3 jaw

I lucked into a Bison 3 jaw centering chuck.... Just playing with it I was not able to get much movement on a .0001 indicator...I do not use it..
My business I need to have reversing jaws as I hold the inside and outside of my parts, so it just sits there...It fits the 1 1/2-8 threaded spindles...
 
wish I woulda known u had an extra a week ago!! took this one down to size yesterday and douched it out in the parts washer...heading out shortly to put it back together, relube and maybe run a dial indicator on it if I get too it today.
 
well somethings not right :( im running like 33 thous out on a piece of rod... and ive tried a few different items now all about the same. all jaws are in there proper spots according to the stamped #. im at a loss.. im going to try turning the mounting plate 1 set of holes but I cant see how that would matter since i machined the thing on my lathe... and my spindle nose is withing 1 thou so its not my old lathe
 
well I tinkered around took another cut off the face and its down to about 6 thou... not sure what the standard is for these shars chucks?
 
Website says .003". Unless the one you got has manufacturing issues .006" is way too much for being brand new, something is not right.

Have you checked to see if the register on your spindle has a close fit with the register on the chuck backplate? It should not have any slop.

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as you can see in the pics above the backing plate was much thicker then the length of the threaded spindle so I took approx. .500 off of it and removed a few threads so It would go back over the shoulder you have circled. im going to rotate it again on the plate and see if that gets me anywhere. thnks
 
I hope that when you bored out the threads in the back plate that you knew that you were working on the chuck register. The unthreaded portion in the open side of the back plate should be no more than 0.0005" larger than the diameter of the register. The register and not the threads is what centers up the chuck. You should still be able to just make out the thread in the bored-out region.
 
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im within 4thou.. its possible that ive took a bit much off the ring that fits into the inside of the chuck... I think im pretty close on the register.. if at some point when I have more knowledge and better tooling feel I can do better I will get another backplate and try again. the instructions don't say anything about shortening the backplate but it seemed kinda stupid to be sticking out that far when I didn thave to be. I had posted on here for some wisdom but got impatient and wanted to play with my new chuck... anyhow 4 thou is what I got. Ill have to deal with it for now.
 
within 4 thou on a piece of drill rod in the chuck that is.. but my indicator is only .001 readout. and im thinking I should have a last word type for these operations?
 
If you bored out the register too big on the backplate, no need to buy another. Bore it out bigger, sleeve it, then you can bore to size again.
 
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