Chuck on 6 inch Atlas

C

CAW

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For some reason, the three jaw chuck on my Atlas 6 will not hold stock straight. I put a short piece of one inch aluminum in the chuck and when turned on it appears to wobble. The chuck is an M6-845B Atlas. May be original to the lathe.

This same phenomenon happens with all other round stock. Spindle itself is tight and true.


Will disassembly and cleaning work or do chucks wear out?


Curtis
 
Does the stock wobble at an angle, or is it straight lengthwise but just offset from center? The first thing I would look for is a bur on one of the chuck jaws. I have a 12" Atlas, and the 3 jaw on it has a wobble where it is offset from center. I just got that lathe going, so I haven’t had a chance to look at it. I don't know if it is an Atlas or not. It holds stock tight, so if I can't find a cause in the jaws, I plan on re-attaching the backing plate so that it runs true. That is so long as the offset is consistent.
 
It appear to me that the jaws are not closely uniformly, which causes the round stock to get slightly out of straight alignment.
 
Start a project, clean the chuck up, remove any burrs on the jaws, put it back together and then get a piece of drill rod and an indicator and check the runout.

If its as bad as you say, do a little restoration on it first, it may save you time in the end.

Post the restore project here, you'll get lots of help.
 
A one inch piece of stock is pretty short. If you are working on 1/2 its length then not much is being grabbed by the jaws. Could be you are just not ensuring it is straight as you tighten it.
If you chuck up something 6 " long with only 1" extending out the jaws does that run true?

Cheers Phil
 
Phil makes a good point here and to add to that the best thing you can do for your Atlas lathe is buy a beefier chuck it does not have to be an expensive one just something beefier with larger jaws than the stock one. keep the stock one for tiny parts. Ray
 
Maybe the jaws are not in their proper locations....They should mesh when closed if they don't they are probably wrong HTH
 
Thank s for the suggestions. Problem has been resolved. I took the chuck apart and cleaned it in the parts washer and then wire brushed the parts. The jaws had a bunch of built up crud, which affected the seating of the round stock in the jaws. Put it back together, took a piece of 3/4 stock and inserted it several inches into the spindle. Doesn't wobble anymore and the run out was only about .004 in one foot, which is way less than before.

Curtis
 
Glad you took the time to clean it up. I find older chucks need a cleaning before anything.
 
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