Standard Modern 16-60 Lathe chatter problems

danleereed

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Good afternoon folks,
I have just bought a used lathe. I have change a few bearings in the cross feed slide and also in the compound. It started out with .150" backlash in it. Now it has .015" backlash. That was as tight as I could achieve so far.

I then tried to turn a 1.5" piece of 1018 crr. I had about 2.5 inches sticking out of my 4 jaw chuck. I have tried carbide insert tools and ground HSS tools. With the sharp pointed HSS I ground it does better but still unsatisfied with the finishes. The chatter is horrible. Not a loud whiney sound, but more like a low vibrating rubbing sound. I have benn taking from .01" to .02" per cut. And I have tried from .0015 per rev to .004 per rev with not much change in finish. I have tried 100, 240, 320, 400, 800, 1000 RPMs and still it chatters.

I have tightened the gibs on the cross and compound to where its not to easy to move them, but I am sure they are tight. A little tighter than I would like to leave them though.

I found that the chuck mounting bolts took a 1/4 turn on every one to tighten down, but no change when tightened.

Where should I be looking or what items should I check to find out the cause of the issue.

I found on thread here , pretty long one about a grizzly and chattering. I have checked everything except my bearings and main shaft. Is there a procedure to take off the chuck and check out the shaft it mounts onto to see if I have a problem?

I may have left out some info but I tried to get it all in here, Thanks for look. Any help would be appreciated.

Thanks,
Dan Reed
 
So, an update.

I took off the chuck and it was gummy stuck to the mount. I had to use my small deadblow to tap it as I hand spun it and it came off eventually. I found a ton of shavings and debris inside so I cleaned it all out and reinstalled the chuck.

I was hoping to get a good cut, but no. I had a piece of 1.5" Cold roll in the chuck and I put an indicator against the shaft then proceeded to push the shaft towards the indicator. It moved about .005".

Next I put the indicator near the outside of the front face. I gave the shaft a push, just leaning on it and the chuck face moved about the same .005 - .006".

I guess this weekend I will be getting into the main gearbox. Seems I may need to get new bearings. I had the top off the other day just looking in to see how clean it was. It was pretty clean but I didn't dig around in there to much.

Well, I am anxious to see what you guys think about the issue. Maybe someone has experience with changing the bearings out. And the signs of wear.

More to come as I get more into this weekend. I may just order bearings tomorrow so I can go ahead and replace them while I have it tore down.

Thanks,
Dan Reed
 
You might be able to adjust the bearings if it has taper bearings. I'm not familiar with your lathe, but many lathes have a pre-load nut on the back end of the spindle, to set the tension on the taper bearings. You got nothing to lose by trying it first, before ordering new bearings.
 
You might be able to adjust the bearings if it has taper bearings. I'm not familiar with your lathe, but many lathes have a pre-load nut on the back end of the spindle, to set the tension on the taper bearings. You got nothing to lose by trying it first, before ordering new bearings.


Thanks for the info Xalky. I spent last night going over the drawings in the book I got for it. I am going to try to tighten it up this afternoon. I have attached a picture of the shaft and bearings drawing. Looks like it should be a piece of cake.

lathe main shaft.JPG
 
Here's a pic of the beast I have. It's a little ugly but it just needs a little love and affection...

lathe 2.JPG
 
Standard Modern is a very nice lathe. It would look better painted up. I wish I had a better large lathe like that. I have a Hardinge HLVH small lathe,but my 16" is a Grizzly. It works fine,and is accurate. But it is just not a real industrial lathe.
 
Good find, very nice lathe. It sounds like the lathe needs to have the pre-load on head stock spindle bearings adjusted. And hopeful during the time when it was out of adjustment, no damage to the “Timken” bearings was done. I would definitely change the oil in the head stock cavity with fresh oil after all is done, just in case metal particles are floating around in the thing. In your pic of the breakdown, I see yellow highlighted on the far left. That to me looks like the adjustment collar to set the correct pre-load. Hopefully you have the manual and it goes into all the detail of adjustment. Please keep us posted and Good Luck.
 
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Well I busted open the gear box a few minutes ago. I tightened it up a little bit. I am worried about making it to tight now. I don't have a book with instruction on the procedure, but I am going to google for one now.

How would I know if I tighten up to much? Is it similar to a car wheel bearing? I know to tight is bad, so I need to have it just right I'm sure. I just don't know what that is.

Thanks for the responses and suggestion thus far.
Dan Reed
 
I would call SM directly and not search the net. The net can be a misinformation adventure. My lathe (different make) adj is take off the chuck and take of the drive belt. So now the spindle has no extra load or drag on it. Mount the face plate on the nose of the spindle. Give the FP and good snappy turn. If the spindle free wheels with one rev, then the pre-load adj is good. Please remember this adj is for my lathe not yours, but hopefully will give you a better idea of the pre-load adj process. And this is not like adjusting a wheel bearing on a car or motorcycle. Any end shake in the head stock spindle of a metal lathe IS NOT tolerated. Any play will cause chatter and too tight will get hot and cause damage, you want somewhere in the middle, get the idea, that's your challenge for today…Good Luck.
 
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Well I busted open the gear box a few minutes ago. I tightened it up a little bit. I am worried about making it to tight now. I don't have a book with instruction on the procedure, but I am going to google for one now.

How would I know if I tighten up to much? Is it similar to a car wheel bearing? I know to tight is bad, so I need to have it just right I'm sure. I just don't know what that is.

Thanks for the responses and suggestion thus far.
Dan Reed

Dan,

If you can't find a book or more sage advice than I can give I'd feel good about setting it up like we do Timken bearings on H-Ds here. The spec calls for .003 - .005 endplay. I've always set them up @ .004 and they've seemed to like that for several decades. You can always run it in for a little while and see how warm it gets.

Hope this helps until someone more knowledgeable than me about this particular machine can pipe in though I don't believe that will damage your spindle or bearings in the least.
 
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