For the new metal lathe owner, one of the greatest mysteries to be solved is how to use the thread dial attachment (assuming the lathe has one), along with the half-nuts (also called split nuts) that connect the lathe carriage to the lead screw so that it will move under lathe power. Every user will eventually have to replace, rebuild, or make half-nuts when they become worn. 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 more than 70 additional files on my home page Machining and Metalworking at Home http://www.janellestudio.com/metal/ 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. If you do not have those most recent official instructions, acquire a copy through the manufacturer before operating or using their product. Where the company no longer exists, use the appropriate news or user group to locate an official copy. Be careful -- original instructions may not meet current safety standards. Updated safety information and operating instructions may also be available through a local club, a local professional in the trade, a local business, or an appropriate government agency. In every case, use your common sense before beginning or taking the next step; and do not proceed if you have any questions or doubts about any procedure, or the safety of any procedure. Follow all laws and codes, and employ certified or licenced professionals as required by those laws or codes. Hazardous tasks beyond your competence or expertise should also be contracted to professionals. Let's be really careful out there. (c) Copyright 2003 - 2007 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: Mon, 12 Feb 2001 20:21:49 -0000 From: WThanelx~xxaol.com Subject: Thread Counting Dial Gear M6-64 or M6-64A? I have recently restored (assembled from parts) an Atlas 6 inch 618 lathe and decided to try turning some threads. Upon trying to use the thread counting dial I noticed it will not stay engaged with the leadscrew. When the half nuts are disengaged I can push the dial gear against the leadscrew and tighten down the positioning bolt. The dial will then rotate as the carriage is moved. As soon as I engage the leadscrew the gear disengages and the dial does not turn. I see in the Atlas 618 parts list that two dial gears are listed, the m6-64 and the m6-64A, hmmm. I have assembled this lathe from new and used parts. The leadscrew and gear appear to be in exe condition. I don't think the thread counting dial came with the leadscrew so its possible I have the wrong gear. Only one lead screw number is listed in the Atlas parts list. Has anyone had this problem? What is the difference between the M6-64 and the M6-64A gear? Thanks Bill T. ------------------------ Date: Mon, 12 Feb 2001 15:36:46 -0500 From: Jude Miller Subject: Re: Thread Counting Dial Gear M6-64 or M6-64A? I have a 6" A/C with a 32 tooth dial gear. Some of the 6" Atlas lathes have a 16 tooth dial gear. Perhaps that is the difference? You could call Clausing and ask. The 16 tooth gear saves a few seconds each time you start another pass, but the 32 tooth gear allows you to cut 1/2 threads, e.g. 11 1/2 tpi, a pipe thread. Best, Jude Miller -------------------- Date: Mon, 12 Feb 2001 16:01:00 EST From: BACSTGx~xxaol.com Subject: Re: Thread Counting Dial Gear M6-64 or M6-64A? There are two possibilities here. When you engage the half nuts the dial should not rotate. It should stay where it was when you engaged them. The carrage moves at the same rate as the lead screw is turning so the gear on the dial is just following the grove in the leadscrew. The other possibility if this is not the problem is that when the leadscrew is engaged it is slightly warping the carriage and causing the gear to pull off of the leadscrew. To fix this you need to shim the distance between the halfnut and the carrage. My old one before I sold it had two thin washers to take care of this problem. Hope this helps. Keith ------------------------- Date: Wed, 14 Feb 2001 00:06:29 EST From: catboat15x~xxaol.com Subject: Re: engaging carriage In a message dated 2/13/01, lnicex~xxattglobal.net writes: > Sometimes when I engage it it locks onto the leadscrew > smoothly and sometimes it takes several tries before it engages. What am You are doing nothing wrong. The half nuts will not engage if they are trying to close on top of the thread, when the lead screw turns so the half nuts are on the thread properly they will engage. I usually put light pressure on the lever to engage the half nuts and when they and the lead screw are in "sync" they just drop in. You are correct in not forcing anything here. John Meacham High Desert of California, Palmdale, Littlerock. ------------------------------------- Date: Tue, 13 Feb 2001 23:35:19 -0600 From: "J Tiers" Subject: Re: engaging carriage Perhaps you are not observing the thread dial (if you have one) correctly, or it is out of correct alignment. You should ONLY be able to engage when a line on the dial is RIGHT on the index mark on the dial housing. The further off the mark it will engage, the more wear and consequent slop your nuts and screw have. In some cases it will engage halfway between marks, that is also OK. If the mark is off the index when it goes in, shim the dial where it fits against the carriage, or turn the gear on the dial shaft to bring it back in. If no dial, then it still engages, but you cannot easily see where! Jerry -------------------------------- Date: Wed, 14 Feb 2001 00:54:40 -0600 From: Jon Elson Subject: Re: engaging carriage You probably have wear on the half-nuts. Also, there is a 'bracket' that holds the half-nuts in proper position, and it can get loose. Check to make sure the entire half-nut mechanism is clean, well lubricated, and that the half-nut pieces themselves are held securely in the little vertical tracks that guide them. Keep the leadscrew clean and well lubed, too. I think that using the threading dial to select the proper moment to attempt engagement is a big help. If you are trying to do it by feel, you may be causing excessive wear this way. Jon --------------------------- Date: Mon, 12 Feb 2001 22:37:11 -0000 From: WThanelx~xxaol.com Subject: Thread Counting Dial Gear M6-64 or M6-64A Solved ! My original question has been solved. Although I still don't know the difference between a M6-64 and a M6-64A I guess I really don't need to. Thanks to some fellow memebers I now know thread counting dial is working correctly. Having never used one before I was unfamiliar with its operation principals. Thanks to all that replied for the info. Bill T. -------------------------- From: To: Sent: Tuesday, February 13, 2001 10:00 PM Subject: [atlas_craftsman] engaging carriage > Got a question for you. I have a 10" Atlas that seems to have very > little wear on it and except for an annoying problem with engaging the > carriage seems to performs well. The problem I have (at least I think I > have) is an erratic engagement of the half nut to start the carriage > (horiz) to move. Sometimes when I engage it it locks onto the leadscrew > smoothly and sometimes it takes several tries before it engages. What am > I doing wrong here? I don't want to force it and break something. Thanks > for any suggestions. Iceman I saw your post on leadscrew engagement. Firts make sure thread dial is turning freely and the little gear is engaging the leadscrew consistently. Sometimes the gear may not be swung far enough in to totally engage the leadscrew consistently. Take a peek at the half-nuts in the carriage. They may be worn and need replacement. Make sure no chips or dirt have accumulated to slow the action of the half nut lever. Flush out with some sort of solvent and put in clean lube. Look at the leadscrew itself for worn down threads. You may need a replacement. If wear or dirt or chips are not the problem, you may be closing the half-nut lever too soon or too late. The little index marks on thread dial and dial body are approximate. As the manual says, different marks for different threads, odd or even number. Make sure the right marks are used for the thread you want to cut. You have to get a "feel" for when to close the lever and how fast to close it. Leadscrew may turn faster or slower depending on thread being cut. You have to go faster or slower in closing the half-nut lever. Sometimes you have to close the half-nut lever just before indicator marks meet. I hope this helps. J. Sprott Kansas City, MO --------------------------- Date: Wed, 14 Feb 2001 09:01:25 -0700 From: "Maxwell Sandford" Subject: Re: engaging carriage > The problem I have (at least I think I > >have) is an erratic engagement of the half nut to start the carriage > >(horiz) to move. Sometimes when I engage it it locks onto the leadscrew > >smoothly and sometimes it takes several tries before it engages. Now that this thread is going well, has anybody started to design a synchronizer ring for Atlas lathes? Like any transmission, you can only powershift when the nut thread is lined up with the leadscrew. My 6" behaves exactly this way too, owing of course to the simple design of the half-nut engaging mechanism. It engages smoothly when the teeth are in position with the leadscrew, so there is no substitute for operator training. ------------------------------- Date: Wed, 14 Feb 2001 12:14:30 -0500 From: Jude Miller Subject: Re: engaging carriage > I guess I need to be trained. Everyone answered this question as if he was > threading. What if he was not threading but only turning and did not have > the thread dial engaged? Jerry Halcomb You can still only engage the half nuts when the threading dial is at one of the marks or half way between. Just use the carriage handwheel to move the carriage until the threading dial lines up with the mark. Otherwise, use very gentle pressure on the half nut lever while you move the carriage slightly. You should be able to feel when the half nut will engage. Best, Jude Miller ----------------------- Date: Wed, 14 Feb 2001 09:24:13 -0800 From: "Bob May" Subject: Re: engaging carriage When you engage a halfnut, the square threading keeps it up until you have an alignment. Push gently and all of a sudden, it will drop in. If you engage the thread dial, you will quickly see which positions that it will engage in. I, probably like a lot of us, keep the thread dial engaged and watch it for when it indicates an alignment and that's where I push down firmly. Any other place just frustrates you as you have already found out. Pushing and releasing can also mean that you miss the thread for several threads as you just jump over the alignment point! Bob May My new web space address is http://webu.wigloo.com/bobmay/ or http://nav.to/bobmay and my new email address is bobmayx~xxnethere.com -------------------------- Date: Wed, 14 Feb 2001 16:15:20 -0600 From: Jon Elson Subject: Re: engaging carriage Adam wrote: > At 10:52 AM 02/14/2001 -0600, you wrote: > >Everyone answered this question as if he was > >threading. What if he was not threading but only turning and did not have > >the thread dial engaged? Jerry > Basically the same thing, except you don't need to pay attention > to the marks on the thread dial. One of the first replies I saw mentioned > closing the half nuts with a certain kind of 'touch', not forcing but more > like easing it in. The half nuts will still only engage when the threads > are lined up with the lead screw, that holds no matter what operation you > are running... Well, after there is some wear in the nuts, rounding off the corners, etc. you CAN engage the nuts on the side of the thread. In other words, you can get the nut only partially engaged over the leadscrew. When threading, this causes a big mess, as the tool will not be in the right alignment to the thread you are cutting. I suspect this partial alignment also increases wear on the nuts. So, I am very careful to use the threading dial and a very light touch to get the nuts engaged. Jon ----------------------------- Date: Sat, 25 May 2002 21:41:55 -0500 From: "jerdal" Subject: Re: split nut problem > Hello,My 109 split nut will not stay engaged when cutting without > having to hold it down.After examining the problem I discovered part > of the bottom half was broken off.Is there any wat this can be > repaired.Otherwise the lathe operates perfectly.Any Ideas? Bill There is a detent that is supposed to hold it in position. Evidently this is the part broken off. You could probably braze on a part to replace it, and drill for the detent parts. Finding new ones or replacement is an Ebay issue, as NOS parts are probably not happening anymore. Or, one of the folks here who has a machine to part out may have something. One of the articles on the machine in HSM / MW had an "always engaged" nut description. This might not be too bad, since the leadscrew is used for ALL carriage movement on these machines. Jerry --------------------------------------------- Date: Sun, 26 May 2002 03:05:25 -0000 From: "bill_collins14" Subject: Re: split nut problem Jerry, The detent is fine. It is part of the bottom half of the nut part itself that has a piece broke off. I took the carriage off and re- examined the piece and found that part of the bottom half of the threaded section was missing. If I can't find a replacement piece then maybe I can fabricate a new piece for it. I had to make one similar for an old Shepard lathe I used to own and it was much older than the 109. As for the detent it is fine, in fact when I first got the lathe I had to replace the ball bearing that presses against the indent on the split nut that's supposed to hold it in position. I'm sure I will figure something out. Thanks Bill -------------------------------- Date: Sat, 25 May 2002 22:14:00 -0500 From: "Mario L Vitale" Subject: Re: split nut problem Bill, There was an article about a year ago in Home Shop Machinist / Projects in Metal mag (and it was discussed by this group) on how to repair the half nut. If you are interested and can't find the article, let me know and I'll see if I can dig it out for you. It may take me a day or two. My filing system is great...it's my retrieval system that stinks!!!! Mario ------------------------------------------ Date: Sat, 25 May 2002 22:43:54 -0500 From: "Mario L Vitale" Subject: Re: Re: split nut problem Bill, It looks like we are on the same schedule! I found the article (Machinist's Workshop [used to be Projects in Metal] magazine, Dec 2001/Jan 2002 Vol 14 #6 page 27.) It is discussing repairing the half nuts on a SB 10K lathe but the process would work for any lathe. The basic approach is to build a fixture that holds the two nut halves in the same relative position that they are held in the apron, build up the worn surfaces with braze material, and then tap the threads to match the lead screw thread. If you can't find the magazine let me know and I can try to scan the article for you. Mario -------------------------------------------- Date: Sun, 26 May 2002 03:57:26 -0000 From: "bill_collins14" Subject: Re: split nut problem Mario, with the AA 109 both halves of the split nut are cast onto the same piece that engages on the lead screw. I may have to go with something like on the Gingery lathe. Or when I fixed the one on the old Shepard lathe I cut a nut in half that matched the lead screw and welded them onto a piece of CRS plate then used a hacksaw to remove the waste and finished the shaping on a bench grinder then drilled the holes needed to mount it to the apron. Gotta put my old brain to use. Thanks a bunch. Bill ---------------------------------------------- Date: Fri, 08 Nov 2002 09:04:14 -0800 From: Rick Kruger Subject: Restoring worn half nuts with a bronze sleeve Not wanting to wait for Brett to figure out how to get into Yahoo groups, I've uploaded his description and photos of how he restored badly worn SB9 Model A half nuts using a bronze sleeve. While this was done on a SB lathe, clearly it has application to any lathe. Its a mystery how these nuts were worn out so completely, but there was almost nothing left of the threads. Since it is a Model A, power feed of carriage and crossfeed were thru the leadscrew keyway, not the half nuts. Half nuts were only needed for threading. The lathe was in a high school shop for a long time. A short description file and two photos have been uploaded to the FILES area. http://groups.yahoo.com/group/atlas_craftsman/files/RestoredHalfNuts/ Brett will not see discussion posted to the Atlas group, but I can relay. If you want to ask Brett questions offline, please email him at: efficientvelox~xxaol.com Rick K. Portland, OR ------------------------------------ Date: Thu, 2 Jan 2003 21:42:21 EST From: LouD31M066x~xxaol.com Subject: Re: 618 Atlas metal lathe [HALF-NUT PROBLEM] Check with Clausing Atlas...as of last year they were $15.72 for pair of half nuts new. Complete assembly $49.42 ...now there you might want to shop a little. I have quoted from 05/14/01 price list for my 101.21400 six inch lathe...I assume the parts are the same and price has not gone up too much since.... sometimes not the case so check first. Are you sure half nuts are unusable? Reason I ask is my well worn lathe had lead screw coated with gummed up oil and crud and half nuts were full of shavings and gummed up oil...after lead screw was cleaned up and shavings picked out of half nuts there was nothing wrong with either! Anytime you avoid buying things you don't need you have more money left to spend on the things you do need...don't even think about asking how I learned this! Louis ------------------------------------------------ Date: Thu, 2 Jan 2003 22:13:21 EST From: LouD31M066x~xxaol.com Subject: Re: 618 Atlas metal lathe Have read your message again. I went off half cocked. Let's start over... Is lead screw coated with a varnish that fills thread? I used power wire brush to remove...if had to do it over I would use a bronze or brass instead of steel wire wheel. Are all the parts present and accounted for? Is wear or breakage obvious? Do you have owners manual or can you access from group web site? The parts involved are sacrificial items made of easily broken material that will give way in case something has to give. Except for handle they are reasonable and available (as of last year) M6 13a guide $4.33 M6 12A half nuts(pair) $15.76 M6 38 cam $2.79 M6 29 lever is a pricy $38.23 but A) not likely the problem and B) clever native craftsman can make substitute. If new parts are available reasonably why bother with used in this application? At least that's how I see it. (2nd time anyway) Final thought..is spring and ball assembly present and free of gunk and crud? It is not clear from drawing where they fit but something has to provide positive position of in or out on half nut. Do not have carriage available just now...out being ground. Louis -------------------------------- Date: Fri, 3 Jan 2003 03:11:15 -0500 From: "mertbaker" Subject: Re: 618 Atlas metal lathe You can get the "Loctite Thread Restorer" kit at an automotive store. Follow the directions exactly. Mert MertBakerx~xxprodigy.net ------------------------------------ Date: Fri, 03 Jan 2003 18:03:34 -0000 From: "speedphoto300 " Subject: Re: 618 Atlas metal lathe Dennis If you do buy the half nuts, check first to see if your old ones are .5 or .75 inches wide, the ones available from Clausing are the more recent wider ones. If yours are the narrow ones you either need to get the M6-13A guide or widen the slot in your old one. Joe -------------------------------------- Date: Mon, 10 Feb 2003 05:10:27 -0000 From: "don_kinzer " Subject: Re: Cutting a gear on the shaper [A TALK ABOUT THE THREAD DIAL HERE] --- In Metal_Shapersx~xxyahoogroups.com, jrw wrote: > Don: The part I do not understand is the comment about > needing five gears for the threading dial. The way that the thread cutting gearing works out on this lathe (which, again, has a metric leadscrew) a 16T thread dial gear will work for .3, .4, .5, .6, .75, .8, 1.0, 1.2, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0 and 12.0 mm pitch threads. For all but the 8.0mm pitch, the halfnut can be engaged on any of 8 marks on the dial. For the 8mm pitch, only the 4 numbered marks may be used. For other thread pitches, you need different thread dial gears. An 18T gear covers some of the same pitches (although the halfnut can only be engaged on the "1" mark or, in some cases, the "1" and "3") but also adds .45, .90, 4.5, and 9.0mm pitch. A 20T gear adds 1.25, 2.5, 5.0 and 10mm pitch and the halfnut can be engaged on any of 4 numbered marks. A 21T gear adds .35, .7, 1.4, 1.75, 3.5 and 7.0mm pitch but the halfnut may only be engaged on the "1" mark. Lastly, a 22T gear adds 1.1, 5.5 and 11mm pitch, halfnut to be engaged on "1" or "3". The manual that I have for the lathe, unfortunately, only covers the Imperial (inch) leadscrew. I had to work all of this out using a spreadsheet. The advantage of this process is that I now understand how the thread dial works. I could probably get by without the 18T and 22T gears but while I have everything set up I might as well make them. Don Kinzer Portland, OR -------------------------------- Date: Wed, 19 Feb 2003 12:00:30 -0500 From: "John Glowacki" Subject: Mitre Gear/Half Nut After falling on a small patch of ice in my Wisconsin driveway 12/20/02, I was finally able to hobble to my shop last night. I just sat on my stool and gazed at my various un-finished projects. It was great just to be there. I've had it with taking life for granted! I just called Clausing for parts prices for my A/C 101.07403. The mitre gear (P/N 10F-82A) that slides over the lead screw and drives the cross feed power is almost a hundred bucks!! Mine is missing the key protrusion that interlocks with the slot in the lead screw. For a hundred bucks, I think I can tinker for a while and try and fix it. I will bore out the gear and press in a brass sleeve with an internal key affixed to the inside. Or I might just try to affix an internal key to the inside of the gear bore. Also I priced the half nut P/N 10F-12 at about $28. Someone was asking about half nuts for a six inch Craftsman. Is that the same part number? Well, I'll be back in my shop tonight. John Glowacki ---------------------------------- Date: Wed, 19 Feb 2003 12:06:21 EST From: LouD31M066x~xxaol.com Subject: Re: Mitre Gear/Half Nut Glad to hear you are up and at it again....somewhat anyway. 6 inch half nut part number is M6-12A (pair) halfnuts $15.76 May 2001 price list. Difference between ordering part and a project is cost. Some parts are too inexpensive to try to make and others are too complex and difficult. Where the part is either unobtainable or easier to make than to pay for you have a project. Sometimes projects annoy and divert us from a primary task sometimes they offer variety and the opportunity to enhance our skills. The question is fix, find, adapt or improvise? Have fun! Louis -------------------------------------- Date: Wed, 19 Feb 2003 12:33:26 -0600 From: Jon Elson Subject: Re: Mitre Gear/Half Nut John Glowacki wrote: >I just called Clausing for parts prices for my A/C >101.07403. The mitre gear (P/N 10F-82A) that slides over >the lead screw and drives the cross feed power is almost a >hundred bucks!! Mine is missing the key protrusion that I'd go for the brass sleeve, it will be a lot stronger than any key you might be able to cobble into the gear. Remember, the original cast-inkey sheared off due to the force on it. The sleeve will support the key much better. >Also I priced the half nut P/N 10F-12 at about $28. > Someone was asking about half nuts for a six inch >Craftsman. Is that the same part number? No, the 6" has a 16-pitch leadscrew of smaller diameter. So, the half nuts are not the same. In fact, very little is compatible between the 6" and other lathes. ------------------------------- Date: Wed, 19 Feb 2003 13:52:42 -0500 From: "John Glowacki" Subject: Re: Mitre Gear/Half Nut If I do bore out the mitre gear and fabricate a brass bushing with an internal key protrusion: 1. The wall thickness would be about 1/16" on both the gear and the bushing. With the gear being about 1" in diameter and 1 1/2 or 2" long, can I hold this in a chuck (3 or four jaw) for machining? I'm thinking that the chuck jaws might crush the thin wall. 2. What diameter differential would make a good press fit? 0.002"? I could heat the gear before pressing in the bushing. Thanks for the help. John Glowacki ------------------------------- Date: Wed, 19 Feb 2003 14:26:03 -0500 From: Stan Stocker Subject: Re: Mitre Gear/Half Nut Hi John, If the bevel gear is one of the Zamac (cast stuff) ones, you might do better to go with a sliding fit and secure the sleeve with some thinned epoxy or one of the high strength bearing retaining compounds. Zamac isn't very good in tension. Cheers, Stan ------------------- Date: Wed, 19 Feb 2003 15:46:22 -0500 From: "John Glowacki" Subject: Re: Mitre Gear/Half Nut Stan, I don't think my gear is zamak. It sticks to a magnet. Zamak wouldn't stick to a magnet, would it? John Glowacki ----------------------- Date: Wed, 19 Feb 2003 17:24:21 EST From: LouD31M066x~xxaol.com Subject: Re: Mitre Gear/Half Nut No...I think more due to very small scale of interest/demand. The supplying of parts for any obsolete product is more an act of generosity on part of manufacturer than a source of profit. It takes a certain minimum amount of resources to provide parts and service whether sales are high or low and the cost must be reflected in price. In our situation we should be glad that our old machines still have many parts available new even at costs that seem high. Otherwise we would have to junk our machines for want of the proverbial horse shoe nail. It was a different story when our machines were in current production. Then parts and service were profit centers contributing to overall success of business...not so now. Louis --------------------------- Date: Wed, 19 Feb 2003 17:37:34 EST From: LouD31M066x~xxaol.com Subject: Re: Mitre Gear/Half Nut Magnet identifies as iron or steel and rules out zamac. Be very sure you are not dealing with an insert of some sort. Atlas was very partial to zamac parts as they were cheap, serviceable and provided a wearing or weak safety link in their design. Louis ------------------------- Date: Wed, 19 Feb 2003 17:40:15 -0500 From: "John Glowacki" Subject: Re: Mitre Gear/Half Nut Yep, I'm sure a magnet sticks to the gear teeth and the shank. It's not zamac. John Glowacki ------------------------ Date: Wed, 19 Feb 2003 17:57:32 -0500 From: Stan Stocker Subject: Re: Mitre Gear/Half Nut Hi John; Sounds like your part isn't Zamac! Makes life nicer indeed. 2 thou sounds pretty good on a one inch diameter for the fit, given the amount of surface area even a thou would likely do fine. On small parts like this I often heat the outer part over a light bulb and put the inner piece in the deep freezer. Line it all up, don't dawdle, and tap the part home quickly. Any chance you could just broach a keyway and fit a key in the existing piece rather than go through the effort of boring out and fitting a liner that still required a key to be secured in some way? Good luck with it, Stan ---------------------- Date: Wed, 19 Feb 2003 17:55:52 EST From: LouD31M066x~xxaol.com Subject: Re: Mitre Gear/Half Nut ---Louis' msg a few minutes earlier--- >> If gear is zamac (I suspect it is) it might not be up to much in way of heat or pressure so I would go with an epoxy glue and a slide on fit. You have the dollar figure of the part to bear in mind! Holding to machine might also be a place where an epoxy glue and very gentle cuts could work where other more vigorous measures would put you in deep doo doo. $0.00000002 worth. Louis << Please forgive my assumption of zamac. If gear is steel I am wondering what did it wear on to wear out internal key or keyway? If gear is steel it will likely machine or press or heat okay. If lack of a way to hold it is a problem epoxy to a flat surface you can fasten to face plate (indicated center) and make fine cuts might be one way out. My humble opinion and sometimes I have much to be humble about. Final thought...goal is to have renewed internal key and bore concentric to center of gear surface, solidly bonded together to transfer motion from leadscrew to crossfeed. Should be doable with due attention to making things concentric and close fit. Thought occurs that if outer surface is machined (and concentric to gear) you could turn and bore a piece of barstock to make a holding fixture using epoxy to grip gearshaft while boring it out then using source of heat to weaken epoxy so as to remove gearshaft from fixture. That way no chuck jaw distortion of gearshaft being held....opinion worth what you pay for it. Louis ------------------------------ Date: Wed, 19 Feb 2003 20:12:05 -0600 From: "John Glowacki" Subject: Re: Mitre Gear/Half Nut You know Louis, I'm not so sure my father didn't bore the key out of this gear. The other mating gear was missing, along with the mounting stud. I don't ever remember the power cross feed working on this lathe. And I first started playing with this lathe when I was maybe ten years old, some thirty years ago. I can't for the life of me think of a reason why dad would have bored out this key. The hole looks bored out. This could be from a lifetime of spinning on the lead screw. John Glowacki ----------------------- Date: Wed, 19 Feb 2003 20:23:34 -0600 From: "John Glowacki" Subject: Re: Mitre Gear/Half Nut > turn and bore a piece of barstock to make a holding fixture using epoxy to > grip gearshaft while boring it out then using source of heat to weakenepoxy > so as to remove gearshaft from fixture. That way no chuck jaw distortionof > gearshaft being held....opinion worth what you pay for it. Louis Now you're getting the gears turning, so to speak. This might be my answer. Or even a custom collet to hold it in a chuck? John Glowacki ---------------------- Date: Wed, 19 Feb 2003 20:17:33 -0600 From: "John Glowacki" Subject: Re: Mitre Gear/Half Nut Two things Stan, 1. I'm a bit puzzled as to how I could affix a key to the inside of the gear itself. If I make a brass sleeve, I can braze or silver solder it in. 2. The inner bore of the gear is a bit open. There might be too much play between the inner bore and the lead screw. How much play should there be? John Glowacki ------------------------ Date: Wed, 19 Feb 2003 22:34:18 -0500 From: Stan Stocker Subject: Re: Mitre Gear/Half Nut Hi John; I'm far more familiar with South Bend, the Atlas I'm wrapping up is the first I've worked on. On South Bend lathes, the key in the worm has ears on the end, and is quite thin in the section that goes through the worm. The ears keep the key from sliding out of the worm when the leadscrew is in place. The key just about falls out when the lead screw is removed, only a light tap with a brass drift is required to free it. On the Atlas, the leadscrew runs through one of the bevel gears rather than through a worm as we all know. What I don't know is if there is enough meat at each end, or enough room for a key with ears and just a shallow slot through the gear body. Unfortunately, I have no idea what the fit is on new Atlas gears and leadscrews. I was thinking that if you had room to bush, you might have enough room to go with the key with ears approach and save some time, or to secure a key into the existing gear using lower temp silver bearing solder which flows at around 475F unlike the higher temps required for true silver or brass brazing. I don't think I'd choose to take a steel gear that is probably heat treated up to true brazing temps, although I've done it often enough on cast iron gears to replace teeth. Sorry not to have been more complete in explaining what I was thinking of, I'm just so used to SB that I often forget that Atlas did things differently in some areas. Cheers, Stan -------------------------- Date: Wed, 19 Feb 2003 22:46:38 EST From: LouD31M066x~xxaol.com Subject: Re: Mitre Gear/Half Nut If you are missing more ie. both gear and stud I would follow ebay and ask group if anyone has the parts lying in their bone pile. The repair you are considering is doable but why bother if you still need stud 10F-17 and gear 10F-83. I do not think these are wear items so used should be okay. Another angle is to see if Boston Gear(or their competition) has gears (mitre and spur ) that you can join to make 10F-83. You might have to make the whole setup if you cannot find match for 10F-82 mitre gear. Looking at prices I see you have strong incentive to "roll your own" in this situation including mounting stud 10F-17. I suppose you could even make your gears from scratch, but, I think that might be a stretch. Louis ----------------------------- Date: Wed, 19 Feb 2003 22:51:01 EST From: LouD31M066x~xxaol.com Subject: Re: Mitre Gear/Half Nut My two cents on fit...this is all "Government Work" so any thing that works is okay. If it don't work the first time it will the next. Louis ----------------------------- Date: Thu, 20 Feb 2003 08:12:57 -0500 From: "John Glowacki" Subject: Re: Mitre Gear/Half Nut A while back, I bit the bullet and bought new from clausing the stud and gear 10F-83. The stud didn't cost much and the gear was a bit more, perhaps $50++. I bought these parts thinking I would be done. When I was putting everything together, I couldn't figure out how the power went from the lead screw to the gear. You folks helped me out on that. Then I realized my built in key wasn't there. John Glowacki ---------------------------- Date: Wed, 05 Mar 2003 08:46:58 -0000 From: "Robert Weersing" Subject: Re: Help!! parts needed for a 9" --- In atlas_craftsmanx~xxyahoogroups.com, "CRAIG THOMPSON" wrote: > I need a set of half nuts for a 9" atlas anyone got any or know > where to get them? otherwise i need to buck up and buy an acme > tap for $58 and make them myself. Please help me!!! Thanks, Craig Hello Craig Forget calling Clausing, they only carry the 10F half nuts. The only place to find them is on Ebay. you can use the half nuts from a 9" or early 10" Atlas lathe up to a "D" model with the 5/8 lead screw. The Part number is 9-12 Lots of luck Bob ------------------------ Date: Wed, 5 Mar 2003 00:26:48 EST From: n8as1x~xxaol.com Subject: Re: Re: Help!! parts needed for a 9" snocat_trfx~xxhotmail.com writes: > I just might be making them, though i need to buy a 5/8-8 acme tap single point threading a 5/8 x8 is only more difficult than internal v threading in the necessity of grinding the tool bit..........grind it undersize,set the compound parallel to centerline,cut the thrd w/ x/slideto FULL DEPTH ,take .001to .002 cuts w/compound shaving& cleaning up sides of thrd till u get the fit...........................then there is lubeing the l/screw & closing the releived nut on l/screw w/ JB weld............oooor replacing lead screw w/ piece of 3/4x8 acme rod................ best wishes docn8as -------------------------- Date: Thu, 17 Apr 2003 13:29:58 -0500 (CDT) From: dswrx~xxwebtv.net Subject: Re: Proper procedure for engaging half-nuts on 6" Bruno, The half-nuts can be engaged/disengaged with the lathe in operation or stopped. When you close them, you can feel when they match the thread on the leadscrew. In threading operations, it is almost mandatory that you engage them while the leadscrew is turning. Leo (pearland, tx) ------------------------------- Date: Thu, 17 Apr 2003 12:43:11 -0700 From: John Weight Subject: Re: Proper procedure for engaging half-nuts on 6" Hello Bruno, Yes it is perfectly safe to engage the half nuts with the lathe running. In fact the thread on the leadscrew is an Acme thread with sloping sides.....when you watch the threading dial marks coming up to the reference line you can start to engage the half nuts "very slightly" before the two marks line up, then you can feel the nuts close on the leadscrew, (which helps to ensure that the half nuts are fully engaged) If I can help you any more please do not hesitate to E-mail me.....I taught Machinist apprentices for quite a few years and always enjoyed it Going back to the threading, you will obviously be turning the component at a slow speed, and with practice you will be able to come up to a shoulder pretty closely before disengaging. Wher are located ???? What are your interests??? regards John W San Francisco ------------------------------------- Date: Thu, 17 Apr 2003 16:05:02 -0400 From: "Rigrac" Subject: Re: Proper procedure for engaging half-nuts on 6" Bruno: Split nut can and should be engaged with machine and lead screw both running. It would be extremely difficult to cut a thread by having to stop machine to engage split nut on every pass. All parts of screw and nut are designed to be engaged when running. Ron -------------------------------------- Date: Thu, 17 Apr 2003 23:06:11 -0500 From: "jerdal" Subject: Re: Proper procedure for engaging half-nuts on 6" I will disagree............ sort of...................with the other folks. It WILL damage the halfnuts to engage a lot when you are not in synch with the leadscrew. You may run the risk of cutting a new thread partway into a shoulder of the existing thread. Can't happen, you say? I've seen it, the P.O. of my lathe did that, I had to replace the halfnuts. You need the threading dial to do it right. It shows the exact moment to engage for your thread pitch. Since you don't mention a dial, I will assume you do not have it. In that case, you have to leave the halfnuts engaged and reverse the leadscrew to be sure to stay in synch with the thread you are cutting. Same as with metric using conversion gears. If you DO have the dial, you are always safe to engage on the same dial mark. Depending on the dial marks, the procedure varies. I will assume you have 4 marks, in which case you engage on any mark for even threads, on numbers for odd, on same mark for half threads (like 7 1/2 tpi or whatever.). Jerrold --------------------------------- Date: Fri, 18 Apr 2003 00:17:59 -0400 From: "Rigrac" Subject: Re: Proper procedure for engaging half-nuts on 6" Jerrold: Strongly disagree. A properly prepared split nut that has a good sized relief at split and has leading thread properly relieved which is to grind away the sharp first thread until thread has a bit of width to it will NOT pick up half way down thread. When engaging split nut you must put gentle pressure down on engaging lever until nut "lines" up with screw and then engagement will be smooth. The only time we leave the split nut engaged and reverse the spindle is when we are either cutting a double start thread or when cutting a metric thread on an imperial machine. Ron ----------------------------- Date: Thu, 17 Apr 2003 23:41:25 -0500 From: "jerdal" Subject: Re: Proper procedure for engaging half-nuts on 6" Sorry you don't agree, it is still true. The machines you are used to must be good industrial types, well maintained. These little Atlas etc machines are not made as well, and you absolutely CAN screw them up. As I said, it is no good saying it can't happen as I have seen the results. Note also that I said "if you have no dial", which is true. I don't see how you can easily pick up a finer thread without a dial and without using the equivalent, like chalk marks etc. That I didn't want to go into. The skill required is not shown by the question being asked in the first place by the poster, who is presumably just starting out with his machine. You know that one can't just close the halfnuts anywhere and pick up any old thread of any pitch. And, don't forget a lot of these little machines are bought when already nicely worn by a P.O. who wasn't as skilled as you, So they are already worn, with who knows what pattern of wear, chips, etc on the nuts.. When the P.O. got done with it, do you really think the nuts still have the proper form, lead-in etc? Mine did not, it was worn with two threads, one deeper than the other. The dial showed the original one. I don't know what the guy did, but he messd it up. If he could, others can. Asking a new user to figure out all that is silly. Best to just do it by the book and get cute about it later when the skill level is higher. As you are aware, if you have a dial, as you should to do any serious threading with reasonable ease, you need not worry, as the proper moment is always shown by the dial if it is set up right. Jerrold BTW, some nuts engage straight, sliding into mesh, others close on a somewhat circular path around a pivot. The ones which slide closed mesh all at once, and the leading thread has less influence. Ones that pivot closed have more influence of the first thread, as it is the first to engage. Then the leading thread form is more important. Some S-B pivot closed, most or all AA/109 types pivot closed, Logan slides closed. I think most if not all Atlas slide closed in a straight path. The Logan I have will indeed close partway and stop if you miss the proper moment on the dial. That probably depends on the looseness and wear of nuts and screw and nut-cage slideways. Threadform on this set of nuts and the screw is still good, I replaced the bad ones. So it is possible. ------------------------------------------ Date: Fri, 18 Apr 2003 05:24:18 -0000 From: "azbruno" Subject: Re: Proper procedure for engaging half-nuts on 6" Well, it appears the answer was not as simple as I thought when I posed the question. I do have a threading dial, and will figure out how that works. But the question was posed independent of threading; I was thinking about using the leadscrew for simply running the carriage across. My thought was that depending on how hard or quickly the engagement lever is moved and where the half-nut threads align to the leadscrew, there might be potential for stripping the half-nut threads. I'll reread this exchange again in the morning. -Bruno ------------------------------- Date: Fri, 18 Apr 2003 09:33:09 -0500 From: "jerdal" Subject: Re: Re: Proper procedure for engaging half-nuts on 6" > there might be potential for stripping the half-nut threads. Stripping is unlikely. Wear is certainly possible. Your 6" has a much finer thread on the leadscrew than larger machines, which may have an 8tpi or 6 tpi or even coarser. So there is less material in each thread and wear occurs faster. Obviously there are certain points where the nuts will close, and others where it will not. Attempting to close where it will not only wears the tops of the threads in nuts and screw as the screw turns inside the nut until alignment is reached. The best policy is to watch the thread dial and close when a mark comes past, simply because then there is no wear on the side or top of the threads as you close. But you CAN use the technique Rigrac suggests if you are careful. That is for feeds, not for threading (when you have to be in synch with the partly cut thread). Dial is best for threading, though there are some other approaches to correct synch. I don't use my leadscrew for feeds unless I have to, as it does wear and eventually reduce the accuracy of the screw. I have seen leadscrews worn down to where the threads were rounded and thin, usually right near the headstock. Larger machines have a separate feed rod, or drive the feed from a keyway in the leadscrew. Mine has only crossfeed (facing feed) off the keyway, not turning feed. If you have a handwheel it is good to use that for most movement, using the leadscrew for what it is best at, threading and fine feeds. Jerrold -------------------------------- Date: Fri, 18 Apr 2003 16:33:55 -0400 From: "John Glowacki" Subject: Re: Proper procedure for engaging half-nuts on 6" My 12x36 101.07403 was used by my father for thirty some years in his small machine shop. I learned to use this lathe before I was ten. The half nuts on this lathe were very rarely used for thread cutting. They were used all the time to engage the carriage powerfeed when turning or boring. The thread dial was normally in the up position, meaning disengaged and not turning. To my knowledge, the half nuts have never been replaced. There is considerable wear, but they still work and there is no extra set of threads worn into them. The thread dial is only needed to time the engagement of the half nuts to keep a thread cut in sync. Otherwise, drop the half nut lever at any point to start the powerfeed. John Glowacki --------------------------------- Date: Fri, 18 Apr 2003 21:50:56 EDT From: catboat15x~xxaol.com Subject: Re: Digest Number 1444 If you don't just mash down on the engagement lever you can feel when the proper point is reached. Put a small amount of pressure on the lever and when the half nuts are in the proper relation to the lead screw the nuts will drop in on the threads. John in the high desert of California 12 inch Atlas Mini Mill Rusty file --------------------------------------------- NOTE TO FILE: Spirited and informative, but enough for now. --------------------------------------------- Date: Sat, 19 Apr 2003 03:03:34 -0400 From: Stan Stocker Subject: SB clutch VS halfnuts WAS: Re: Re: OBJECT OF A THREAD DAIL You use the clutch for fine feed. There is a reduction ratio built in due to the worm and wheel in the apron. On my SB13, it's 4:1, so if the gearbox is set for 224 TPI, and the clutch is used rather than the halfnuts, the advance is just proud of 1 thou (0.001116 for you sticklers for detail!) per spindle revolution. The threading chart probably specifies either fine feed rate or the ratio to apply to figure the feed rate. To find the feed rate based on ratio, take the inverse of the gearbox or change gear TPI (1/TPI), and divide by the ratio (4 in my case, different on some other models.) In this case, 1/224 = 0.004464. 0.004464/4 = 0.001116 inch of carriage advance per revolution of the spindle. You could also look at this as 896 TPI, so if you prefer, multiply the TPI by the ratio, then take the inverse. 1/(224*4) gives the same result. This also indicates why you need some tip radius on your cutting tool. If you had a knife sharp 60 degree point on the cutter, and the apron and rack were perfect with no lost motion, you could, in theory, cut a 896 TPI thread this way. In reality, you just get a rough surface (a wobbly torn 896 TPI thread) if you don't put a bit of radius on the tip, but it's a fun thing to think about :-) Model C SB lathes don't have a clutch, power feed is via the half nuts just like the Atlas, so you set up the gear train for the feed rate. Cheers, Stan ----------------------------- Date: Sat, 19 Apr 2003 17:49:53 EDT From: anthrhodesx~xxaol.com Subject: Power Feed (Was Re: OBJECT OF A THREAD DIAL) In a message dated Sat, 19 Apr 2003 05:33:02 -0000, Ken writes: << Interesting exchange concerning halfnut engagement; one question, sorta off the subject, but sounds like someone here probably would know, should you use the halfnuts on a SB or the clutch if you aren't threading? >> Stan pretty much covered it but, so you'll understand the mechanism: The change gears and or gearbox drive the leadscrew at whatever ratio has been set up. If you engage the half nuts the carriage will be driven at that ratio times the pitch of the leadscrew. So if your gear train/gearbox are set for a 1:1 ratio and you have a .125" pitch leadscrew (8 TPI) the carriage will traverse at .125" per revolution of the main spindle. If you set up a 1:2 ratio (Spindle turns once, leadscrew turns half revolution), with the same .125" pitch leadscrew the carriage will traverse .0625" per revolution of the main spindle (since the leadscrew has only made a half revolution the carriage will only traverse half the .125" pitch of the leadscrew). Lets leave the half nuts open but engage the 1:1 gearing to the leadscrew. The leadscrew will still turn at the same rate as the spindle but the carriage will not traverse under power as there is no engagement between the spindle and the carriage. However, besides the half nuts, there is a gear of some sort mounted concentric to the ledscrew and with a key that engages the keyway running the entire length of the leadscrew. Whenever the leadscrew is being driven by the change gears/gearbox this concentric gear is being driven through its key, even if the half nuts are disengaged. On an Atlas this concentric gear is a 45 deg. bevel gear driving another 45 deg. bevel gear mounted to the apron, on a South Bend the concentric gear is a worm which drives a worm wheel, but in both cases the result is that when the leadscrew is turning a gear on the back side of the apron from which motion can be taken to drive the cross slide. The Atlas is limited to using the apron gears for cross feed but many lathes, such as the South Bend, can also use the apron gears to drive the carriage along the length of the bed, thus reserving the half nuts for screwcutting where greater precision is required. On the SB, when the half nuts are engaged a pin is shifted laterally in the apron to prevent engagement of the power feed via gears and vice versa, when the gear feed is engaged the pin is shifted in the other direction to prevent engagement of the half nuts. Leaving the half nuts disengaged, there is a lever on the front of the gearbox with 3 positions, center is neutral (where the half nuts can be engaged), up engages longitudinal feed of the carriage, and down engages cross feed. The drive when using the gear feed is; leadscrew drives worm which drives worm wheel, gear on same shaft as wormwheel (driven through an adjustable clutch) drives selector gear, selector gear is disengaged from all later gears in neutral, is swung into engagement with the carriage wheel gears in the up position,or is swung into engagement with a gear which drives the cross feed screw in the down position. Different rates of longitudinal or cross feed are selected through the change gear/gerbox ratios multiplied by a fixed ratio inside the apron. Stan said the ratio on his SB was a 1:4 reductio but that's relative to the leadscrew pitch. In fact the actual ratio would be 1:32 because it does't involve the leadscrew pitch at all. Still, it's convenient to thin of it as 1/4 the screwcutting pitch or 4 times the TPI. Looking at SB's "How to Run a Lathe" it appears that there is another reduction relative to power longitudinal feed of about 3-1/2 to 1 on the power cross feed. Does any of the above help? Anthony Berkeley, Calif. ------------------------------------------ Date: Sat, 19 Apr 2003 06:55:44 -0500 (CDT) From: dswrx~xxwebtv.net Subject: Re: Digest Number 1443 On the subject of half-nuts, threading dials and such, I would like to remind owners of the 6" (don't know if it applies to other size atlases) to check every once in a while the tightness of the screws holding the left hand leadscrew support. This keeps the leadscrew in alignment with the spindle. If it is loose, it can do nasty things to a threading project. 8-) Another thing to check once in a while... the threaded collar that adjusts the end play of the spindle. Leo (pearland, tx) ------------------------------ Date: Sat, 19 Apr 2003 19:21:25 -0700 From: "Bob May" Subject: Re: OBJECT OF A THREAD DAIL The thread dial just indicates where the lead screw is in relationship to the half nuts inside. When you are on a mark on the thread dial, the half nuts will engage the lead screw with no problems running down a slop of the thread of the lead screw while the half nut is engaging. The numbers are there as when you are threading finer threads, the lead screw needs to be in a particular alignment with the spindle and thus you will need to wait for that number to come around again. Try it for various threads on a bit of stock to see what happens. Needless to say, as the lead screw turns, the relationship between it and the table that gets driven by it change until the half nut is engaged and this little dial indicates where that contact is best made. The machinist that works the thread dial best will just flick the halfnut lever with a quick touch at exactly the right time and not apply any real force to the halfnut engagement lever to get the tool moving towards/away from the headstock. Bob May http://nav.to/bobmay bobmayx~xxnethere.com NEW! http://bobmay.astronomy.net ------------------------------- Date: Mon, 26 May 2003 12:44:45 -0400 From: "mertbaker" Subject: Re: 109 half nut > Has anyone found a way (easy), to repair or replace a 109 half nut??? > Mine is worn on one side, I was thinking of filling it with brass & > trying to re-thread it,, I don't know how to hold it straight to send > a tap through though....... > What is the thread size on the original Half nut?? > Any help would be welcomed, thanks in advance John One, maybe a couple of the epoxy/threadlocking co.s make a thread restoring product. I have used it to restore threads on a very worn cross slide nut on a lathe. The replacement nut was 35 bux, and the epoxy was only 5. I bot the stuff at an auto parts store, and it seems to be a standard item. I think the brand I got was loctite, but I'm not sure. Anyway, you clean the half nuts really well with a degreaser, smear the stuff on the worn threads, coat the leadscrew with release agent, and clamp the halfnuts closed. Wait the required time, (I think it was 5 min.), and open the nuts. Let it cure for the specified time (overnight?) and then trim off any excess. Supposed to equal grade 5 threads. You do have to follow the directions exacly for good results. Do not ask how I happen to know this. Mert MertBakerx~xxprodigy.net --------------------------- Date: Mon, 26 May 2003 16:30:15 -0400 From: "mertbaker" Subject: Re: 109 half nut > I have filled the half nuts with brass and have re-tapped (8tpi acme) to > keep the half nuts together I soldered them together with a 1/16" gap this > this worked OK I got the tap from "tracy tools" for £22.00 That would work on most half nuts, but not on the 109, which has the two halves cast into the halfnut lever, about an inch apart along the leadscrew. Mert MertBakerx~xxprodigy.net ------------------------------ Date: Sat, 21 Jun 2003 23:33:52 -0000 From: "jimmac70817" Subject: Re: thread dial indicator for craftsman 109 > Are there any thread dial indicators available that > will work on a Craftsman 109? Chris Hamel You can adapt the thread dial that comes on the hf 7x10. Buy it at Littlemachineshop.com Jim ------------------------------- Date: Sun, 22 Jun 2003 18:39:40 -0000 From: "jimmac70817" Subject: Re: thread dial indicator for craftsman 109 Chris Hamel wrote: > Jim, Thanks for the info. I checked out the web site and > found that it appeared I would have to order three > separate parts. Dial, shaft and housing. Is this > correct. Also, how much is involved in adapting this unit? Looks like you are correct on the parts, they used to sell it as a unit I think for 19.95. To install it you have to make a small bracket to set the vertical height. If you can get an original thats how I would go. If I had seen them at Bill's site I would have referred you there. Good luck Jim ------- Date: Sat, 15 May 2004 01:27:42 -0000 From: "jjjorg1" Subject: Re: Half nuts help Hi Jon. I replaced the half nuts on my 10f Atlas several years ago. I ordered a new set from Clausing Service Center in Goshen Indiana. The package did come with instructions. Basically, for my lathe, I removed the tailstock and lead screw bearing, opened the half nuts and slid out the lead screw (be careful not to let the feedgears and shift collar drop out from underneath the feedgear assembly when you remove the lead screw). I then removed the carriage and unscrewed the halfnut housing and removed it from the apron. Be careful not to lose the steel ball and spring. Then you remove the setscrews on the half nuts, slide the half nuts out, lubricate and slide the new ones in (after removing any flash), screw in the half nut setscrews, align the nut screws with the guide, place and grease the spring and steel ball, align and tighten the housing screws and check alignment and operation, place the carriage, leadscrew and gears and shift collar, lead screw bearing and tailstock, lubricate the lead screw and bearings, and test operation of the half nuts and make adjustments. There may be some variation with different designs and you'll be able to get more information from Clausing and the Atlas_Craftsman group here on Yahoo. Good Luck! Joel. ------