4 jaw chuck mounting

Nigel123

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After owning the lathe almost 20 years discovered the 8 inch 4 jaw chuck is only bolted on (no recess machined)
In my defense I seldom use it took it apart to clean it for the first time (I think getting old)
I set it up to machine it, the run out is about 0.0005 thou but I noticed the countersunk cap screws are set deep
there is only about 3/8 inch of meat left so if I machine 3/16 off its getting a little thin
I have come up with some options
Leave as is
Bolt and pin a spacer and machine it to fit the recess in the chuck
Hope I explained this okay
what are your thoughts
 
There's nothing really wrong with having no recess on a chuck mounting, especially with a 4-jaw
Why make more work for yourself?
As long as the bolts are tight you should be fine; 5 thou runout is not bad- or did you mean 5 tenths?
-Mark
 
Last edited:
.0005" runout is about as good as you will ever get it, and the 4 jaw does not care so much about running true. I would make sure the fasteners are holding the chuck tight to the spindle, and then leave it alone. I understand you have only used the 4 jaw for the last 20 years??? Well then, maybe you are also good for the next 20...
 
There's nothing really wrong with having no recess on a chuck mounting, especially with a 4-jaw
Why make more work for yourself?
As long as the bolts are tight you should be fine; 5 thou runout is not bad
-Mark


5 tenths, not 5 thou'. Even better...
 
5 tenths, not 5 thou'. Even better...
.0005" runout is about as good as you will ever get it, and the 4 jaw does not care so much about running true. I would make sure the fasteners are holding the chuck tight to the spindle, and then leave it alone. I understand you have only used the 4 jaw for the last 20 years??? Well then, maybe you are also good for the next 20...
 
Thanks for the replies advice
Not sure if it was acceptable to run this way and have avoided machining cast
Had it setup to do when I noticed the thickness and decided to post for answers
Very happy I did and grateful for the advice
My day is suddenly a lot brighter thanks Nigel
 
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