Spindle Thread Damage

G

GRP

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Hello All,

I recently took the chuck off of my lathe for just the second time and this time I noticed that there is some damage on the spindle threads.

There are a few dents and dings on some of the threads and there is a section of thread about half an inch long that looks a little ragged. I have a Grizzly G0602 and I'm thinking that since on this machine the chuck registers against a face behind the threads that this might not be too big of a deal.

I don't really know what I'm talking about though, so I could be wrong.

I'm an industrial repair tech by trade, so I'm confident that I could file the threads a little to remove any high spots without causing more damage, but will this cause run out in the chuck? Should I just leave it alone? I've heard that spindle damage is not great for lathes...

Also, the face that the chuck seats against is fine and the taper on the inside of the spindle is fine.

Thanks!
-Rick

PXL_20220415_194144680.jpg

PXL_20220415_194323394.jpg
 
I think you are all good. I think it could only help to file the high spots off of the threads. Like you said, the are that the chuck seats is in great condition, which matters more than anything

Bernie
 
You want to remove the high spots that are outside the profile of your threads. Also, remove the abrupt transitions at the rear. There is nothing worse than getting something caught on the sharp edges to ruin your day. The big question that I have is, did it come like that, or was it something that you did?

Anything that you mount uses the flanks of the threads to push the device up against the flat vertical portion of the spindle (which is the register). Anything OUTSIDE of the plane created by the flanks (like the ding in your second photo) can cause runout on everything mounted.
 
Do nothing more than a very light filing or stoning of those surfaces.
And you can ignore it completely.
 
Serious spindle thread damage is a big issue. Your's is not serious. . . As already stated, the back of the chuck where it meets the spindle is what matters. It is general practice when a chuck is mounted, both male(spindle) and female(chuck) threads are properly cleaned and lightly oiled. If the chuck screws on freely, it is fine, leave it alone. If there is any drag, touching up the rough spots can be in order. But only removing the rough spot, do not take it any further. A three square file is fine, just be sure to remove any filings. Any runout of the spindle can be checked with the chuck removed. Any runout of the chuck is the nature of the chuck and is tested and treated seperately. Spindle runout is a problem, chuck runout, within limits, is not.

.
 
Thanks for the replies.

I'm not sure what caused the damage. I cant think of anything that might have happened when I was changing chucks. They came off and went on easily. I didn't check when I received the machine, should have looked closer when I had it off the first time.
 
I may have come that way. Just bad factory work. Mike
 
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