vertical mills out of aluminum and line the wear surface with Turcite. The aluminum worked well to support the weight and the thin plastic Turcite shim gave it a smooth surface to slide against the box ways making the ways actually last longer. Fadal recommends also the use of Vactra #2 waylube for their machines But several things were considered before doing this such as the weights and forces applied to the parts in question vs the yield stregnth vs the drag (Cv) and stiction (static friction). The plastic also acts as a sacrificial media in case chips (swarf) get between these 2 surfaces. It actually allows the chip to get imbedded into the plastic and this reduces the scraping effect by reduction of weight and surface area above the chips. Better way of putting it would be that the chips don't get smashed into the ways Turcite works very well for this type of application. Pretty blue color. Rulon would be a good choice for bushings for shaft applications as long as the speeds and loads arent too high as it is much softer than Turcite. Deep red color. Torlon makes nice bushings and wear surfaces also, a bit pricey. Gold in color. Teflon (PTFE) is too soft and it changes size with just a few degrees of temperature change. White in color. Nylon would work but it wasn't compounded for this application and it's a bit softer than the others as such would wear much quicker. White to Cream yellow color. Polyethylene and polypropylene are also way too soft, even the UHMW (Ultra High Molecular Weight). White to clear white color. Vespel would be an optimum choice to make a gib out of as it is quite stiff and offers the lowest drag coefficient (Cv) out of them all, but the formula for making it and the patent rights have not yet run out to other manufacturers. Dupont owns it, Damn if it's not expensive !!! I was buying a billet of Vespel every couple of months for making some real expensive parts. A 10" x 10" x 2" thick blank costs just over $9000. Yes, thats $9000 US dollars for 200 cu. in. of plastic. I call it a bit expensive, but it's good stuff. Too expensive for making gibs out of. Deep Brown in color. Hope this helps By the way, I uploaded a cool PDF file (Fasteners_Handout.pdf) in the atlas_craftsman files section on fasteners and threads, It has some very good info if you like designing new stuff to build on your machines. Later Bobby May ------- Re: The use of plastic as a gib Posted by: "Bobby May" widgitsx~xxsbcglobal.net Date: Fri Jan 18, 2008 4:33 am ((PST)) Bill brought up the idea of using Delrin. This would be a good cheap plastic for making a gib out of. But I would anneal this before fabrication. I know, how can you anneal plastic? For delrin pop it in momma's oven at 200 deg F for about 4 hours for a little piece- 6 hrs if it's larger. This drives the moisture from the plastic making it stiffer and more stable for holding physical sizes. Plastics have many names for the same product. Delrin is DuPonts name for Acetal. But it's also known as Polyacetal, acetal resin, polyformaldehyde. And other manufacturers call it Celcon and Kepital. But it's made with formaldehyde. This is the smell you get when cutting it quickly; small quantities from smelling this stuff won't hurt you too bad. Something interesting about plastic names. Lexan belongs to GE (General Electric Plastics division). Everyone else has to call it Polycarbonate. Lexan outgases whats called Bisphenol-A, bad stuff as it is known to cause cancer and birth defects. Good tough stuff in the thicker sizes especially if you want to stop bullets. Teflon belongs to Dupont. Everyone else calls it PTFE (Poly Tetra Flouro Ethylene). Note the first and last word in PTFE -- Poly and Ethylene. Yes, this is the stuff they make TupperWare bowls and Cool Whip lids out of. It is also the base compounds for making Teflon. The stuff in the bottom of momma's fry pan is actually a form of thermoset teflon that is sprayed on like powder coating and then baked. Acrylic (PMMA) belongs to Rohm and Haas. Its real name is Polymethyl Methacrylate, that's a mouthful. Others call it Plexiglass and Lucite, but there's tons of other names for it also. Something cool is the use of some compounds for other things like cyanoacrylate (Crazy Glue). I would say that my biggest point here is to choose your plastic materials wisely. And be careful cutting some raw materials you might get for nothing as scrap rems as it might be very bad for your health. "No Way Bobby, that's not bad stuff." I have heard this many times before. Take a few minutes and look up "Aluminum Poisoning" on the Internet. You will be VERY surprised at what you learn. Here's one: http://www.squidoo.com/aluminumpoisoning Later Bobby May ------- Re: The use of plastic as a gib Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Fri Jan 18, 2008 7:24 am ((PST)) Delrin is one of the best, IMO. Hard enough to machine with good dimensional precision, soft enough to be easy to machine and act as a bearing. It also comes in several (expensive!) variants for different applications. Two of my favorites are glass-filled Delrin, used for making abrasion-resistant components like chain guides, and Delrin AF, a teflon- filled delrin that is basically self-lubricating. I use it for glides, sliders, and wheels. Neither is cheap, but most applications don't need much. I buy them through McMaster-Carr. Keep the Delrin AF cool while machining, since hot Teflon is a big problem (health hazard). For the glass filled material, take the same respiratory and machine precautions as if you were machining fiberglass, although it's much better in terms of machinability and surface finish. Michael ------- Re: New Mill [taigtools] Posted by: "Paul" pathfinder532003x~xxyahoo.com Date: Thu Dec 25, 2008 8:12 am ((PST)) Hi Kristin: Thanks for the info and the welcome. I have been very impressed by the friendliness of this group and how ready people are to help beginners like me. Only one other quick question for now, I want to mill cut-outs in plastic model railroad bodies. I know from drilling how easy it is to melt the plastic and end up welding rather than cutting. Any pointers to where on the web I can read up on choice of cutter and feed rates etc.? Paul ------- Re: New Mill Posted by: "greg.mcfaddenx~xxgmail.com" Date: Thu Dec 25, 2008 8:30 am ((PST)) My suggestion is to play with it, by hand. Until you get the physical feel for what your machine is experiencing, you won't really understand what the various sounds, chip sizes, etc really mean. And more importantly, find out what plastic it is. I've gotten decently good at cutting misc. aluminum alloys, stainless, and assorted plastics by playing with them manually first. Every plastic is a bit different, springs differently and therefore also requires slight tweaking of the code, depending on the tolerances. Also, the bigger the cutter (and the lower number of flutes) the better the chips clear but the slower (in/min) you have to run for a good finish. One part, for example: Noryl & Acetal run great at nominal and get me within a thou or so of what I want. So I made it out of UHMW, since I wanted to try something slicker and more abrasion resistant. Due to the flex of the UHMW, to get the tolerances and surface finish I wanted, I had to halve the step down distance and I had to move the bit 0.010 in towards the surface. (all dims in inches) If I run the UHMW code with UHMW, I get a good part. If I run the Noryl/ Acetal code with UHMW I get a part with a poor finish and 0.010 oversized on every surface (meaning 0.020 on the diameter). If I run the UHMW code with Noryl/Acetal, I get a good surface finish but a part that is 0.010 undersized on every surface (0.020 under on the diameter). I hope that is starting to make sense. One big trick, if you can deal with the mess... use an air jet to remove chips. Not only will it clear chips nicely but it cools the bit. Try to find out what they are made out of, buy a sheet or two from mcmaster.com or another supplier, and start cutting. Greg ------- Re: UHMW remnants - general [shopbuilttools] Posted by: "telecentric33" mbostonsprintx~xxearthlink.net Date: Mon Jan 5, 2009 9:45 am ((PST)) > it climbs drill bits like nothing I have ever seen if not clamped > or held securely. > I agree about the "climbing on drill bits" comment - I never drill > UHMW anymore without clamping it. Forstner bits seem to do a better > job anyway, A couple of notes: For work in plastics generally, especially those that are more brittle and/or tough, such as acrylic or polycarbonate, grind the cutting edge of the drill bit so the cutting lip is at a zero angle to the long axis of the drill bit. A correctly-ground drill bit will then act as a scraper in drilling the hole, rather than the standard helix angle pulling the drill bit into the material. If you choose not to modify the drill bit, then, as others note, clamp the material, preferably to a back-up block that allows drilling into virgin material behind the workpiece. UHMW is particularly bad because it is soft, and the drill self-feeds very easily, especially at the back side of the material. I would also note that the coefficient of friction of acetal (Delrin) is higher typically than UHMW, by roughly 50%. Delrin is a nice material to work with, for the reasons noted by other posters, but UHMW is more slippery by a healthy margin. Matt ------- Re: UHMW remnants - general Posted by: "eric.hagedorn" eric.hagedornx~xxhotmail.com Date: Mon Jan 5, 2009 9:57 am ((PST)) You're right on the numbers, Matt, according to the info I looked up. But, from experience, delrin slides a heck of a lot easier than UHMW. When I'm unpiling pieces from the boxes, UHMW will stay where I put it, while Delrin wants to slide right off. It's an absolute bear to pile it to any height. Anybody have any ideas why that is? ------- Re: UHMW remnants - general Posted by: "Bruce Bellows" bbellowsx~xxaci.on.ca Date: Mon Jan 5, 2009 12:01 pm ((PST)) If I might draw upon an similar scenario, when a printer piles a lift of paper for feeding into a printing press the paper also slides around very easily until the air is forced out from between the sheets. It could be possible the surface of the Delrin does not easily allow the air to escape thus acting like an air cushion between the pieces. If 2 flat pieces of Delrin are pressed tightly against one another will they still slide easily on each other? A handy product to have around the shop for a quick fix is UHMW tape which sells for about $11.00 for an 18' roll from Lee Valley Tools. Bruce ------- Re: UHMW remnants - general Posted by: "eric.hagedorn" eric.hagedornx~xxhotmail.com Date: Wed Jan 7, 2009 1:56 pm ((PST)) "Mosby West" wrote: > Please excuse my ignorance; but what is UHMW. Mosby UHMW is a polyolefin plastic, a form of polyethylene with extremely long molecule chains ( 3-6 million). Its full name is Ultra High Molecular Weight Polyehtylene, which is why we use the short form. Polyolefins are derived from oil - UHMW is a super, super dense form of wax (it smells like wax candles when it burns, but the drippings can cause 3rd-degree burns). It's a very slippery plastic, has little structural strength, absorbs virtually zero water (unlike Nylon, which can absorb up to 25% of its weight in water), very soft to machine (you can easily carve it with a knife), and is considered foodsafe. You can machine it with any woodworking tool. It's used in jig-making, robotics, as chain guides, as cutting boards, and so on - hundreds of uses. If you want to try some out, you can get assortments of various sizes and thicknesses from Lee Valley or Woodcraft. ------- Thread Cutting Attachment P/N 3100 question [sherline] Posted by: "veitchsp" veitchspx~xxyahoo.com Date: Sat Jun 27, 2009 3:22 am ((PDT)) I have a 4400 Lathe and I just fitted it with the 3100 Thread Cutting attachement. I tried cutting a thread, 18 TPI, in a test piece. The test piece was a 5 inch long piece of 1" diameter PVC. I was trying to cut an external thread but I noticed that as I advanced the bit 1 thousandth at a time towards the head stock, the PVC pipe was being pulled from the chuck. Therefore, the thread never cut correctly. I've tried on other test pieces and I've had the same problem. Does this make sense or is there a better way to chuck the material? Also, does sherline have a part number for a cutting bit for cutting an internal thread? Regards, Scott ------- Re: Thread cutting Attachment P/N 3100 Posted by: "Joseph Bautsch" joe.bautschx~xxgmail.com Date: Sat Jun 27, 2009 3:50 am ((PDT)) Scott - The material you chose for a test is too soft for the chuck to hold with the leverage the threading tool is applying. You will need to support the ends with the tail stock. Center drill the end of the rod and use a live center in the tail stock or in this case even a dead center in the tail stock should work. For the PVC you will need to turn two plugs for the ends. Slide one plug in the end to be mounted in the chuck. That will give you enough support for the chuck to hold. The other plug will need to be center drilled and leave a shoulder about the same diameter as the PVC on the same end. Insert the plug into the PVC so the shoulder butts against the end. Now you can use the tail stock with a dead or live center to support that end while threading. ------- Re: Milling styrene -- seeking opinions [sherline] Posted by: "rmcmanuslive" mcmanuslivex~xxcomcast.net Date: Thu Aug 20, 2009 8:35 am ((PDT)) I've milled a lot of styrene using the standard Sherline 2-flute mills and small mills from Microcut. I've never had a problem with melting or had a need to use lubricant. I use low to medium speeds and light cuts. The mills from Microcut are exceptionally smooth and leave a clean cut for small work (I build model trains). Bob McManus ------- Machining teflon or hdpe [atlas_craftsman] Posted by: "Bruce Freeman" freemab222x~xxgmail.com Date: Sun Sep 6, 2009 12:16 pm ((PDT)) I need a "slick" part, so I'm thinking of making it from Teflon or high- density polyethylene. Are there any special tricks to machining such plastics? Bruce NJ ------- Re: Machining teflon or hdpe Posted by: "Joe R" jromasx~xxcolumbus.rr.com Date: Sun Sep 6, 2009 12:29 pm ((PDT)) I don't know if there are any "tricks" but I've worked with hdpe and found it very easy. But the chips were stringy and wound up on the work. Joe R. ------- Re: Machining teflon or hdpe Posted by: "Barry Young" barryjyoungx~xxyahoo.com Date: Sun Sep 6, 2009 12:48 pm ((PDT)) Very high positive top rake as much as 20 Degrees on the tool bit will make a better finish. Barry ------- Machining teflon or hdpe Posted by: "rfmarchix~xxaol.com" Date: Mon Sep 7, 2009 5:33 am ((PDT)) My experience with Teflon was that it is very weak and deflects quite a lot under heavy cuts. If you want good control of final dimensions and finish, use high rake, high speeds and light cuts. It machines like butter... soft butter. ------- Re: Machining teflon or hdpe Posted by: "Richard Hughson" loopyrichx~xxyahoo.com Date: Tue Sep 8, 2009 6:36 am ((PDT)) I agree with the comments made so far. In final usage teflon, while very slick, is somewhat weaker and gives way more easily than hdpe under high loads or high speed wear. Rick ------- Re: Machining teflon or hdpe Posted by: "Norman Griffin" soveral36x~xxyahoo.com Date: Tue Sep 8, 2009 11:02 pm ((PDT)) I have had some improvements while machining plastics with an air coolant. I used a 1/4 inch copper tubing and an old paint regulator connected to my air supply. Pointing the tube close to the cut cools, stiffens and deflects the cuttings away from the work piece. Without the air, the cuttings (chips) have a tendency to melt and foul the work piece. ------- Re: Machining teflon or hdpe Posted by: "Richard Hughson" loopyrichx~xxyahoo.com Date: Wed Sep 9, 2009 4:57 am ((PDT)) That's a neat idea, thanks. In all the years I spent at work I cooled everything else in every way imaginable, oil, water, air, vortex tubes, etc. But I always turned plastic slow enough to not melt and just put up with it. Man, that strikes me as so funny right now. Thanks for the opportunity to laugh at myself, that's cool. Rick ------- Re: Machining teflon or hdpe Posted by: "Greg Bowne" gbowne1x~xxyahoo.com Date: Wed Sep 9, 2009 3:14 pm ((PDT)) What about UHMW, etc.? For sawing most plastics like Nylon 6/6, I use a FS Tool Non-Melting 10" tablesaw blade. It works very well. http://www.fstoolcorp.com They also have an outlet store http://www.fstooloutlet.com Their catalog: http://www.fstoolcorp.com/ecms.aspx/$fstool/FS_Catalogue.pdf Thanks, Greg Bowne ------- Re: Machining teflon or hdpe Posted by: "kd7brlrandy" kd7brlrandyx~xxyahoo.com Date: Fri Sep 11, 2009 1:07 pm ((PDT)) Once while turning UMHW rod, I had to stop often and untangle and remove the strings being cut off the rod. So, I rigged my shop vac to suck the strings as they were being cut from the rod. It worked quite well. Although I had to wear ear plugs because of the noise level of the shop vac. ------- Advice on Plastic [taigtools] Posted by: "Jack" tech.writerx~xxearthlink.net Date: Mon Sep 6, 2010 9:41 pm ((PDT)) In the continuing saga of my homemade audio amplifiers, I recently bought a few push switches and black plastic knobs for the front panels. The plastic knobs aren't very classy, so I machined an outer covering from 1/2" 6061 rod this afternoon. The thing is, the amplifier panel is aluminum, about 1/2" thick, and the knob can't be allowed to rub against it each time the switch is pushed. To prevent this, I want to install a plastic bushing from the back side of the panel and press it in flush with the back. It only needs to be about half the thickness of the panel to do its job, so I'll machine a shoulder in the panel (from the back) to act as a stop. I'm thinking this will need 1/2" or 3/4" plastic rod machined into a tube. The wall will be fairly thin, probably about .075", and the total length will be about .25-.3". What would be a good plastic to use for this? Iwa nt something that's easy to machine and won't crack easily, reasonably tolerant to heat (vacuum tubes in this gear), and won't mark the aluminum push knob over time. I have no experience working with plastics, so any advice will be appreciated. Photo of switch parts: http://jackandkelly.zenfolio.com/p939561350/e34475c81 ------- Re: Advice on Plastic Posted by: "Michael Fagan" woodworker88x~xxgmail.com Date: Mon Sep 6, 2010 9:56 pm ((PDT)) I'd use Delrin for this application. It's moderately expensive, but you don't need more than a foot for this project, and it machines extremely well and is stable over time. It comes in either black or white, with black being a little harder, white being a little softer and slipperier. You can get it in small amounts from McMaster Carr in any size you want. ------- Re: Advice on Plastic Posted by: "Ken Cline" clinex~xxfrii.com Date: Mon Sep 6, 2010 10:21 pm ((PDT)) You might consider teflon if you expect high temperatures (teflon is good to 260C, Delrin 110C). Otherwise acetal is nice to work with. I usually buy cut off pieces at my local plastics shop, but you can buy teflon rod by the inch at Online Metals (and probably other places). ------- NOTE TO FILE: The next conversation also discusses Delrin use, but might also do better with Teflon or another material depending on the temperature the part is subjected to. Lots of good plastic machining info. ------- Re: Machining Delrin bushings [sherline] Posted by: "lhbakeland" digitaltorquex~xxaol.com Date: Sun Oct 3, 2010 4:48 pm ((PDT)) "gene" wrote: > I need to make a set of bushings for a old motorcycle project that I have. It originally came with Silentbloc bushings which are no longer available. I was thinking of machining them a few thousands oversize and shrinking them in Dry Ice to get a pressed fit. I have never worked with Delrin and am a novice with a lathe. Any advice or good books on this subject? Thanks for any help. Gene Shatrowsky < It's easy. It cuts fast. Just use sharp tools. Use about 1300 rpm. Finish with sanding. Machining often makes striations. Leo ------- Re: Machining Delrin bushings Posted by: "R.L. Wurdack" dickwx~xxnwlink.com Date: Mon Oct 4, 2010 7:36 am ((PDT)) One of my sources says "Maximum working temperature = +180 F" for the white kind. Which flavor of Delrin do you propose using? ------- Re: Machining Delrin bushings Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Mon Oct 4, 2010 7:58 am ((PDT)) Hey Dick! Once you get squared away, lay in a supply of Hard Arkansas honing stones for HSS and diamond hand hones for carbide tooling. Sharp tools are a must with Delrin. Hone the cutting edges frequently (as needed) and carefully. Use a loupe and don't round over the edge(s). Semper Fi! Jerry G aka Sgt Glick USMC ( Ret.) 1951-1953 Korea ------- Re: Machining Delrin bushings Posted by: "Marcus" marcusx~xximplant-mechanix.com Date: Mon Oct 4, 2010 9:28 am ((PDT)) Hi Gene: Some things you need to know about your plan: First, plastics, including Delrin, creep when exposed to continuous force. This means that a press fit you establish during manufacture will not stay that way for any length of time. If you're relying on this to hold the assembly together you'll be disagreeably surprised and may cause a tragedy when the assembly fails. Evaluate your design very carefully and make absolutely sure the assembly will still work when the preload disappears, or better, eliminate it from the design. Mechanical retainers like snap rings may be needed in your assembly to prevent bushing migration. Second, there is no benefit to sanding the bushings if you machine them with a properly shaped cutting tool. Delrin machines extremely easily, as was pointed out, but the tools need to have a nose radius to prevent the appearance of hairlike burs on the finished surfaces. This radius need not be large; 0.005" is plenty to eliminate the burs. Third, in addition to creep, the material will distort during machining as the stress in the extruded bar is released when you cut bits of it away. To get the best roundness and dimensional accuracy, rough the part out all over (except for the last face you'll part off after the bushing is otherwise finished) leaving around 0.020" per surface for a finishing pass. Make sure you cut the blanks longer than you need for the parts so you have something to squeeze in the chuck without compressing the material you'll be turning into your bushing. Your bushing should terminate at least 1/4" from the tips of your chuck jaws; more if it's a big diameter bushing. You will have to accept a significant scrap stub, and by the way, when you drill the bore to rough size DON'T drill all the way through...you need a sold chunk to hang onto in the chuck. It can also be very helpful, to push a metal plug into the bore when finish turning the outside...especially useful if the bushing is thin-walled. Fourth, Delrin is hygroscopic, and will change dimension with changing temperature and humidity. It can move a LOT, so expect this and plan for it in your design. Fifth, many plastics, Delrin included, will drill and ream tight...by this I mean that if you ream a 1/4" hole through it, the resulting hole will be a couple of thou undersize and you'll find it too tight if you need a running fit on a nominal sized shaft. This is especially true if you make one of three basic mistakes: 1) Don't use a used reamer that's cut steel...it's too dull and will ream way undersize 2) Don't leave too little for reaming...you want the reamer to have enough to cut that it bites rather than just rubbing its way through the bore. 3) Don't run the reamer too fast...friction heat is not your friend. The correct way to finish these features is to bore them to size with a single point tool; this can be inconvenient when the bore is small, but it gives by far the best outcome. Cheers Marcus www.implant-mechanix.com ------- Re: Machining Delrin bushings Posted by: "Andy M" trumpy81x~xxoptusnet.com.au Date: Mon Oct 4, 2010 2:30 pm ((PDT)) GDay All, Gene, a better choice of material for bushings is a polyurethane material. Sorry, I have no idea what its commercial name is, but it is usually red in color and is machinable. It is available in sheet and bar of various sizes and it can be used to manufacture bushings such as shackle bushings and other components of vehicle suspension. I believe it is also used for skateboard wheels. If anybody knows the commercial name of the stuff I'm referring to, please chip in. Also, just out of curiosity, what motorcycle are you restoring? I have several old Triumphs in various states of repair. Regards Andy M ------- Re: Machining Delrin bushings Posted by: "Des" desbromilowx~xxyahoo.com Date: Mon Oct 4, 2010 5:12 pm ((PDT)) Gene, sharp tools, etc - everyone's told you that... I also use cooking spray ("Pam" I think it's called in USA) - basically the spray you use to stop food sticking to your frypan - canola/ rapeseed oil. The oil/ spray is a great lubricant/ cutting fluid for the delrin/ nylon/ HDPU range - reduces the "cling" of the swarf, and allows you to turn to a polished face. I used it for making rail buttons for MPR/ HPR several years ago, plus a few electrical bushings... came out looking like glass after turning. Des ------- Re: Machining Delrin bushings Posted by: "chieftoolmaker" chieftoolmakerx~xxearthlink.net Date: Mon Oct 4, 2010 5:39 pm ((PDT)) Just to add to the mix. Teflon bushings are the slipperiest/slickest I ever made. Not for motorcycles or anything like that. Jerry G ------- Uses for Dominos [sherline] Posted by: "minitool41" minitool41x~xxyahoo.com Date: Wed Dec 1, 2010 7:42 pm ((PST)) I have been exploring uses for dominos...Not ivory but "looking like ivory". You can find these new on ebay, new packages of up to 91 for $5 to $10. They are a relatively hard polymer of some type, but are quite easy to machine and polish. I find they respond well to a fly cutter or a standard carbide milling tool. (I don't know how they would cut with a carbon steel tool, but I don't think it would be a problem). They polish out nicely with fine sandpaper. I did some work today and obtained a very nice, ivory-looking finish using 500 grit paper followed with a 2000 grit Micomesh rub. The box I bought produces an old-ivory color. It is hard and dense. Very useful for decorative additions to projects. I have not put them on a lathe, but again I don't see a problem based upon the way they behave on the mill. Tips for buying dominos: First watch out for dominos that have a brass spinner inserted into the center. It limits the useability. Also, look for the largest dominos you can find. One ebay supplier sells a box of 91 tournament dominos, with no brass spinner, at a starting bid of $.99. I now have several boxes in storage and haven't paid more than $8 for any of them! Buy a box and you will find a challenge for a long, cold winters night. Perhaps a contest...What's the most unique application for an old domino? John Maki ------- Re: Uses for Dominos Posted by: "a3sigma" dcclark111x~xxcomcast.net Date: Thu Dec 2, 2010 1:12 am ((PST)) It's pretty likely that the dominoes are made of ABS -- one of the most commonly used of the engineering plastics. It has the machining and finishing properties you describe. see: http://www.mcmaster.com/#abs/=9yw7r7 Really wonderful stuff to work with. I'm about at the point of deciding to use it for everything that doesn't absolutely need to be from metal. David Clark in Southern Maryland, USA ------- Re: Uses for Dominos Posted by: "Tom & Judy Bank" trbank1x~xxverizon.net Date: Thu Dec 2, 2010 1:41 pm ((PST)) Take a look at: http://www.uilleann.us/imivory/ImitationIvory.htm Do it yourself in any size and shape you want. Great for making turned Christmas ornaments. (I started out by buying a rod of the stuff from a US woodturner's supply house for that purpose.) The problem I find is that there are a lot of suppliers for making this stuff in the UK, but not here in the States. I was told to check with boat shops for the UN 1866 Polyester Resin and catalyst, plus the Ivory pigment, but I'm not having a whole lot of success. Regards, Tom Bank ------- Re: Nylatron Backplates [atlas618lathe] Posted by: "Dean" deanwx~xxbmi.net Date: Thu Mar 3, 2011 3:01 pm ((PST)) "kimoleto" wrote: > Somebody has experience with them?? is this material capable??? > All comments appreciated I use nylatron for jigs and formers. It's a pretty sturdy material. Much on the order of a hard wood. I certainly would-not-use it for a backplate on a chuck, but it's fine for things like a jig plate that you would mount to a face plate or clamp in a vise. It simply does not have the structural integrity needed for a chuck back plate. ------- Date: Fri, 30 Sep 2011 09:17:53 -0700 From: "Cliff Rohrabacher, Esq." Subject: Re: [OldTools] Cutting Plastic /On 9/29/2011 2:31 PM, Robert Hutchins wrote: > At the risk of alienating the Highly Esteemed Galoots, I'm looking for > a good solution for cutting the plastic dividers in a fishing tackle > box. To keep the query on topic though, the tackle box was purchased > to keep my tools and supplies for chip carving. The box is a Plano > Guide Series with drawers permanently installed. (Plano also makes > them with plastic boxes that slip completely out of the boxes. This > is the other kind.) The dividers were molded when the drawers were > made and are, thus, permanent. They were sized for fishing lures. I > need to make some of them double or triple width to accommodate some > of the tools. > > I was thinking about some way to kill some electrons causing a wire to > heat which could then be used to melt the plastic. Perhaps this could > be done with a custom made soldering iron tip, but I've never done > that. I think Jim Thompson has posted about making his own tips for > his wood-burning tool. I've got several cheap soldering irons but no > wood-burning kit. > > Of course, cutting and grinding with a Dremel is also a possibility. > > Please pass the spittoon. I have Brasso and cloth. I promise to wash > my mouth out with the Brasso for mentioning electrons. > > Bob Hutchins The methods available to you are very much dependent upon the polymer you are working. Take plexiglass (methyl methacrylate) for example: It can be machined using conventional equipment. And circular saws made for that polymer but no matter what you have to stress relieve it or else the polymer will begin to "craze," which will soon turn into cracking, at the points of machining. So it's gotta be baked in an oven for 48 hours with a slow ramp down in temp. Polycarbonate is incredibly more forgiving. One can saw it, razor cut it, heat cut it and it seems to take it all without negative effect. Styrene is brittle and takes well to hot wire bending and cutting. Styrene is, interestingly, a prefect clean burning Fuel. It burns so cleanly that there is no pollution from it unless it's got additives then those may be issues, but pure styrene is pure clean fuel. Other polymers like polyethylene and polypropylene can be sawn, razor cut, hot wire cut with impunity. They tend to get a little stringy at the edges. They don't drill or mill up well tending to flex away from the cutters and return after the tool passes leaving a stringy mess. ------- Question for Anyone who knows: Plastics [sherline] Posted by: "Tom & Judy Bank" trbank1x~xxverizon.net Date: Fri Oct 21, 2011 1:18 pm ((PDT)) Can anyone tell me which is stronger, PVC or UMHW? I have an old Tonka fire engine, the big steel one with the cherry picker bucket and hose. Everything seems to be Ok except the I-Beam shaped part of the hinge for the lift bucket is broken. The original looks like it is cast PVC. Overall size is 1/2" X 1-1/2" X 1-1/4". I haven't been able to find PVC of that size. I have the UMHW and I have aluminum, both could be milled to the required shape (and either would be unaffected by water). I need recommendations, or if anyone could clue me on where to look for white PVC in a size close to that, I think that would be even better. Thanks, Tom Bank ------- Re: Question for Anyone who knows: Plastics Posted by: "Pierre Coueffin" pcoueffinx~xxgmail.com Date: Fri Oct 21, 2011 1:23 pm ((PDT)) I've had some luck splitting and flattening scrap PVC pipe, then laminating the sheets using solvent cement to make blocks. The tricky part is heating the plastic until it is flexible, but not enough to out-gas any chlorine. A well ventilated area is a good idea. ------- Re: Question for Anyone who knows: Plastics Posted by: "lhbakeland" digitaltorquex~xxaol.com Date: Fri Oct 21, 2011 1:39 pm ((PDT)) The original part is NOT probably PVC, it is most likely ABS or acrylonitrile-butadiene-styrene; a plastic very commonly thermosetteng used in plastic structual parts that are injection molded. Polyethylene, in any form, is too soft and too flexible for a structural part, like you want to make. My preference would be POM or poly-oxy-methylene. It is commonly sold under the Dupont "Delrin" trademark. It is widely available in white in sheets, bars and round rods. It is twice as strong as HDPE, self- lubricating, and very very stable. www.grainger.com stocks it in small quantities. Hope this helps, Leo ------- Re: Question for Anyone who knows: Plastics Posted by: "Tom & Judy Bank" trbank1x~xxverizon.net Date: Sat Oct 22, 2011 8:28 am ((PDT)) Ah, Leo, Just the information I needed. I have found a couple places within 30 miles that sell (and fabricate) plastics, so with this information (and the fire truck in hand) I shall see if they will open their scrap bin to me -- and point out the POM! Many thanks, Tom Bank ------- Re: Question for Anyone who knows: Plastics [sherline] Posted by: "RICHARD WIECKOWICZ" tmdlbearsx~xxyahoo.com Date: Sun Oct 23, 2011 7:34 am ((PDT)) Discovered a great web site ( tapplastics.com ) with about 20 short videos on cutting, molding, gluing plastics. Not sure how much of their product is available outside the western states. ------- NOTE TO FILE: An interesting conversation took place in the SherlineCNC group at Yahoo titled "Helicoils -- from tooling plate thread" starting Sat May 12, 2012 and it can be found here in the Threading (Lathe and Otherwise) text file in the Metal Lathe Files section. The conversation does indeed provide some interesting and useful information about tooling plates and helicoils, and briefly goes into the matter of products that can be used for tooling (or backing) plates to hold work. Some materials like MDF or ABS plastic when cut or machined have safety implications that are briefly discussed. You would be well advised to do more research and take adequate safety precautions when using these and other substances. ------- Bakelite [myfordlathes] Posted by: "peterscott147" pjscottx~xxsky.com Date: Sun Jun 10, 2012 11:51 am ((PDT)) My son has acquired a bakelite centre which contains the horn push for the steering wheel of his split-screen VW van. Unfortunately it is 3.5mm too large in diameter. He has asked me if I can 'turn' it down to size for him. Is it possible to turn bakelite? The edge which needs to be turned is quite fine and I do not want to spoil it as it is quite valuable. I can hold it OK in my three-jaw but what is the best method of removing the 3.5mm from the diameter? Any ideas? Peter ------- Re: Bakelite Posted by: "Kevin" tadpolex~xxbtinternet.com Date: Sun Jun 10, 2012 2:00 pm ((PDT)) So, since it is too large it isn't the "correct" item for that wheel. If you turn it down it instantly loses all the value that you mention. A dilemma of some sort! Kevin, NW England, UK ------- Re: Bakelite Posted by: "David Littlewood" davidx~xxdlittlewood.co.uk Date: Sun Jun 10, 2012 11:57 am ((PDT)) You could try attaching it to a small faceplate (slightly less than the finished diameter) with turner's cement. David Littlewood ------- Re: Bakelite Posted by: "Marc Holzer" arcus42x~xxyahoo.com Date: Sun Jun 10, 2012 12:30 pm ((PDT)) I wouldn't try machining bakelite at all as it contains asbestos. As a consolidated lump bakelite is quite safe but machining it or filing it or abrading it in any way (even just snapping or smashing it) will liberate asbestos fibres which if inhaled could cause major, potentially fatal respiratory problems. I would leave it be. ------- Re: Bakelite Posted by: "Robert Mitchell" rmm200x~xxyahoo.com Date: Sun Jun 10, 2012 3:01 pm ((PDT)) Do you have a reference for that? Bakelite (a phenolic resin) has used a number of fillers, most commonly flour. I can find no reference to asbestos ever being used. Robert Mitchell ------- Re: Bakelite Posted by: "David Littlewood" davidx~xxdlittlewood.co.uk Date: Sun Jun 10, 2012 3:11 pm ((PDT)) > I can find no reference to asbestos ever being used... The only reference I have seen is one in Wikipedia suggesting it was used as a filler in the heat shields of some Soviet space rockets. Hardly likely in a car pooper. David Littlewood ------- Re: Bakelite Posted by: "Frank Erskine" frank.erskinex~xxbtinternet.com Date: Sun Jun 10, 2012 4:31 pm ((PDT)) Likewise, I've never heard of asbestos used as a filler for bakelite. I'm a little into preservation and renovation of bakelite telephones, and have only heard of flour and/or wood dust used. Perhaps some specialist applications of bakelite did use things like asbestos. I should imagine that turning of bakelite would be quite stressful to the cutting tool; probably carbide tipped tools would be most appropriate, followed by steel wool, then some sort of wax "polish". It may be that the filler prevents a proper finish being obtained. Of course if the only machining is to the outer edge of a button, a glossy finish may not be too important. There's a firm, Fairgrieves Mouldings Ltd (or something like that!) http://www.compressionmoulding.co.uk/ that used to produce bakelite mouldings in those halcyon days. It might be worth trying to contact them, despite their change of premises, and possibly key staff, some 20 years ago. Frank Erskine ------- Re: Bakelite Posted by: "Cliff Coggin" clifford.cogginx~xxvirgin.net Date: Mon Jun 11, 2012 1:36 am ((PDT)) Absolute rubbish! This is typical of the nonsense spread by the ignorant and the gutter press who have lost all contact with reality. Cliff Coggin ------- Re: Bakelite Posted by: "Alistair Campbell" campbell_alistairx~xxyahoo.com Date: Mon Jun 11, 2012 2:23 am ((PDT)) Cliff Actually it's not absolute rubbish Asbestos WAS used as a filler in SOME bakelite products along with woodflour and a number of other materials. You can't tell by looking if a Bakelite item contains asbestos, and given that people have been machining the stuff for years with no cited specific risk there is PROBABLY little danger, I assume because the asbestos even in powdered/ground/machined Bakelite will be complexed with the resin itself, which would render it safe. That does not mean snorting a couple of lines of powdered Bakelite in 80's coke fashion or indeed breathing loads of the stuff if machining it would be a good idea, but then we all use dust masks for all dusty work don't we!!! >From a restorer of old telephones, with over 30 Bakelites in the collection. Alistair ------- Re: Bakelite Posted by: "Frank Erskine" frank.erskinex~xxbtinternet.com Date: Sun Jun 10, 2012 4:47 pm ((PDT)) On Sun, 10 Jun 2012, Paul Kennedy wrote: >Well as a collector it should not be touched as it was never intended for the model of van you're trying to fit it to. A purist would not want a collectable to be altered at all. By doing so you decrease its value. < That depends on what you count as "value". If it's purely monetary return that's one thing. Some people however gain great satisfaction from making something do a particular job as a personal "achievement". Or even just fun. Frank Erskine Sunderland ------- Re: Bakelite Posted by: "Andrew Curl" methuselahx~xxntlworld.com Date: Sun Jun 10, 2012 12:55 pm ((PDT)) Its perfectly possible to turn bakelite, but it is brittle, so you must be careful. Turning the o/d would be best acheived by a "peg and pusher" here; that is something turned to fit inside the bore, held in the headstock chuck, and with something like nylon, pushed from the tailstock to give a drive. If things do go wrong, my Father has a '66 split bus, a workshop, and a fancy aluminium steering wheel- he may well have a spare. He's back off holiday in the next week or two. Email me directly for his email address; as an aside, he's the chap to talk to about eberspacher heaters - now is the time to fit one, i.e. summer! Andrew UK ------- Re: Bakelite Posted by: "Stephen Black" black19650x~xxo2.co.uk Date: Sun Jun 10, 2012 1:01 pm ((PDT)) This may sound silly but could you turn the wheel instead? Steve ------- Re: Bakelite Posted by: "peterscott147" pjscottx~xxsky.com Date: Mon Jun 11, 2012 1:33 am ((PDT)) Many thanks to you all for your helpful replies. My son's transporter van is a very early example, 1952, so genuine original parts are difficult/impossible to find. The correct steering wheel centre for his van would cost circa £200 IF you could find one. The part he bought cost him £65. Externally it looks the same but the diameter is 3.5mm too large and the internal part has been butchered but it is still useable with a little fettling. So we are not changing its value by doing a little more work on it. Finding another one in any condition would be very difficult. I have mounted it OK in the three-jaw. But considering your replies, I will use the tailstock to hold it in the chuck so I do not have to tighten the jaws too much and will pack the jaws with some softish material. I have decided that trying to `turn' it is too risky. So, my current thinking is to mount my mini-drill on the cross slide with some form of abrasive wheel in it. I have an old bakelite door knob which I can practice on, to find the best abrasive. Once again many thanks for your replies. Peter ------- Re: Bakelite Posted by: "Pete W." enwodex~xxyahoo.co.uk Date: Mon Jun 11, 2012 5:16 am ((PDT)) Hi there, all, I agree with Alistair, not specifically about Bakelite, but about asbestos being used as a filler in moulded plastic parts. I can remember seeing asbestos mentioned as a filler in specification of the moulded plastic bodies of some connectors used in the electronics industry. What I can't remember was which particular plastic was involved - it might have been melamine or polyethylene terephallate (try saying that with a mouthfull of half-chewed crisps!!). Best regards, Pete W. (aka 'Enwode') ------- Re: Bakelite Posted by: "Alistair Campbell" campbell_alistairx~xxyahoo.com Date: Mon Jun 11, 2012 5:43 am ((PDT)) Hi Pete, Thinking about it, back in the 'old days' they used Asbestos for just about everything, for example does anyone remember the rawlplug powder you mixed with water called 'Rawplastic'? people used to make the stuff up by chewing it - how is that to make you shudder? It was considered a 'wonder' material years ago, as so often is the way only latterly were the full facts know - bit akin to Radium, they put that stuff in everything including cough sweets, and how about xrays - Clarkes use to have xray machines for your feet in their shops.. kids used to play on them!!! Of course modern "elf and safety" has its drawbacks - like if you want to use a Yankee screwdriver you are meant to wear a face mask, implement an exclusion zone and warn low flying aircraft, and we won't even mention all the stuff kids are not allowed to do in school engineering classes any more... Al ------- Re: Bakelite Posted by: "Marc Holzer" arcus42x~xxyahoo.com Date: Mon Jun 11, 2012 5:18 am ((PDT)) Cliff, many thanks for your clearly informed response to my "gutter press" derived ignorance. I would be very grateful if you could assist my education a little further by indicating exactly where my error lay. Are you saying that asbestos has never been used as a constituent part of bakelite? That machining bakelite cannot liberate asbestos fibres? Or that mesothelioma cannot be caused by asbestos fibres? This would help me to identify which parts of the "gutter press" (the Health Protection Agency and the HSE among others) I should avoid in the future. ------- Re: Bakelite Posted by: "Alistair Campbell" campbell_alistairx~xxyahoo.com Date: Mon Jun 11, 2012 5:57 am ((PDT)) Marc, Asbestos was used in some Bakelite it was just a cheap filler, along with many other things - so if a given piece of Bakelite has Asbestos in it no one knows without microscopic analysis. Asbestos DOES cause mesothelioma even the gutter press can't deny that. Then again some denied that AIDS was a virus! The asbestos dust or fibres in bakelite or other resins are PROBABLY well bound and coated even if the material is machined so the dust PROBABLY doesn't constitute the same risk as raw fibre. HOWEVER does anyone want to risk it? treat it like brake dust and wear a mask, - then even if it's a hazard you don't expose yourself., and if it's not you are just wearing a mask as you always should when doing dusty work. For what its worth diluted PVA glue is used to emulsify asbestos dust and render it safe, if you need a way to clear up any suspect dust. Rgds Al ------- Re: Bakelite Posted by: "c j.s" callinicus1953x~xxyahoo.co.uk Date: Mon Jun 11, 2012 5:41 am ((PDT)) Hi Guys, If I remember correctly, from my medical physics days some 40+ years ago, the problem with asbestos is that the fibres have a barbed shape. It is this barb that gets caught in the lung tissue and stays there, the body surrounds it with scar tissue and you can't breathe through scar tissue, hence the problems. If Asbestos is used as a filler in a resin material, which is then machined, could it be that the resultant dust created "sheaths" the barbs and reduces the likelihood of lung problems? As to whether the resin dust itself can cause one of the myriad of other lung diseases I cannot comment on. I would say that a suitable dust mask is highly recommended when working with any dusty materials and the use of a filtered dust extractor can help to keep your workspace clear. CJ(UK) ------- Re: Bakelite Posted by: "Bob Hamilton" bobx~xxhamilton-bob.freeserve.co.uk Date: Mon Jun 11, 2012 5:43 am ((PDT)) Now Now Boys. Mind you I did get a smile out of this and it does sometimes need someone to “get things going” on a site that could become very mundane and quite boring. Seconds out??????? Bob ------- NOTE TO FILE: This thread might still go on for a bit but I think all the useful stuff for me has been said and I am tuning out. Whether there is asbestos or not, please do take proper health and safety precautions for any dusty task, or when you are in any dusty environment. When one brother in the TV show Supernatural asked the other what the plan was, he simply replied: "Don't die." Pretty wise advice. And then in July we hear that Peter has succeeded. Bravo. ------- Re: Bakelite Posted by: "peterscott147" pjscottx~xxsky.com Date: Sun Jul 15, 2012 12:41 pm ((PDT)) Well I finally got round to doing this job. I have an old bakelite door knob in the garage so I tried turning that taking fine cuts at a slow speed. and it worked Ok. So I mounted the horn push in the three jaw and turned the edge down to size one thou at a time. (Perhaps I should call this scraping rather than turning.) So the job is now done. Thanks for all your input, Peter ------- Re: Corian Question... [taigtools] Posted by: "Peter Homann" groupsx~xxhomanndesigns.com Date: Tue Oct 30, 2012 5:07 am ((PDT)) On 30/10/2012 12:13 AM, Mars Bonfire wrote: > I was always concerned about milling or turning Corian because I thought I understood it contains some type of mineral (stone) that could load the ways with abrasive. Was my understanding correct? < Hmmm, something to ponder. I do a lot of cutting in Corian on my Taig. http://www.homanndesigns.com/index.php?option=com_content &view=article&id=60:tm20vl-mill-cnc-conversion&catid=34:cnc-pro jects&Itemid=55 http://www.homanndesigns.com/index.php?option=com_content& view=article&id=62:tm20vl-mill-cnc-conversion-part-2&catid=34:cnc-pro jects&Itemid=55 http://www.homanndesigns.com/index.php?option=com_content &view=article&id=63:tm20vl-mill-cnc-conversion-y-axis-part-3&cat id=34:cnc-projects&Itemid=55 Cheers, Peter Homann eStore: http://www.homanndesigns.com/store Web : http://www.homanndesigns.com ModIO - Modbus Interface Unit email : peterx~xxhomanndesigns.com DigiSpeed - Isolated 10Vdc I/F Phone : +61 421 601 665 TurboTaig - Taig Mill Upgrade board ------- Re: Corian Question... Posted by: "Will Schmit" anchornmx~xxyahoo.com Date: Tue Oct 30, 2012 4:02 pm ((PDT)) I did some thinking about the presence of abrasives in the material. I just got 10 really nice granite-colored pieces the other day. I realized that 90% of what I mill into finished parts is ivory colored corian. It doesn't have any "chips" in it. The stuff with the chips, I use for fixtures. A lot of what I do would be considered "art" (by those with a sense of humor). The ivory colored corian makes perfect accents to "steampunk" kinetic sculpture. I use luscious hardwoods, lots of brass, home-made gears, and fake ivory parts. The ivory looks like it is 100 years old (and not 21st century counter top), if it is made in multiple parts. The parts are soaked in strong coffee for 7 to 40 days, and the variation in "stain" makes it look like REAL ivory. Sometimes I add a kicker of Transtint Mission Oak dye. Anyway, I haven't noticed a huge amount of abrasive wear, but it might be a function of the selection of corian. ------- Re: Corian Question... Posted by: "Peter" groupsx~xxhomanndesigns.com Date: Tue Oct 30, 2012 6:39 pm ((PDT)) Also, a couple of observations I found when Milling Corian: 1. Corian cuts like a hard plastic. The chips are also similar, that is that they are quite large. As such I believe that the abrasive "stone" is captured in the chips and does not end up as an abraisive dust. That said, tool wear may be an issue but I haven't found it excessive. All the parts that I cut were mainly done with a 4mm high helix solid carbide bit designed for acrylic. 2. Unlike a lathe, the Taig Mill ways are quite well protected from swarf and chips. And the chips are too large to get between the ways. As such, apart from toolbit wear, I don't believe cutting Corian presents a wear issue on a Taig mill. Cheers, Peter Homann http://www.homanndesigns.com/store ------- Re: Corian Question... Posted by: "Ken Cline" clinex~xxfrii.com Date: Tue Oct 30, 2012 8:22 pm ((PDT)) ATH, the mineral component of Corian, is essentially non-abrasive. Its Mohs hardness of 2.5-3.5 can be compared to steel at 5.5+ and anodized aluminum at 8+. It might eventually polish the brass/bronze gibs, but I have a hard time imagining any harm from this. As always, frequent cleaning of the ways is a good idea. ------- Re: Corian Question... Posted by: "frxdyx~xxaol.com" Date: Wed Oct 31, 2012 2:03 pm ((PDT)) OK.... I got a reply from Dupont. The first line is my question to them: "Is Corian dust abrasive? Should I worry about the dust damaging the polished rails on my CNC machine?" The next is their reply: "The Corian dust is not abrasive, however it does absorb oils on equipment. So it should be wiped off and apply lubricants as recommended by the machine manufacturer." ------- new article: Low Cost Plastic Insulating Washers [atlas_craftsman] Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Sun Jan 27, 2013 4:37 pm ((PST)) This article is intended for those new to our hobby. It details how to use punches and scrap plastic gift cards to make insulting washers. If you are interested, please see: http://rick.sparber.org/hpw.pdf Your comments and questions are welcome. All of us are smarter than any one of us. For the full index of my articles, see rick.sparber.org. Rick ------- Re: new article: Low Cost Plastic Insulating Washers Posted by: "speedphoto300" speedphoto300x~xxyahoo.com Date: Sun Jan 27, 2013 5:24 pm ((PST)) > punches and scrap plastic gift cards to make insulting washers. I don't put up with washers insulting me, they go straight into the trash if they do. ------- Re: new article: Low Cost Plastic Insulating Washers Posted by: "Rick Sparber" rgsparberx~xxaol.com Date: Sun Jan 27, 2013 5:29 pm ((PST)) I sure fat fingered that one! Rick ------- Re: new article: Low Cost Plastic Insulating Washers Posted by: "Paul DeLisle" ferretpdx~xxgmail.com Date: Sun Jan 27, 2013 6:49 pm ((PST)) Umm. Rick. I think you have a *serious* issue here! Speaking as someone who has worked with these for *decades*..You're forgetting a major point: The *SHAFT* of the screw/bolt is not insulated as it goes through the metal body of the box! Now.you could "tighten it down real tight", and *hope*.but that's not very reasonable, now is it? In order to properly insulate a "through-screw" from either a transistor (where I normally see such things), or a metal box (as you have it shown), you need what's called a "shoulder washer", or a "top-hat washer." This type of washer will hold the screw in the center of the hole.even if the "shoulder" doesn't go all the way through. Hope this helps! Paul DeLisle ------- Re: new article: Low Cost Plastic Insulating Washers Posted by: jerdalx~xxsbcglobal.net Date: Sun Jan 27, 2013 7:10 pm ((PST)) Yep..... One does indeed need the top-hat washers. http://www.mcmaster.com/#shoulder-spacers/=l849zb JT ------- Re: new article: Low Cost Plastic Insulating Washers Posted by: "Clem Wixted" cwixtedx~xxgmail.com Date: Sun Jan 27, 2013 8:28 pm ((PST)) I think Rick covered this in his article by saying: "I used a plastic washer on each side and a 1/4" diameter washer inside the box wall." It's good to emphasize the need for this insulation in the pass through hole. ------- acrylic [atlas_craftsman] Posted by: "Bruce ." freemab222x~xxgmail.com Date: Wed Jan 30, 2013 10:55 am ((PST)) Have you any experience working with clear acrylic? I need to turn a part from clear acrylic, then polish it to transparent again (not optical quality, just transparent). Can you recommend cutting and polishing techniques? ------- Re: acrylic Posted by: "william_mcbride_sr" billx~xxcasemodman.com Date: Wed Jan 30, 2013 11:08 am ((PST)) If you want to turn acrylic just make sure your tooling is very sharp. You can sand it down from 220 to 400 or 600 being wet to get pretty clear. Then if you need clearer, buff it with a buffing wheel to get as close to optically clear as possible. ------- Re: acrylic Posted by: "Guenther Paul" paulguenterx~xxatt.net Date: Wed Jan 30, 2013 11:11 am ((PST)) You can use some real fine sand paper start with 500 grit and then go finer; for the final finish you can use a good quality car wax on a rag and bring it back to a clear position. I have used a car buffer and car wax and removed scratches from acrylic sheets. Just make sure you don't get the acrylic hot, but warm is ok. You can also try the product that is sold in auto-part stores to polish Acrylic headlight covers. Have fun GP ------- Re: acrylic Posted by: "Sam Rod" mail4samx~xxgmail.com Date: Wed Jan 30, 2013 11:40 am ((PST)) Bruce, Look into Flame polishing. Very gratifying, quick and easy when done right. I used to sit and sand/polish, and still do on occasion for certain projects; but mostly I now Flame polish -- most of the pros do the same. Regards, Sam ------- Re: acrylic Posted by: "trenchcoat_willy" jdconnelx~xxgmail.com Date: Wed Jan 30, 2013 11:57 am ((PST)) Yup. Sharp tools, and lots of fine sanding. For what I do, I take it from 400-600-800-1000 then wet sand at 1500 and 2000. Then move to a polishing wheel setup, and finish it with a buff of carnuba. Probably much more than you'll need. ------- Re: acrylic Posted by: "william_mcbride_sr" billx~xxcasemodman.com Date: Wed Jan 30, 2013 11:50 am ((PST)) Depending on the job will determine a flame polish. No waxes or polishes can ever be used if you flame polish it. And depending on the part, you will see crazing over time. Much sooner on a part that is handled a lot. ------- Re: acrylic Posted by: "a8050266" mail4samx~xxgmail.com Date: Wed Jan 30, 2013 3:11 pm ((PST)) I agree with WMS. Although, I say do a small test. Take three lengths of Acrylic -- can all be the same length. Flame polish Lightly, Medium, then Over flame; label them FP Light, Medium and Over respectively. Then also take a piece and polish it using any means but without flame. Nail them to something outdoors with the greatest amount of sunlight (easy for me because I'm in florida). It will be months; perhaps in a year you might "MIGHT" see some difference. You will be glad you did this almost effortless test. I will say a acetylene torch with a fine tip works the best for me. ------- Re: acrylic Posted by: "John Mooney" jwmooney41x~xxyahoo.com Date: Wed Jan 30, 2013 5:00 pm ((PST)) Acrylic polishing. I suggest one visit a dental prosthetics lab. Denture bases are polymethyl acrylic. After curing in a hot water bath the denture is high polished using different grades of pumice and proprietary acrylic polish. ------- Re: acrylic Posted by: "Jon Elson" elsonx~xxpico-systems.com Date: Wed Jan 30, 2013 6:15 pm ((PST)) Cut with a very sharp tool at fairly high speed, take light cuts. It will make a lot of highly charged confetti that is a royal pain. Breathe on the confetti to momentarily neutralize the static charge so you can control the stuff and see what you are doing. Polishing with toothpaste works, but jeweler's rouge and similar polishing compounds work faster. There are also special liquid polishes for plastic that work even better. Jon ------- Re: acrylic Posted by: "printeronretainer" printeronretainerx~xxyahoo.com Date: Wed Jan 30, 2013 6:19 pm ((PST)) Greets: I've shaped a lot of acrylic on my lathe. Yes, sharp tools and polishing technique work. I'll just add that: 1) Get a set of drills, end mills, and routers designed for acrylic. Especially the drills. They cut like butter and won't crack the acrylic. They save money quickly by protecting the work from surprise disasters. Don't accidentally plunge cut this stuff! 2) I've often been told that the best coolent/lubricant for acrylic is good ol' water if you need it. It works. 3) Special tools and information are available from http://www.tapplastics.com/product/supplies_tools/plastic_tools_sup plies/tap_plasdrill_bits/161 The home site has tons of videos on how to shape and work with plastics. The sections on casting plastic resins could be of use to you, too. Have a blast. Rob Sacramento, CA Makes mechanical electro-static generators. ------- Re: acrylic Posted by: "Guenther Paul" paulguenterx~xxatt.net Date: Thu Jan 31, 2013 1:22 am ((PST)) The Outfit selling drills for plastic, boy oh boy they are selling a bill of goods. The way a drill is sharpened is the answer. GP ------- Date: Fri, 9 Aug 2013 13:37:35 -0700 (PDT) From: Thomas Conroy Subject: [OldTools] Cutting old plexiglass? I presume its possible; but does anyone have any tips? Toothcount? Rip or crosscut? Will it help to tape the line to be cut? How much will it dull the saw? We have a salvaged sheet to protect my grandmother's sideboard top, so I can use it as an auxiliary binding bench. Tom Conroy ------- Date: Fri, 09 Aug 2013 16:43:22 -0400 From: Anthony Seo Subject: Re: [OldTools] Cutting old plexiglass? I'd say metal cutting saw or a handsaw with a very large TPI. Depending on the thickness it might be a real lesson in aggravation. > Will it help to tape the line to be cut? Yes...back in the days of Jr High shop we did some projects with plastic and always taped before making any cuts (band saw). >How much will it dull the saw? Good possibility and I think I would use a newer saw rather than an older one to lessen the chance of breaking teeth. I really don't think it's a good idea but..... Tony Olde River Hard Goods http://www.oldetoolshop.com TSMusic on Facebook http://www.facebook.com/tonyseomusic ------- Date: Fri, 9 Aug 2013 15:47:38 -0500 From: John Holladay Subject: Re: [OldTools] Cutting old plexiglass? Tom, I've cut the stuff with a power saw, but not by hand. On a table saw, I used a combination blade with 40 teeth and it made a good cut. When you buy the stuff new, it has a nice plastic sheeting to protect it from scratches and prevents any major mishaps with the edges such as chipping. That said, it definitely would not hurt to use masking tape or similar on the cut lines. If cutting with a hand saw, I really don't know. My experience in cutting anything plastic has been that a hack saw does better than a wood saw. I'm not sure how you would use a hack saw for this. John Holladay 205-229-8484 ------- Date: Fri, 9 Aug 2013 13:52:05 -0700 From: Ben Belzer Subject: RE: [OldTools] Cutting old plexiglass? Depends on the thickness, but I've cut it with a utility knife. Deep scoring, then put the scored area over a bench edge and tap with a mallet. Ben B ------- Date: Fri, 09 Aug 2013 16:52:29 -0400 From: William Ghio Subject: Re: [OldTools] Cutting old plexiglass? Get one o those hacksaw blade holders that capture about half the blade and leave the rest projecting free of the frame. Don't know what to call them but any hardware store should have one. Bill ------- Date: Fri, 09 Aug 2013 20:54:25 +0000 (GMT) From: "Adam R. Maxwell" Subject: Re: [OldTools] Cutting old plexiglass? Tom, We used to cut this with a tablesaw, usually a 60-80 tooth blade if I recall correctly, and you have to watch your feed rate to avoid burning it. Bandsaw works too (especially for tube/cylinder stock), but the cut isn't as clean. New cast acrylic sheets have a sticky paper backing on them, but we never bothered taping edges when cutting older stuff. YMMV. A tailed jointer makes a very nice edge after the saw cut, and it's also razor sharp (DAMHIKT). After jointing and assembly, we'd use a flame to smooth the jointed edge and give it a glassy look, but that takes practice. My suggestion: use a fine toothed crosscut saw (11+), and be prepared to sharpen it afterwards. Be careful around the edges during and after cutting, make sure it's well-supported when cutting, and use a light touch on the saw to avoid chipping or spalling. I'm not sure if you can edge joint it with a handplane, but you could certainly use a file or rasp. hth, Adam ------- Date: Fri, 9 Aug 2013 13:57:15 -0700 (PDT) From: Thomas Conroy Subject: [OldTools] Re: Cutting old plexiglass? Oops! "With a handsaw" is assumed. The plexiglass sheet is 1/4" thick. Pass over that spitoon. Tom Conroy ------- Date: Fri, 9 Aug 2013 17:01:12 -0400 From: Ed Minch Subject: Re: [OldTools] Cutting old plexiglass? We built our sailboat in the late 70's and bought surplus 3/4" plexiglass from the Rohm and Hass plant in Bristol PA - 4 X 8 feet and IIRC, about 100 pounds. It was older when we got it. We used band saws and routers, and hand saws, planes and chisels (rip teeth worked best on the hand saw) and noticed only a little wear on any tools. Usually it was band saw and block plane. The material is much softer than Lexan. This spring, we had to replace a piece and used a scrap from that same original chunk, now 35 years older, and did not notice any differences in working it. We never taped the cut, but most of the time there was a paper backing - probably a good idea. Ours had an extra hard surface on it. Good luck Ed Minch ------- Date: Fri, 9 Aug 2013 22:14:47 +0100 From: Steve Licence Subject: Re: [OldTools] Cutting old plexiglass?? I would use one of my "Eclipse" sheet metal saws. -------- Date: Fri, 9 Aug 2013 17:11:10 -0500 From: Wesley Groot Subject: Re: [OldTools] Cutting old plexiglass? Tom, if it's thin like 3/16 or less, scoring and snapping is the easiest fastest and cleanest way to do a straight line break. It melts at a low temp, so use a heavy Stanley type knife and use a lot of pressure. If it's thicker, a crosscut will work better than a hacksaw because the hacksaw tends to stick in its own kerf. Come to think of it, a low angle of attack and some paraffin on the blade will help too. Good luck. Wes ------- Date: Fri, 9 Aug 2013 15:20:18 -0700 (PDT) From: Jim Parker Subject: Re: [OldTools] Cutting old plexiglass? I did not read all the others posts so do not kill if redundent but there is a special inexpensive hooked cutter just for plastics usually for sale next to the glass cutting station at the borg. I use it on acrilic and plastic "veneers". ------- Date: Fri, 9 Aug 2013 15:41:51 -0700 (PDT) From: Thomas Conroy Subject: Re: [OldTools] Cutting old plexiglass? The deed is done! [organ chord] I used an 11-point (10 t.p.i.) "& Sons" D-23 panel saw, reasonably sharp. I had a 45" x 51" piece to cut into two pieces at least 21" wide. I taped the top and marked it (actually, Terry had that already done) and cut in from each end, raising it from time to time to check the quality of the cut. The overhand cabinetmakers' ripping method proved to work best for me. The cutting was no slower and no harder than cutting a piece of plywood, and seems to have dulled the blade no more than plywood. No need for a hacksaw. When the uncut gap was about a foot long I raised the sheet to look at the bottom and it broke across the gap, the break leaving a sort of tooth running about 3" into one side of the sheet. Reasonable success. The worst problem is that I got a bunch of cracks a couple of inches long running at ten to thirty degrees to the line of the cut. I think they happened when I twisted the saw, or if there was too much vibration. These won't matter in the intended coarse use, but they would be a problem for fine work. I figure I'll run some CA into them to keep them from getting worse. I could try cutting the cracked area off, it's in waste, but a couple of inches of overhang at the back won't be a problem and I don't think it is worth the trouble. I now have a piece 51" x 22-1/2" to cover a 65" x 20" sideboard top. I'll trim off the big "tooth," file the edges to make them less sharp, and cut a 22-1/2" x 14" piece from the waste to cover the end of the sideboard top. I may try the score-and-snap method, or at least score the cutline to prevent premature breaking. Many thanks for all who offered suggestions, all of which were good for context and some of which were vital, especially cutting with a fine- toothed saw and a light touch. I'll finish it up when I get over the current lung congestion and bruised or cracked rib. Tom Conroy Berkeley ------- Date: Sat, 10 Aug 2013 08:54:00 -0400 From: "Cliff Rohrabacher Esq." Subject: Re: [OldTools] Cutting old plexiglass? Plexi and actylic are trade names for Methyl Methacrylate. It is s funny stuff. The older it is the more likely it is to cause problems when stressed. It resists UV like a trooper being able to stand out in the sun for way far longer than any other polymer I can think of. But it is stress sensitive. Machining methyl methacrylate induses stresses that have to be relieved by annealing. The annealing process is to heat it to some temperature (which I forget) and to hold it for a period and then ramp that temp back to normal over a period -- both times I also forget. If it is not annealed the stresses manifest as cracks and crazing in not too long at all. The table saw blades one uses for plexi should be high rake ground to reduce heat buildup. Other tools can be use normally but it is always best to flood the area of the cut with coolant during machining. Failure to do so will result in excessive heat and excessive stress and often burning. Poly Carbonate [aka Lexan] can be UV stabilized with a coextrusion or a surface treatment. Poly Carb is way far easier to work than plexi; it does not need to be annealed after machining; it does not burn so easily either. It is more flexible too. ------- Atlas 10" change gears [atlas_craftsman] Posted by: "dlclark66" danx~xxdcdetec.com Date: Wed Sep 18, 2013 6:58 am ((PDT)) I was missing a few change gears for my Atlas 10" Pic O Matic lathe so I decided to try to draw them out and print them with my 3D printer. I used Taulman3D.com 618 nylon for the material since it is kind of self lubricating and stronger than PLA for a gear application. It turned out so well that I created STL files for all of the change gears and printed them. I've placed these STL files on Thingiverse for anyone who might want to print their own gears. The Pic O Matic uses most of the standard 10" Atlas gears so there may be one there that you need. I hope someone finds them useful. You can find them here http://www.thingiverse.com/thing:143893 ------- Re: Atlas 10" change gears Posted by: anthrhodesx~xxaol.com Date: Thu Sep 19, 2013 7:43 pm ((PDT)) dlclark66 (???), downloaded the files out of curiosity. I don't have a 3D-printer nor a larger Atlas lathe so they aren't of any use to me but I'm curious about several things. You appear to have a 20 without keyways but no 20 with keyways. You have 24 tooth 20 PA, for what? You have another 24, what PA and with or without keyways? You have two 46s and two 48s, the significance of which I haven't sorted out. You have no 54. You do have 32, 36, 40, 44, 50, 52, 56, 60, and 64. There are other gears which would be useful, 21, 63, 37, and 47 are useful for inch-metric conversion, as is 34 combined with 36. 38 is useful for 19 TPI. Depending on how difficult it is to generate the files, it might be useful to include all numbers from 20 through 72 (80, 100, and 127 might be a stretch). How did you generate these files? Are they true involutes or circular approximations? How difficult would it be to do the same for 24 DP gears as used for the Atlas 6" lathe? Can you do gears with altered pitch diameters? I'm CCing a copy of this message directly to you, I'd be interested in some discussion off group. Anthony Berkeley, Calif. ------- Re: Atlas 10" change gears Posted by: "Doc" n8as1x~xxaol.com docn8as Date: Fri Sep 20, 2013 7:27 pm ((PDT)) > You have two 46s 46 T is the "stndrd" gear for 11-1/2 tpi pipe thrds on many older loose change lathes ...used for IIRC 11/2 in & other pipe thrds....although i cut a 23 gear to use w/ compounding since i did not have a 4in disc of cast iron ......why two ? dunno .... best wishes doc ------- Machining G10 (Tufnol like material) [myfordlathes] Posted by: "Phil Tuck" philx~xxhvtesla.com Date: Wed Nov 20, 2013 12:56 pm ((PST)) All, Does anyone on the group have experience of machining G10 (a glass resin based material). If so I wondered if they had any tips. I understand dust is a problem, and the stuff is hard on tools (Ordinary Tufnol being like butter in comparision) Would HSS be up to the job? Cutting fluid, parrafin, light oil, WD40?, Spindle speed? It will be for turning an 8 inch disc (using a faceplate in the gap) on a S7. Regards Phil T www.hvtesla.com ------- Re: Machining G10 (Tufnol like material) Posted by: "PETER ROACH" peterroachx~xxbtinternet.com Date: Fri Nov 22, 2013 2:41 am ((PST)) Phil, G10 is NOT like Tufnol, it is a glass cloth based material like FR4. Normally drilled and routed, rather than single point turned. The latter trend to be cut at very high spindle speeds (low feed per rev) and use of air coolant. You'll want a shop vac, respirator, goggles, etc. HSS will work, but blunt quickly, Carbide better and diamond coated better still, depends how much you need to machine. These materials are used in the electronic industry so it's worth picking up some industry specific tooling and router rather than turning. A couple of good threads on Practical Machinist. Regards Peter ------- Re: Machining G10 (Tufnol like material) Posted by: "Phil Tuck" philx~xxhvtesla.com Date: Mon Nov 25, 2013 12:04 pm ((PST)) Thanks for the reply Peter. I only mentioned G10 was 'like' Tufnol' because someone who didn't know it, may have thought it was a rare alloy or something. I had already been told by someone who had used it that he ruined HSS tools, but as he is not that used to lathe work I thought maybe he was doing some wrong. It is to be used for a high speed spark gap, where a 10 inch rotating disc has Tungsten electrodes that conduct high voltage, and the G10 has far superior electrical insulation properties over Tufnol. Since then further research has made me go back to Tufnol as the preferred material as the machining (routing is not an option) of G10 is just too much hassle. Regards Phil T www.hvtesla.com ------- Craftsman lathe chuck shield [atlas_craftsman] Posted by: ksierensx~xxmsn.com Date: Mon Jan 20, 2014 2:27 pm ((PST)) Just finished a shield for my Craftsman 101.21200 (mk2) lathe and wanted to share. It was the first time I bent any Plexiglas, but it was really easy. Just made a form out of 3 2x8's and heated it up to 350° for about 5 minutes. I also bent up a smaller one for a shield on my mill. I made the bracket so it resembled the carriage stop, and made it so that the shield could be removed by just pulling out the pin. I also realized that I could use it as an indicator mount, so I added a 1/4"x20 threaded hole on the top of the bracket. The smaller shield can also be clamped to the lathe shield to extend the coverage. When I was figuring out what size to make it, I made it so it would also fit around the spindle of my Benchmaster mill, but when I added the side piece, I realize it would not work on the mill. Well I guess that means I will have another project to make one for the mill too! 7 of 7 Photo(s) http://groups.yahoo.com/group/atlas_craftsman/attachments/fol der/1224830893/item/list sheild bracket 2.png sheild bracket 3.png sheild bracket 7.png sheild bracket 4.png sheild bracket 5.png sheild bracket 6.png sheild bracket 1.png ------- Re: Craftsman lathe chuck shield Posted by: "James Irwin" jirwin1x~xxaustin.rr.com Date: Tue Jan 21, 2014 9:19 am ((PST)) FWIW Plexiglas is acrylic, and not very strong. Less expansive eyeglass lenses are made of acrylic, and are not effective as safety glasses. Lexan is polycarbonate and quite a bit more rugged. Shatter resistant safety eyeglasses are made of polycarbonate. Just a heads up for future such projects. Jim ------- Re: Craftsman lathe chuck shield Posted by: noddazx~xxyahoo.com Date: Sat Jan 25, 2014 4:58 am ((PST)) Very nice! After I had set my lathe up I wondered about metal shavings dropping onto the motor. Scott ------- Can an 'auger' be cut with Sherline CNC lathe? [SherlineCNC] Posted by: grangerroadsx~xximonmail.com cornbeltroute Date: Thu Aug 7, 2014 6:50 pm ((PDT)) I'm fiddling around with a manually operated injection molding machine concept. A key element of almost all modern commercial plastics injection machines is a plasticating screw. The screw body is narrower at one end to allow plastic pellet feeding; in the middle it enlarges to compress the pellets and melt them; at the other end the screw body is large to further process the pellets. Here is a link to a photo of a plasticating screw: http://www.xaloy.com/Files/Products/EasyMeltInjectionScrew.jpg Forget the injection nozzle (pointed tip), considering just the shaft and flutes, can such a shape be cut on a Sherline CNC lathe? (I have a CNC 4400 but have never used it; great first project, huh?) Thanks for any suggestions or advice you'd care to send, much appreciate it. Brian Chapman Cedar Rapids, Iowa ------- Re: Can an 'auger' be cut with Sherline CNC lathe? Posted by: "Andy Trivette" trivettex~xxcharter.net tool_and_die_maker Date: Thu Aug 7, 2014 7:12 pm ((PDT)) I have built some small injection molds in the past. I did not use a screw to feed the pellets in. I machined a barrel out of stainless and made a plunger like goes in a needle from the Dr.'s Office. I held the mold together with a c clamp, positioned it under an arbor press or use the quill on mill to put pressure on the plunger. I used watt low heater bands to heat and thermo couples control the heat of the barrel once the plastic got molten. I use the arbor press to force the material down the barrel into the mold; not great for production but for 30 or so parts at a time it is easier than having an injection press and takes up very little room in my tool box Andy Trivette Trivette’s Gunsmithing Tool and Die Maker CSP plastics ------- Re: Can an 'auger' be cut with Sherline CNC lathe? Posted by: "Hannu Venermo" gcode.fix~xxgmail.com hvenermo Date: Fri Aug 8, 2014 1:17 am ((PDT)) Easily. No. ? Why It's easily doable on any cnc lathe .. IF you have cam software that can write the code. Or if You can write the code yourself using any programming language (MS Office would work). Looks like a single grooving tool would do it (unless the root radius is critical). Easy answer: You need cam for lathe. Likely any cam should do it, imho. Doing it in steel will likely take a long time, but should not present too many other problems. You might need a moving steady, with a bushing to support the screw on the crests (will bend and bow from tool pressure otherwise). Depending on your controller, a (very) short parametric program could also likely work. Linuxcnc supports parametrics, conditionals and variables, and so does mach3/4. It might need programmer logic on mach3, due to mach3 not supporting if/then, if you wish for three distinct sections/shapes. Programmer logic: IF a=0, then sectionnr=1 can be done as sectionnr= 1 x (a=0) IF-then can be written mathematically in functions and is a great way to make fast, tight reliable code. It may or may not be easy to understand & support later - depending on programming language, style and skills. ------- Re: Can an 'auger' be cut with Sherline CNC lathe? Posted by: jowhowhox~xxyahoo.com jowhowho Date: Fri Aug 8, 2014 1:50 am ((PDT)) That would be easy on a mill with a rotary table. If you want to be stubborn and use your lathe, you could use a stepper driving the headstock spindle and a secondary spindle milling on the cross slide. The programming would be simple, with a couple G01 moves doing all the work. A "straight line" interpolation with two linear axes and a rotary axis gives you a spiral helix, or a helical spiral. I have a stepper head and use it for threading and knurling with a standard lathe tool bit. Works great, but there is very little torque. I have a fairly large stepper on the spindle, and I think I need to increase the drive cog ratio for more torque. Must have more torque. I've managed to cut course threads over 2" in diameter in brass. ------- Re: Can an 'auger' be cut with Sherline CNC lathe? Posted by: grangerroadsx~xximonmail.com cornbeltroute Date: Fri Aug 8, 2014 4:59 am ((PDT)) Andy, Hannu, Jowhowho I are a simple country boy ;-) I'll have to find a way to interpret your 'machine foreign language' to understand what you're saying. But, if I get the jist of your comments, cutting a plasticating screw can be done. Correct? So, what I have to figure out now is how to do it. My CNC setup uses Vector CAD/CAM to create tool paths from AutoCAD art, and Flashcut hardware/software to generate code and run the machines. This setup should get it done, if I understand your statements. If you don't mind, I might have a few more questions as I move along in my attempt to figure out how to do this machining. (Previously, I've only used the mill; have never before used the lathe.) Jowhowho, I can't envision making such a cut on a mill, my machining experience is too limited. I have a Sherline rotary table but it's manual. I understand it can be converted to CNC use with the addition of a stepper. Andy, I've been studying plastics injection molding textbooks. My aim is to replicate the actions of a vertical shuttle injection molding machine for production of model railroad flex track in an obscure scale. Manual operation (with some semi-automatic features, perhaps using Flashcut X,Y,Z software to make certain moves) is the goal. Thanks much! Brian Chapman Cedar Rapids, Iowa ------- Re: Can an 'auger' be cut with Sherline CNC lathe? Posted by: "Elizabeth Greene" elizabeth.a.greenex~xxgmail.com Date: Fri Aug 8, 2014 11:37 am ((PDT)) Yes, that part can be made on a manual lathe very very very slowly by offsetting the tailstock for the taper and by cutting it as a 1 TPI screw with a custom cutter. The reason it will be slow is the large number of passes to cut the "thread". With a manual machine a human being is going to have to start the cut, let it go 20 rotations, stop the cut, move back to the start, Repeat. Repeat. Repeat. Our small lathes have materials-and- physics-imposed limits on depth of cut, so you'll have a lot of passes like this to finish it. You could probably make it faster by setting up the lathe for screwcutting and using a toolpost mounted grinder instead of a regular cutter. Turn the headstock by hand and let the grinder make it in one or two (very long) slow passes. Finally it can be made many orders of magnitude faster on a cnc mill with a rotary axis by shimming one side of the rotary axis (for the taper) and slaving the horizontal and rotary axis together. HTH ------- Re: Can an 'auger' be cut with Sherline CNC lathe? Posted by: greshamx~xxmediavisual.com wentbackward Date: Fri Aug 8, 2014 4:38 pm ((PDT)) Hi Brian, To cut the screw on a CNC lathe you need a spindle encoder (or more simply with Mach3 just a single pulse that marks top dead centre). You can use a feedrate that is proportional to the rotation. So instead of mm per minute you use mm per revolution. Seeing as you have the machine, I'd throw some plastic stock on there and give it a shot. These are not easy things to design, but certainly fun to play with. Obviously the professional screws are patented, made to extremely tight tolerances and very very high quality surface finishes. How important is that well, take a look at what these guys are achieving with use of an auger bit: Lyman / Mulier Filament Extruder V5 by hlyman - Thingiverse http://www.thingiverse.com/thing:380987 Personally I would have never thought it could work, too high friction, etc. Regards Paul ------- Large CNC lathe at CNC ws??[SherlineCNC] Can an 'auger' be cut with Posted by: "William Thomas" wthomasx~xxgfn.org tmw5763 Date: Fri Aug 8, 2014 12:16 pm ((PDT)) Hi Brian: Didn't you have a large CNC that the worked on to get the tool changer working at the last CNC workshop? If this is your machine you could easily cut the screw if you program in a lot of cuts. You really don't have to worry much about the thread as they have used just straight plunger machines for many years and still do. Just cut the same high lead square thread a number of times. Offset the tool in "Z" after you get the thread to depth in the first position. Also, if you just cut it deep enough to handle a pellet it may work OK if you use it to just feed the pellets and keep them near the heated barrel and use the square end of the plunger as a ram to push the shot into the mold. Since you are running low volume just a straight plunger should do. It just takes longer to heat a shot of plastic. GOD'S BLESSINGS Bill Thomas ------- Re: Large CNC lathe at CNC ws??[SherlineCNC] Can an 'auger' be cut w Posted by: "Elizabeth Greene" elizabeth.a.greenex~xxgmail.com Date: Fri Aug 8, 2014 3:34 pm ((PDT)) I have the Dave Gingery Plastic injection molding machine book. It does not use an auger. It uses a lever operated piston to drive the plastic into the mold. Would that be easier? Elizabeth Greene ------- Re: Large CNC lathe at CNC ws??[SherlineCNC] Can an 'auger' be cut w Posted by: "Hannu Venermo" gcode.fix~xxgmail.com hvenermo Date: Sat Aug 9, 2014 3:50 am ((PDT)) Easier-yes. Today, most stuff is best built as a combo of bought and made stuff. The plunger is best bought - as you can get ground hardened polished plungers much better than most can make (at any cost), for very cheap. In mold stuff, for example, hardened pins are precision ground, and cheap. Locating pins-same. Dowel pins are same thing. A precision ground piece might have 2 microns TIR. Most cannot make stuff equal to or better than that. hanermo (cnc designs) ------- Injection molding machine??[SherlineCNC] Can an 'auger' be cut with Posted by: "William Thomas" wthomasx~xxgfn.org tmw5763 Date: Fri Aug 8, 2014 4:08 pm ((PDT)) HI Elizabeth: It sure will work and be easier to build. The straight plunger machines go way back to 60's. They take a little longer to heat the plastic and may not mix it up as much as a screw but they sure do work. I once helped move a 1,000 ton (clamping pressure) machine the molded shipping pallets. It had appox 5 foot square platens that it clamped shut with just one BIG cylinder. It had a screw style plunger but the 75 ton machine we moved with it was just a straight piston type. The two instructional small units I have had both use the straight plunger. Look at some of the units they have for your drill press or mill and they are straight plunger machines. GOD'S BLESSINGS Bill Thomas ------- Date: Fri, 8 Aug 2014 15:36:23 -0700 From: Kermit Perlmutter Subject: Re: [OldTools] Old Stove Question... Wood heat http://books.google.com/books/about/Wood_Heat.html?id=kfLmAAAAMAAJ No complete manual on restoration but a well written book on all aspects of heating with wood. Does cover what to look for in a used wood stove. ------- Re: Can an 'auger' be cut with Sherline CNC lathe? Posted by: grangerroadsx~xximonmail.com cornbeltroute Date: Sun Aug 10, 2014 7:14 am ((PDT)) Elizabeth, thank you for your suggestions, much appreciated. What I'm hoping to do requires larger shots, which means higher clamping forces than available with manually operated machines. I've been studying industry manuals that, I hope, will help me cobble together a manual/semi-automatic machine that can get the job done. This machine would be basic principles at work, not a commercial machine with extravagant bells and whistles. Bill, you've got injection machine experience? Wonderful! You can build a machine for me, right? ;-) I'm worried about the clamping force I might need. I'm working in 1:120 scale, and the largest railroad model body I would mold would have a mold surface area of about 32 square inches (not including sprue and runner surfaces). Could be I'm looking at needing 100 tons of clamping force. . . . And, I'm thinking a two-stage injection system (a non-reciprocating screw that mixes and melts the plastic and deposits it into a chamber where a plunger then rams the plastic into the mold. Paul, the video link you provided to the extruder is highly helpful. Thanks much. Hannu, I will look first at purchasing parts before attempting to cut anything at home on the mill or lathe. You're right, of course, why re-invent the wheel when a wheel can be purchased from Firestone or Goodyear at a reasonable price? My concern was the cost of a screw and barrel, but I should have priced these components before asking for machining help here. I did, however, learn from the responses I got. PPE (Plastic Process Equipment) is a large distributor of all things injection molding, and I'll look there before attempting to cut parts I'll require to move ahead with my project. Thanks, everyone! ------- Machining Tufnol Hints [myfordlathes] Posted by: "Phil" pipx~xxhvtesla.com philiptuck Date: Thu Aug 14, 2014 6:30 am ((PDT)) All, I found this http://www.directplastics.co.uk/popular-topics-tufnol/tips-about-mach ining-that-dusty-stuff.html May be helpful to somebody one day, Regards Phil Tuck www.hvtesla.com ------- Machinable Plastics [sherline] Posted by: "Matt Goodman" goodman312x~xxyahoo.co.uk Date: Wed Oct 1, 2014 4:56 pm ((PDT)) Hello folks, While shopping for materials for other purposes, I started looking at plastics for the purposes of building turning and milling skills. Based on the descriptions on the vendors website, it appears Acetal and UHMW have good machining characteristics and material stability. Thoughts on these or similar materials? I'll need to break out my beginners books again to find feeds and speeds recommendations. My cutting tools are (for now) limited to HSS lathe tooling and two flute cutters. Thanks, Matt Goodman Columbus, OH ------- Re: Machinable Plastics Posted by: dcclark111x~xxcomcast.net a3sigma Date: Wed Oct 1, 2014 5:23 pm ((PDT)) Hello Matt, I use a lot of ABS plastic. See mcmaster.com for a large selection, fair prices, and fast delivery. Biggest caution: plastics have very poor thermal conductivity and low melting point. Heat of machining builds up quickly and doesn't dissipate. Coolants are messy and don't help much anyway. Trick is low speeds and fast feeds = big chips. Sharp HSS tooling, and remove material quickly. Best, David Clark in Southern Maryland ------- Re: Machinable Plastics Posted by: procterx~xxihug.co.nz kwstse Date: Wed Oct 1, 2014 7:54 pm ((PDT)) Hi.Matt, David about covered it! - turning: very sharp tools. Reduce speed until any sign of melting disappears. Deeper cuts than metal. - milling: very sharp cutters. Reduce speed.... I use double sided tape for holding plastic sheet down, in conjunction with metal clamps. Greg.Procter, Hukerenui, New Zealand. ------- Re: Machinable Plastics Posted by: "Pat B" patbutlerx~xxcomcast.net appraisalservices2000 Date: Wed Oct 1, 2014 10:41 pm ((PDT)) Also, plastics are subject to changing their dimensions quite a bit when they get hot. Have to let things cool down before you take measurements. Pat ------- Re: Machinable Plastics Posted by: "Trevor Cuffy" trevor_itqx~xxyahoo.co.uk Date: Thu Oct 2, 2014 1:46 am ((PDT)) Thanks for sharing the info Matt, Delrin and PTFE are other easy to machine materials. Regards Trevor ------- Re: Machinable Plastics Posted by: "Wolgamott M" mnwolgamottx~xxyahoo.com Date: Thu Oct 2, 2014 6:03 am ((PDT)) Acetal and Delrin are different suppliers but same material; it holds tolerances very well and cuts like a dream. Your work will look professional as a novice. M. Wolgamott ------- Re: Machinable Plastics Posted by: "Matt Goodman" goodman312x~xxyahoo.co.uk Date: Thu Oct 2, 2014 9:43 am ((PDT)) Thanks for all the replies on materials and cutting. I've ordered two types of Delrin (copolymer and homopolymer) and some UHMW for starters. Matt Goodman Columbus, Ohio ------- Re: OT: Machinable Plastics Posted by: gidleymx~xxnrm.qld.gov.au mike.gidley Date: Thu Oct 2, 2014 8:13 pm ((PDT)) No one mentioned Machinable wax. You can buy or make your own. http://www.instructables.com/id/Machinable-Wax/ ------- Re: Machinable Plastics Posted by: chieftoolmakerx~xxearthlink.net glicker31 Date: Fri Oct 3, 2014 12:57 am ((PDT)) Hi Matt, due to my longevity (and age), I have milled (and turned) every plastic there is. I concur with my friend and partner, Dave. I would like to add that the use of is a good solution (pun intended) to the coolant/lube application. Water soluble, can be thinned to any desired consistency. Long shelf life. No commercial connection. Jerry G (Glickstein) ------- Re: Machinable Plastics Posted by: "lawrence schneider" larry.schneider3x~xxverizon.net Date: Fri Oct 3, 2014 6:54 am ((PDT)) Jerry, So, based on your experience, what is the best plastic for milling? Thank you, larry ------- Re: Machinable Plastics Posted by: chieftoolmakerx~xxearthlink.net glicker31 Date: Fri Oct 3, 2014 9:49 am ((PDT)) Hi Larry, this might sound like a copout, but it really depends on your application. During my occupation, I was given prints with the plastic stipulated. And dimensional parameters..... Best is what you have on hand..... :) Jerry G (Glickstein) ------- Re: Machinable Plastics Posted by: procterx~xxihug.co.nz kwstse Date: Fri Oct 3, 2014 10:22 am ((PDT)) Hi, Plastic is a relatively fragile material in human hands. The real question to ask is "does any available plastic have the qualities that my finished project will require?", followed by "why would I use plastic when metal would be better?" There are situations where milled or turned plastic has more appeal than metal or wood, but once you have the specs for a variety of plastic materials you find that the choice of suitable plastic types approaches one. For example, ABS machines well but one wouldn't use it for bearings, unless perhaps you are making a tiny solar powered model windmill that will only ever revolve a hundred turns in it's lifetime. Engineering plastics are better but you won't be buying a piece large enough to mill a coffee table! Greg.Procter, Hukerenui, New Zealand ------- Re: Machinable Plastics Posted by: baboonhead11x~xxyahoo.com baboonhead11 Date: Thu Nov 27, 2014 4:08 pm ((PST)) Delrin (or similarly acetal) is good for machining. It has fairly good dimensional stability and rarely damages or dulls the tool unless you make a mistake like taking super deep cuts or ram the tool into the workpiece. The downside is it stinks when you machine it with too much material removal rate that generates a lot of heating of the plastic. Oh and delrin is quite expensive. It's actually even cheaper to use aluminum alloys like 6061. Acrylic (or PMMA) is good too, although it has a low melting point so lots of coolant is necessary while taking lighter cuts. Actually UHMW is considered one of the worst plastics for machining because it is so resiliant as a material. It's good for certain applications because of this property, but it means if you don't have the world's sharpest tool, it will burr like crazy, leave lots of machining marks, poor surface finish, and doesn't hold dimensions very well. Not the most fun plastic to machine. My personal favorite in terms of creating the best looking parts is delrin. Then I like acrylic because it's cheap. ------- Help for a newb [TAIGTOOLS] Posted by: marksichermanx~xxgmail.com mark_james_1960 Date: Tue Dec 2, 2014 5:14 pm ((PST)) Hi, and thanks in advance. If this post was on reddit I'd label it ELI5 (explain it like I'm 5 years old). I'm new to Taig lathes - actually to lathes in general. I've turned some bowls and pens but that's about it. I've got my Taig lathe set up (for metal) and I've done some basic mucking around getting used to it. At the moment I'm trying to make some cribbage pegs. The material I'm working with is Corian - a solid surface countertop material that cuts beautifully - like green wood or aluminum if you're not familiar with the material. To prepare the pegs I cut a 1/2" x 1/2" x 1 1/4" piece of corian, drill an 1/8" hole lengthwise in it for 1" of the length (so I don't see the metal on the top), sand a piece of 1/8" stainless rod, coat it with crazy glue, insert it into the corian and then mount it to the lathe in a 3 jaw chuck. I leave enough of the stainless rod sticking out the bottom that I can mount it in the 3 jaw held by the stainless rod. I want to make a fair number of these pegs so I'm trying to come up with a way that isn't too arduous. The top 1/2" or so is a 1/4" cylinder with a few grooves in it. From below the 1/4" cylinder to the bottom it tapers down to 1/8" so it can insert into the board. I'm going to leave the bottom bit bare metal. There's a picture on the Lee Valley web site of something similar to what I'm trying to make but theirs are made of wood or metal. http://www.leevalley.com/en/images/item/woodworking/projects/41k0510s1.jpg Turning a number of these will quickly become an arduous task so I'm trying to simplify matters. To that end I took a piece of a reciprocating saw blade and filed the negative of the profile into it. I then sharpened the edges of the profile and mounted it in the cross slide. I shimmed it up so that the cutting edge is just below the centerline. My intention was to slowly feed it into the spinning blank with the cross slide and cut the entire profile in one go. The thing is that this doesn't seem to work. It chatters or scrapes along but doesn't cut well. After a time it will overheat the Corian which makes it all flexible. I've tried this bevel up, bevel down, and with a flat profile like a scraper. None of them works well enough to make this practical. Any suggestions on how I can efficiently accomplish this would be very much appreciated. Thanks! Mark ------- Re: Help for a newb Posted by: "Max Cato" maxsthekatx~xxyahoo.com maxsthekat Date: Tue Dec 2, 2014 8:57 pm ((PST)) Hi, ELI5 eh? Reddit infiltrates the group... Just as long as it isn't /r/gonewild we'll be ok. I'm not an expert at using lathes, but I'm almost certain that what you're doing with that negative won't work. That negative doesn't have a cutting edge on the bottom. So, as the material comes up, it's just rubbing along the tool, instead of being cut away like a regular tool would do. The friction from this rubbing is what is causing your material to heat up and deform. Or, to put it another way, there's a reason lathe tools are cut the way they are :) You need a cutting edge. Check out this guy's videos (and he has tons more) to see how to make your own in high speed steel, or you can just buy pre-made ones from online retailers: https://www.youtube.com/playlist?list=PLD77A1FAB10795E34 This means your approach won't work, and you'll need to either grind a special tool out (which sounds like it might be fairly complicated), get a CNC lathe which you can program with a computer, or just suck it up and spend the time with your machine. This is where a radio/tv/cd player in the shop comes in nice. Max ------- Re: Help for a newb Posted by: "Pat Goodyear" kf6pbnx~xxgmail.com kf6pbn Date: Tue Dec 2, 2014 9:03 pm ((PST)) Mark, While I am not by any means a skilled machinist I have done similar repeat cuttings. First, the cutting tool needs to be at the center of the material, not below; if it is below, the work will tend to climb up the face of the cutting bit. Second, the cutting edge is not sufficiently backed up, the tool face needs very rigid, and to be thicker say a 1/4 inch or so. I would suggest you buy a cheap wood chisel, or a thick plane iron, a file may also work, but you would have to detemper it to shape it then harden it again, grind the shape on it and position it correctly and try it again; keep the minimum amount extended beyond the tool holder. A standard HSS bit may also work with the pattern ground into the side of it; make sure you put the proper relief on the underside. Mert may have a better example. Pat ------- Re: Help for a newb Posted by: "Ed Fred" edfredfred1x~xxfrontier.com karlh_1 Date: Wed Dec 3, 2014 5:06 am ((PST)) You might consider holding the 1/8 stainless in a 1/8 collet instead of the 3-jaw. Less run-out may give less chatter. If you end up using a standard cutter, you could make the task less arduous by making a spacer to use between the carriage and the carriage stop to make it easy to space the grooves evenly. (I use a set of feeler gauges - ganging 4 or 5 blades to get the required spacing.) If you don't move the tool post, you could knock out the whole set with minimal effort. For the 5 year old: These pieces are small enough you could mount 2 tool posts on the carriage - set one to face off and one to cut the grooves. Mount each piece in the same way - perhaps placing the corrian right against the jaw or collet - then face off the end with a cutter on the back side carriage. Without moving the carriage, lock it in place. Extend the carriage stop rod until it is near the carriage, then place your first spacer between the stop rod and the carriage, advance the stop rod until it is tightly against the carriage, then lock the stop rod. Now, advance the carriage until it is against the stop rod, lock the carriage in place, and cut your first groove with the second tool. Make a note how far you advance the cross slide so you can repeat each groove to the same depth. With the carriage still locked, loosen the stop rod, back it off the amount of your second spacer. Tighten the stop rod, loosen the carriage and advance it to the stop rod, then tighten the carriage again, and cut your next groove. Measure once - cut a hundred times. When it come time to cut the taper, you could use the same method, except use either the head stock or the tail stock as your reference and an adjustable t-square for your spacer. Chuck up the first piece so it is held in a good spot, set up your taper cut, but before you make the first cut, set the adjustable t-square to mark the piece's starting location. That way, you will not have to mess with the carriage position after the first piece is cut. And remember, you are doing this for fun and diversion - Lee Valley only wants a buck and a half for each pin. ------- Re: Help for a newb Posted by: "Jake Horky" jacob.horkyx~xxgmail.com jakehorky Date: Wed Dec 3, 2014 5:48 am ((PST)) I think the concept of your original method is legitimate (possibly called a "form tool"), but you might have to make it out of a thicker piece of real tool steel in order to get the proper cutting reliefs and to make it stiffer. I'd consider making up a pattern duplicator. I've seen pictures of folks who've done this on their Sherline lathes. Here is one neat example: http://plsntcov.8m.com/Duplicator.html Best of luck to you! ------- Re: Help for a newb Posted by: "David Beierl" dbeierlx~xxattglobal.net dgbeierl Date: Wed Dec 3, 2014 8:08 am ((PST)) I'm with Ed Fred on this. Re the form tool, I don't think you're going to get it to work because of rigidity, or lack thereof. But the heating could be caused by insufficient front relief so that the tool is rubbing; or that the tool simply can't exert enough pressure on the flexible workpiece to bite. Metal turning is a brute-force exercise and requires the machine and workpiece to resist considerable forces without deflecting. Further remarks below. >The material I'm working with is Corian This is probably not an issue, but be aware that Corian is somewhat abrasive even when it shows a sheen - not surprising as it's about half epoxy and half rock dust. I made a lovely pocket from it once to hold and transport a bronze container (actually an Orthodox pyx) I was working on; and I had to stop using it as it was scratching the bronze. >To prepare the pegs I cut a 1/2" x 1/2" x 1 1/4" piece of corian, >drill an 1/8" hole lengthwise in it for 1" of the length... Is all this just to chuck the thing, or do you actually want the s/s embedded in the pin? If it's for chucking I doubt that an inch and a half out it's going to be rigid enough. The Atlas _Manual of Lathe Operation_ aka MOLO says for small work no more than four to five diameters extension from the chuck, and at that to use short and light cuts, which a form tool is the very backwards of. My suggestion would be to forget the s/s, make the Corian long enough to chuck it and use a tailstock center, turn the piece between the two with the pointy end to the right; then remove the center and part off the waste at both ends. Also, are you by any chance talking about a single form tool the entire inch and a half length of the piece? I don't think there's any possibility of getting such a long tool to work on this tiny lathe, make the tool itself never so rigid. MOLO, talking about (admittedly light-weight) ten- and twelve-inch lathes, says max 1/8" width in steel, half inch in brass and aluminum. I'm not at all confident that my six-inch Atlas would handle a half-inch tool even in aluminum. Two techniques that can help with chatter or hogging in are a) using a tool upside down at the rear, so that cutting pressures cause the tool to tend to unload instead of digging in; and b) use of a gooseneck/spring type toolholder which deliberately becomes the most flexible point in the path between tool and lathe bed, and allows the tool again to spring away from the work - see http://www.practicalmachinist.com/vb/antique-machinery-his tory/more-spring-tools-208588/ >piece of a reciprocating saw blade and filed the negative of the >profile into it. I could see having a rear toolpost with a tool containing just the two ribs (assuming Lee Valley pattern). Set your compound for the taper angle, turn to diameter using cross slide then taper with the compound; then come in with the form tool to make both grooves at once. Yours, David Beierl ------- Re: Help for a newb Posted by: desbromilowx~xxyahoo.com desbromilow Date: Wed Dec 3, 2014 2:36 pm ((PST)) Mark, you are describing a "form tool" - and they can have broad cutting surfaces which increase chatter (what you're describing) Rigidity (created by reducing movement or vibration in the tool, mounting, etc) will help, but you can also consider reducing the cutting width by "breaking " the tool into 2 pieces. Imagine cutting the "handle" part of the cribbage peg in one movement, and cutting the tapered section in another movement - those will reduce the cutting length of the tool by roughly half, and that will help reduce chatter. If I was doing this task, I'd also look to see what I could do to make the stock easier to manage... do they make corian rod? - or can you turn your corian sheet into rod? (cut into square strips using a jigsaw, and then using a 4 jaw chuck, or split collet turn the square section piece into a rod which fits in the 3 jaw chuck. Once you have the rod in the 3J chuck, you can turn the pegs without the need to insert the metal rod. I'm sure others will have ideas to help you - and well done for having a go. welcome to a great and interesting journey as you learn how to turn using this great tool. Des in Oz ------- Re: Help for a newb Posted by: "Mark Sicherman" marksichermanx~xxgmail.com mark_james_1960 Date: Wed Dec 3, 2014 3:46 pm ((PST)) Thanks, I actually have increased my level of success somewhat doing one of the things you suggested and one other that made sense to me. The lathe, as you know, came with some 1/4 x 1/4 cutting tools and I bought one blank one. I milled part of the profile into one end of the blank one, another part into the opposite end of it, and a third part into the back end of one of the stock ones. That cuts quite well, actually, and I'm encouraged again. It would be nice if I could make it out of one piece, though, to speed things up. Are there blanks available premade to make my own or would I have to weld something up? If so, what kind of steel is appropriate for a cutter? Thanks for your help! mark ------- Re: Help for a newb Posted by: kvaughanx~xxacsalaska.net kenvalaska Date: Thu Dec 4, 2014 6:57 am ((PST)) Good luck with trying to keep corian together at small diameters. I have used it to make perches for bird house Christmas ornaments with mixed results. As the diameter gets down to about 3 mm and smaller, the rate of failure due to breakage increases dramatically. At 2mm it is hard to get much success unless using very plain patterns. Those simulating granite have a higher breakage rant than the plain patterns. Longer pieces (shawl pins with length of about 50 mm) down to 3.5 mm work with breakage on about 10% loss. At 3 mm the breakage goes to about 40% and increases rapidly as the work goes smaller. Keep your edge honed sharp (frequently) as corian does dull tools rapidly. HSS works better than carbide in my experience. The breaks, when viewed under magnification are the result of cleaving of the corian along weak points that are a result of developing the patterns for its use as a surface material. The material comes in a normal 12mm thickness that I saw into nominal 6 mm pieces with a fret saw blade, round between centers and then hold in a collet. Corian turns easily and will scrape-cut without problems. If you are using stainless for the lower pin, the corian "bead" top will work well. Epoxy is less brittle than CA glues and may provide a better longer term hold. Ken in Juneau ------- Repair of Atlas MK2 belt cover. [atlas_craftsman] Posted by: holts001x~xxaol.com crholt44 Date: Tue Feb 3, 2015 4:46 am ((PST)) This may be "old news", but in my quest to find an Atlas MK2 10100 model lathe. I ran across one of the problems you can encounter, a cracked or broken belt cover. Why Clausing used plastic, is anybody's guess; it was certainly cheap, but not very "high impact" for a shop environment. I found that Plastic Weld made by Plastruct worked very well to bond the pieces back together. Those of you into model trains or other hobbies that use Plastruct building shapes are no doubt familiar with Plastic Weld. It is formulated for ABS, Styrene, Butyrate, and Acrylic Plastics. I don't know exactly what Clausing used for plastic material, but it doesn't really matter. Plastic Weld has MEK in it, so any solvent type "glue" will no doubt work, including straight MEK. I tried Testors solvent type (glue) and it didn't seem to "meld" the plastic as well. I hope this helps. Charley ------- Re: Just acquired ML 4 [myfordlathes] Posted by: "Kevin" tadpolex~xxbtinternet.com klokenz Date: Fri Feb 13, 2015 2:33 pm ((PST)) On 13/02/2015, 1044kenx~xxtiscali.co.uk [myfordlathes] wrote: > I have just posted pictures of a ML 4 that I have just collected and > intend to restore. > It has a reduction gear for the rack and pinion built into the handle. > The leadscrew half nuts are worn has any body ideas/suggestions on > repairing or replacing these? > I have been looking at suggestions to repair by forming threads using > epoxy and was thinking of Milliput. There are various places on the Web where you can find instructions for making replacements for the half-nuts in Delrin, which is a thermoplastic material. Basically you make two rough half shell, without threads, heat them up and clamp them around the best bit of the leadscrew until cold. Supposed to work well, but I've not tried anything along those lines. But it did get me thinking that there's a rather low melting polymer (a type of Nylon I believe) available from places like Maplin (and no doubt Radiospares at twice the price). This stuff melts in hot water, and might be useful for at least proving the method, and might turn out to be not too shabby even. Here's a link to get started: http://bbs.homeshopmachinist.net/threads/43645-Making-Acetal-lead screw-nuts-the-easy-way Kevin, England ------- Re: Just acquired ML 4 Posted by: "Pip" pipx~xxhvtesla.com philiptuck Date: Sat Feb 14, 2015 7:28 am ((PST)) I tried the Delrin trick of using heat, and was not very impressed with the result, as getting the tempature right was tricky. Too high or too low, gives a poor thread form. On the other hand thread cutting Delrin, or tapping it, is very succesful though. I would make a tap with the leadscrew thread and tap a block of Delrin. My last mill had Delrin for the x-axis leadscrew, and it had no backlash. Regards Phil Tuck www.hvtesla.com ------- [sherline] [Original title was misspelled as "groves"] Cutting grooves in plastic Posted by: mikeydx~xxsuddenlink.net mandjsstuff Date: Sun Mar 1, 2015 6:52 pm ((PST)) I'm working on a model where I need a series of grooves cut in plastic. Each groove will be 1/16 inch wide with 1/16 between them. I'm thinking I can cut them more accurately with a mill than by hand. My idea is to use a mill at high speed, either cutting the slot in one or two passes. Thoughts before I screw it up? ------- Re: Cutting grooves in plastic Posted by: "Charles" catkinsonfoxx~xxgmail.com cafox513 Date: Sun Mar 1, 2015 6:58 pm ((PST)) In plastic -- go slow! Beware heat. Take small bites. ------- Re: Cutting grooves in plastic Posted by: "DJH Yahoo" djhmisx~xxyahoo.com djhmis Date: Sun Mar 1, 2015 7:14 pm ((PST)) There are bits made for plastic... check with MicroMark Don ------- Re: Cutting grooves in plastic Posted by: chieftoolmakerx~xxearthlink.net glicker31 Date: Sun Mar 1, 2015 7:27 pm ((PST)) How many grooves? How deep? Full width of the job/plate? What kind of plastic? Jerry G (Glickstein) ------- Re: Cutting grooves in plastic Posted by: "ED MAISEY" holmes_ca_2000x~xxyahoo.com holmes_ca_2000 Date: Sun Mar 1, 2015 8:11 pm ((PST)) Mike, not too high a speed or you may melt the plastic and get a nasty mess, what is the plastic? Edmund ------- Re: Cutting grooves in plastic Posted by: jowhowhox~xxyahoo.com jowhowho Date: Sun Mar 1, 2015 9:21 pm ((PST)) I'm using a 1/16" straight single flute carbide router bit to cut through-holes in ABS. It works perfectly, and is cheap. MLCS (because they are 1 mile down the street from me) Single Flute Straight #5465 1/16" $6.95 ------- Re: Cutting grooves in plastic Posted by: "Wolgamott M" mnwolgamottx~xxyahoo.com mnwolgamott Date: Mon Mar 2, 2015 3:51 am ((PST)) Of course practice of a piece of scrap first; use an air stream to blow chips away with coolant (water) aspiration if you can do this. Use a plastic cutting bit single lip and slower may be better than faster depending on the type of plastic. M. Wolgamott ------- Re: Cutting grooves in plastic Posted by: "Mikey D" mikeydx~xxsuddenlink.net mandjsstuff Date: Mon Mar 2, 2015 6:01 am ((PST)) Thanks for the replies. It's a model car, made of polystyrene. The car had eight slots to release air. It's the Don Schumacher Wonder Wagon Vega. ------- Re: Cutting grooves in plastic Posted by: "Charles Fox" catkinsonfoxx~xxgmail.com cafox513 Date: Mon Mar 2, 2015 6:23 am ((PST)) We’ve often used label tape to guide a tool like a Zona saw ... with great care. ------- Making HDPE stock [sherline] Posted by: davidryx~xxosorail.com david_rygmyr Date: Tue Feb 16, 2016 11:10 am ((PST)) Thought I'd pass this one along; interesting way to recycle milk jugs and turn them into bar stock for machining. http://makezine.com/2016/02/15/turning-an-hdpe-milk-jug-into-a-mot or-pulley/ Dave Rygmyr NorthWest Short Line (www.nwsl.com) ------- ------------------------------------------------------------------ This is just one of some 80 files about machining and metalworking and useful workshop subjects that can be read at: http://www.janellestudio.com/metal/index.html ------------------------------------------------------------------