HF 9x20 Lathe chuck runout

[weejax]

I am getting around .003 of runout measuring about 1inch from chuck jaws. I used a number of different items (bar stock, drill rod, end mills) and got roughly the same result (some worse, .003 was the best i could get). I measured spindle bore runout and it is a little less than .0005. Is that acceptable? the chuck came w the mill, I have no idea what its provenance is. I took it apart and cleaned it. as you can see in the photo the jaws seem to meet nicely in the center. I did not mark the jaws when i took it apart and spent a while switching them out to get it to pull all of them to center. So, is .003 to be expected? Should i try and get new jaws? Or, get a new chuck? Thanks for the help!

 

[mickri]

3 jaw chucks have run out. Some people go to extreme lengths to get the run out as small as possible. I don't have the experience that a lot of members have. So my thoughts may be way off base. Even if the chuck has run out when you turn something it will be concentric with the lathe spindle. You say the spindle has a little less than .0005 run out. The parts you turn should have that same run out. Before spending $$$ you may not need to spend I would do a couple of tests to see what you get. Turn some round stock and check the run out.

 

[Ulma Doctor]

.003” is good, consider yourself lucky
Don’t think anything is wrong and go on with life.
As soon as you put a tool to the spinning work, you will turn a cylinder parallel with the lathes’ datum

 

[markba633csi]

Get a pack of cigarette paper and use it to shim workpieces when necessary. Normally we try to do as much "first operation" as possible before removing the part from the chuck.
Doing those two things will get you by. My chuck has the same error as yours and I can indicate stuff to less than a thou using Bugler paper
-Mark

 

[Nutfarmer]

If you need better than .003 use a 4 jaw chuck or if smaller work a collet. .003 is normal for a three jaw chuck. If you want better than that plan on spending 12. Hundred for an adjustable buck chuck.

 

[Marbles]

I make a lot of great parts with mine and I do not worry about runout.

I do light cuts and enjoy spinning stuff.

Don't go crazy, it's supposed to be a hobby and fun.