# 6" Atlas spindle removal, (& bearing replacement)



## Deanofid (Nov 28, 2009)

Hello all;

This write up deals with spindle removal and bearing replacement for Atlas 618 
plain sleeve bearing lathes. It may come in handy for someone needing new 
bearings, but the same procedure, (minus the bearing replacement) has to be 
done if you simply need to replace the drive belt on the lathe, or if you need to 
replace the thrust bearing, or step pulley bushings.

After getting my new/old lathe torn down, cleaned up, and put back together, I 
made some test cuts to get a feel for the general health of the machine. It cuts 
well, but when parting off, I can actually see lateral movement in the work piece, 
and watching closely, I can pretty much tell it's from the old bearings.

I've had the spindle out of the lathe a few times already, and from looking in the 
head stock bore with the spindle removed, I could see some scuffs on the front 
sleeve bearing. I ordered new bearings from Clausing, and they showed up a few
 days ago. They only took about a week to get here, counting a weekend. They 
shipped the same day I ordered. Good service. 
Today was a good day to get them put in so I can start seriously setting up this lathe.

I took pictures when I removed the spindle and put the new sleeve bearings in. 
Some were taken when I first got the lathe, and it's pretty dirty. Some were taken 
after everything had been washed in solvent. I had completely disassembled the 
lathe, with the exception of the micro dials, which gave me a good idea of the shape 
of things.

I figured some pictures and words might come in handy for other folks that may have this lathe.









To start with, pull the power cord on the lathe. Remove the lock collar on the 
back end of the spindle. In the shot above, it's already been removed. It has a 
single set screw in it, so back it off a turn, and remove the collar. The collar is 
round, and has no flats or anything to put a wrench on. I'm not going to tell you 
to put pliers on it to remove it.. Go your own way on that. Some primate had 
used a hard hammer on the back end of this spindle in the past, so the collar was 
hard to remove. It is a right hand thread.

There is a soft BB in the bottom of the hole for the set screw so the screw doesn't 
bur the threads on the end of the spindle. Don't loose it.









Then pull off the main spindle gear, and remove the Woodruff key.









After that, you can pull of this thrust collar.









It should look like this when you have the pieces on the back end removed.
Now would be a good time to slack off the two big screws in the bearing caps. 
You can see one of them in the picture above, and there is one on the chuck end 
of the spindle, too. Back them off until they are loose, then just barely snug them 
down. The idea is to get the spindle out without the bearings following it at the 
same time.









Now, get a look at the bull gear lock pin. Finding it is the easiest way to locate the 
the lock screw for the bull gear. There is a screw at the edge of the bull gear in this 
shot. That is for oil. Rotate the bull gear 180 degrees, and you will see another hole 
opposite the oil hole just mentioned. 









When you find the second bull gear hole, reach way down to the bottom of it with 
a 5/64" allen wrench and loosen the set screw a couple of turns. That set screw is 
only there to keep the bull gear from sliding along the spindle, but has to be loose to 
get the spindle out.









Now, unless there are other problems, (I'll save that for later), you should be able 
to slide the spindle toward the tail stock. At this point, you only want to pull it out 
of the nose end of the head stock about 3/8", until you can see the Woodruff key, 
as in the picture above.

Take that key out, but don't pull the spindle any farther toward the tail stock end of 
the lathe yet!









When the key is out, check very carefully at the corners and ends of the Woodruff 
keyway. Use a fine file to gently remove any burs that you see. Then gently turn 
the spindle 180 degrees and look for the place where the set screw in the bull gear 
pinched on the spindle shaft. File that spot down too. These two places do not run 
in the spindle bearings, so filing them won't hurt anything in that respect. The bull 
gear sits over the top of both of these spots, and is always in the same relationship 
to them, so there is no danger of the filing job doing any harm to it, either.

If you should just yard the spindle out of the head stock without doing the above, and 
there are burs at these points, you'll score the bearings. I'm replacing the bearings right 
now, but what if I just needed a belt? You have to take the spindle out to get a new belt 
on too. You don't want to ruin your bearings just to replace a belt, so check these two 
points carefully.

Once those burs are dressed down, reach in with a tissue and clean off any filings, and then 
you can pull the spindle out slowly.









As you pull the spindle out, catch the thrust bearing. At about this point, the spindle 
diameter will change at the nose end of the head stock. It gets smaller, so don't let 
the spindle drop onto the bearing.

Note the small screw in the second pulley groove. That is for oil. Nothing else. It 
lubes the step pulley bushings. (It's supposed to be oiled each day that you will use 
the back gear.) 








Keep pulling the spindle out, first grabbing the step pulley, then the bull gear, so they 
don't fall down into the head stock cavity. 









Now, I actually did have trouble with this one. The bushing you see on the 
spindle in the shot above is supposed to stay in the step pulley. I had to tap 
the spindle out with a piece of wood because the small bushing was stuck 
on the spindle. There are two of those bushings, and they should both be 
pressed into the step pulley. They allow the pulley to spin on the spindle 
independant of the bull gear when you have the back gear engaged. 

I soaked this for a while in solvent, and the bushing came off pretty easy. It was 
pressed back into the step pulley, and all is well.









In this shot you can see what I'm talking about. That bushing on the spindle was 
supposed to stay in the pulley.









With the spindle nice and clean, I tried the new sleeve bearings to make sure 
they were the right size, before I take out the old bearings. In this picture, the 
tiny circle near the larger bearing is where the bull gear set screw has raised a 
mark that I was talking about earlier, and this is one of the things that had to be 
filed down before pulling the spindle through the bearings. 









To get the old bearings out, make sure the bearing cap screws are loose, and 
use a piece of wood or plastic to tap them toward the inside of the head stock. 
Both the front (big) and rear (small) bearings would move a little by hard pressure 
with my thumb, but I couldn't press far enough into the hole to get them all the 
way out. So, tap, tap, with something soft. 









Guess which one is the old bearing? 

The old one, (ok, on the right!) still has factory paint on it, so it's been in there 
a long time. You can see that it's taken a beating a few times too, by the marks 
left from someone whacking on the end of the spindle without removing the 
Woodruff key. I expect it's 50-60 years old. Reading on lathes/uk, it says there 
were no more plain bearing lathes after around 1957-59, if I recall. So, it's done 
it's job for a long time.  

There are some straight marks in there that are no doubt from previous spindle removal, 
but there is also a rather large spot of radial scuffing on the far right, which looks similar 
to what you see sometimes in crank bearing shells in car engines. Many miles.

Putting the new bearings back in is just a matter of cleaning out the head stock, oiling the 
outside of the bearings, and pushing them back in. If they seem a little tight, make sure 
the bearing cap screw are loose first, then try again. If they are still too tight, try this, but 
only if you really can't get them started straight without doing so;

Screw down the bearing cap screws until you feel them just barely start to get tight. 
I'm talking about the point where you feel them touch the top of the hole as they 
thread in, where if you screwed them in any further, they would start to squeeze the 
bearing caps. (Don't screw them down hard. You'll break the caps.) Then back out 
the screw just a touch, so it is free, like 1/20 of a turn. Use a thin wedge of wood, and 
tap it into the parting line of the bearing cap to spread them just a thou or two. Be careful. 
Don't hit the head stock casting with anything metal. Use a tiny plastic headed hammer 
to tap in the wedge, and then just a little bit. This will spread the cap enough to let you 
get the bearing started in the bore straight. Then you should be able to put a small piece 
of wood on the end of the bearing and push it in with the palm of your hand. I had to 
bump it in with the ball of my palm to get the big one in all the way. The small one went 
easier. Then pull the wedge(s) out and make sure the cap screws are loose again.

Oil up the spindle with light oil, and put it back in the head stock to see that it fits without 
any of the other gears/pulleys and other things. It should spin freely. Take it back out 
and start putting all the parts on it as you feed it through the bearings, taking care not to 
knock it on the bearings as you do so. Don't forget the Woodruff key that goes in the 
bull gear. 










After you get it put back in, if you are me, you will immeadiatly take it back out 
and put the belt on. If you are not me, you will put the belt on first!! I'm getting 
pretty good at removing it, by now.

Put the belt on before you put on the thrust bearing...

When you have the spindle in, through the bull gear, step pulley, and thrust bearing, 
replace the thrust collar on the back end, (the small end of the spindle), then the 
main spindle gear and its' key, then screw on the lock collar. 

Atlas says to run the collar up to the face of the spindle gear, then tighten it the space 
of 1-2 teeth of the gear, rotating the spindle as you do so. They say it should have 
some resistance, so when the spindle warms up it will not have any end play. Tighten 
the lock screw on the collar, (make sure that the thread protecting BB is still in the hole). 











Last step is to tighten the bull gear lock screw. Put the bull gear right up against 
the step pulley, but not riding hard against it. The bull gear and the step pulley have 
to be able to turn independently without rubbing against each other Tighten down 
the bearing caps snug, but don't put all your might into it. Check to see that the 
spindle still turns after tightening them. 

To determine how tight to make these, I put a chuck on the spindle with a piece of 
1 1/2" round stock sticking out about 2". Then put a DI on the back side of the round 
stock, and pulled the stock toward the front of the lathe and then toward the back of 
it and watched the readings. I tightened down the bearing caps until I had what I 
wanted, which, for now, was about one thou at one inch from the chuck face. How 
much you cinch down the caps is up to you, but I would say if you had to use all the 
strength in one had on a screwdriver to get what you want, it may be too much. The 
bearings caps are a pretty sturdy part of the casting, but they will only take so much! 
I will say now, that this is just a guess derived from prior practical mechanical experience. 
I'm no engineer. I couldn't find any solid info in the Atlas material available, and Clausing 
didn't have a firm number for me as to torque when I called them for parts.









Sometimes, a practical test is the best indicator of how things are working. The oil 
cups were filled with oil, set the lathe to one of its higher speeds, and let it run for a 
half hour to get the bearings and spindle warmed up, keeping an eye on the oil cups 
to make sure that they were oiling a bit. Also, every five minutes or so, I put a finger 
on the bearing caps and the spindle nose, (lathe off!) to see if there was any undue 
heating. They never got much over what I would call mildly warm, so the preload and 
cap tension is probably good.

After warm up, I checked the spindle with the DI again, then tried a parting cut. The 
tool was only run in about .050", but if it will do that without any chatter, I'll call it good. 
Parting cuts are about the hardest thing on a lathe, outside of knurling, maybe, and if it 
will part off without chatter, it should do fine.

Once the bearings have run in with a few hours of working time on them, I'll check the 
run out again with the lathe warmed up, and make any adjustments I think it needs. 
It's not likely I'll have to do this again in my lifetime, though if I'm lucky, I'll get to replace 
a belt or two.

If you got through all this, thanks for having a look!

Dean


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## Twmaster (Nov 28, 2009)

Magnificent! I'm hoping to have time to mount my 618 tomorrow or Monday....

Heh. I thought I was the only ding-dong that forgot to do things like put the belt back....


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## Deanofid (Dec 2, 2009)

Thanks Mike!

This thread went over about as well as a screen door in a submarine. 
Pretty limited scope. Glad you liked it.

Dean


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## Artie (Dec 2, 2009)

aaawwww Dean.... I found it VERY interesting... I just didnt post.... I really dont know WHY you cant read my mind... sorry mate I should have piped up and said how much I enjoyed it.. (as with all things mechanical.. I love 'how to' articles..) 8)


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## ksouers (Dec 2, 2009)

Dean,
I, too, thought it was a great write up. Lots of details and warnings about the gotcha's are always helpful.
Thanks.


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## Deanofid (Dec 2, 2009)

Well, thank guys. As always, I appreciate it.

Dean


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## dsquire (Dec 3, 2009)

Dean

Thanks for the very detailed write up. While it may not be exactly what everyone else is using, just paying attention to all the little bits about burrs, bb's, oil screws, ect. are good general information. If a person reads a few of these articles then they will certainly have a much better idea of what they might expect when they tear their own machine down for a rebuild or repair. First rate article Dean. :bow: :bow:

Cheers

Don


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