# Help - how to change leadscrew gear position on 101 6x18



## Pat of TN (Aug 30, 2014)

Hey guys, quick question.

I need to single-point a 24-TPI thread on my Craftsman 618, the 101/Atlas model. The gear chart specifies that the gear on the lead screw is a 48-tooth gear, but it is denoted with a B - meaning that it is toward the headstock.

This makes sense, seeing as how the other gear in the setup is also set that way; it is closer to the headstock rather than farther away - denoted in the chart by F, I believe.

I had it set up previously for feeding rather than threading, so the lead screw gear was in the F position, or away from the headstock.

Well, how in the world do I get the gear closer to the headstock on the leadscrew shaft? I'm stumped. The reason why - there is a spacer of some sort between the clamp for the forward/neutral/reverse arm, held in place by some sort of pin, I think. The gear won't go on the shaft any further than the F position.

So what next? I am not mechanically inclined, therefore I decided to stop and ask first. If the spacer needs removed, is it a straight or taper pin? I tried tapping it from both directions with no result. If the spacer does need to come off and I get it, how do I retain the gear on the shaft - it will be too far down for the bolt to hold it.

Or I could be off a bit and have it totally wrong. Either way - I'm throwing this problem to the wolves of H-M!


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## JOEZ (Aug 30, 2014)

Is this the Lathe you have in the link below?
http://vintagemachinery.org/pubs/222/1924.pdf


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## wa5cab (Aug 31, 2014)

Pat,

Go to Downloads.  Scroll down and click on Atlas/Craftsman/AA, then Atlas/Craftsman Lathes, and finally Atlas Lathe Manuals.  First file at the top of the list is the manual on the Craftsman 6" 101.21400.  Download that manual.

On Page 7, which is the 13th page in the file, you will find the change gear assembly.  This has nothing to do with the FWD-REV Tumbler Assembly shown on the previous page #6.  At the top of the page is the exploded view of the lead screw.  It is not drawn quite right, and I will fix that in a few days.  Items # 136, 137, 142 and 224 should have been drawn at the other end of the Lead Screw 141, between it and Bearing 140.  You have to slide them on from that end of the lead screw.  Or actually you would probably bolt the left Bearing 136 to the bed first and then slide the lead screw through it, through Collar 142 and finally through Bearing 140.  Collar 138, which is pinned to Lead Screw 141 and is not normally ever removed, goes against the left side of Bearing 136 which is bolted to the left end of the bed.  Below, just above where it says 143 CHANGE GEAR BRACKET ASSEMBLY, you will see Gear 147, Spacer 235, Washer 76 and Cap Screw 149.  If installed in the order shown, Gear 147 would be in the B position.  To put the gear in the F position, remove the four parts, slide on Spacer 235 first, then the gear, washer and cap screw.

Robert D.


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## Pat of TN (Aug 31, 2014)

Guys, I'm having trouble downloading items at the moment, so it'll be a bit before I can do that. Sorry about that.

But trying to wrap my head around what you're saying Robert - do you mean I'll end up having to remove the lead screw? That's a little frightening to me.


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## JOEZ (Aug 31, 2014)

Hey Pat
    Once you are able to download the link. You can follow the instructions Robert gave you. You do not have to take the lead screw off. It does make a easier job of setting you gears up if you take the change gear bracket assembly off.


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## Pat of TN (Aug 31, 2014)

Okeydoke, that does my heart some good! Sorry for the misunderstanding folks. I'm still unable to download that file, I may have to do a little fiddling with my computer or something. For now I'll probably have to tear down my current job I needed to single-point, but it's no big deal. As long as it doesn't bend!


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## JOEZ (Aug 31, 2014)

Pat of TN said:


> Okeydoke, that does my heart some good! Sorry for the misunderstanding folks. I'm still unable to download that file, I may have to do a little fiddling with my computer or something. For now I'll probably have to tear down my current job I needed to single-point, but it's no big deal. As long as it doesn't bend!


Can you open this link below? 

http://vintagemachinery.org/pubs/222/1924.pdf


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## wa5cab (Aug 31, 2014)

Pat,

If you have something set up in the chuck I can't recall any reason that you would need to tear the setup down.  

As Joez already wrote, you do not need to remove the lead screw.  Although I think the lead screw in the 6" is the easiest to remove of all the models (loosen one set screw and pull it out).

In the left end of the lead screw there should be a hex head bolt (cap screw).  Remove it and the flat washer on it.  Left on the lead screw should be a gear and spacer (or spacer and gear) and a collar that is pinned to the screw.  Remove the gear and spacer.  Don't lose the woodruff key that removing these will expose.  Do not attempt to remove the pinned collar.

Try to open the link Joez posted.  Unless you ever clicked the "Do this automatically..." button, that should bring up a dialog box offering a choice of 'Open with' or 'Save File'.  If it doesn't and also doesn't open the file, the problem is probably at your end.  If it does one of those things, when you have time try Downloads again and tell me what happens or what kind of error message you get.

FWIW, I edited the page showing the lead screw and parts, for clarity.  I'll upload the revision in a few minutes.

Robert D.


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## Pat of TN (Aug 31, 2014)

wa5cab said:


> Pat,
> 
> If you have something set up in the chuck I can't recall any reason that you would need to tear the setup down.
> 
> ...



Okay, that's not too bad! Aha... mainly I took my part out so I could set back up for other projects I had in mind while I waited to figger out how to change the LS gear. I orta be able to indicate it back in to single-point it.

Your instructions sound pretty easy, I'll give it a shot tomorrow some time. Thank ya!

About the downloads problem, it's my computer. I can start to download them fine, but it will get to a certain point and just stop. It'll leave the file on my desktop, but it can't open since it's not fully loaded. I'm probably paying the price for running without virus protection. On top of that, my Adobe is outdated so I can't just view it, and my internet's too slow to update it! Catch-22.

Thanks, guys. I will report back with results when I give it a try (hopefully good results!)


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## wa5cab (Aug 31, 2014)

Pat,

The Acrobat Reader is pretty small.  First couple of versions that I had were probably downloaded with 56K or slower modems.

Robert D.


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## Pat of TN (Sep 1, 2014)

Robert, it worked perfectly. I feel a little silly now, it being so simple, hah! In my defense, though - the previous owner never threaded on the lathe for the 20-some-odd years he had it, so the spacer and the pinned piece looked like they were solid. A pair of vise-grips popped it off lickety-split, now it just slides on and off... so... problem solved! Thanks a bunch.


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## wa5cab (Sep 3, 2014)

Pat,

I was hoping that would turn out to be the case.

If you haven't already, be sure that you read and follow the brief installation, setup and leveling instructions in the manual.  Including bolting the stand securely to the floor.  It's my opinion that Atlas included all of that as part of the machine design.  

Robert D.


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## Pat of TN (Sep 3, 2014)

Yep, I will look at that when I get the chance... I have chatter problems every so often, and that may be part of the issue. The lathe sits on a wooden cabinet/dresser thing on a wooden floor, not bolted down to anything... but considering, it's not bad for an at-least-60-year-old lathe!


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## wa5cab (Sep 3, 2014)

Is the lathe bed at least bolted to the cabinet?  If so, how thick is the cabinet top?  Should be a minimum of 2" (1-3/4") solid  or built-up hardwood.

Robert D.


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## Pat of TN (Sep 3, 2014)

wa5cab said:


> Is the lathe bed at least bolted to the cabinet?  If so, how thick is the cabinet top?  Should be a minimum of 2" (1-3/4") solid  or built-up hardwood.
> 
> Robert D.



Nope. :S It's exactly the same as the previous owner had it for a long time, pretty much. Just sitting on the cabinet. The top is... oh... 3/4" thick... I've thought about making a different table for it. Robert, you might've given me a bit of a kick-start.

Correction - it is bolted to a steel table top, somewhere around 3/4" thick. That's sitting on the cabinet.

The previous owner is the instructor for the machining course I just graduated from, I figured he had it mounted suitably, but... his abilities have come into question...


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## wa5cab (Sep 4, 2014)

OK,  The steel plate should also be attached to the cabinet top (probably is, I guess).

RD.


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## SG51Buss (Sep 4, 2014)

If that tabletop is 'office desk' construction, it may be simply 2 sheets of 18 or 20 gauge sheet steel with a honeycomb core.  Those kinds of desktops can be fairly stiff, but the question then becomes "How do the bolts secure to the table?".  Sheet metal screws catching only the top sheet, or bolts that pass through and try to crush the honeycomb?


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## Pat of TN (Sep 4, 2014)

No, the plate isn't attached to the table. Not sure how the steel piece is constructed, but it appears solid around the perimeter. I think the bottom is recessed a bit in the middle. The lathe itself is held to the plate via bolts, I believe. Not sure how, whether it's a bolt and nut or threaded into the steel... but that just sits on the top of the cabinet. Like I said, that's how the previous owner had it.

I am thinking about making a new table for it, though. I'll have to look into the cost of a couple 2x4s, I do believe.


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