A Question about Turning or Modifying Toolholders

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chatter chatter cut cut

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recently purchased an er32 collet set and collet holder all looks ok. however the 4 in shaft collet holders shaft is too large to fit inside the 3 jaw chuck and the headstock . is it possible to turn the shaft down to fit or is it too hard? i can return it but i think the shipping will equal or more than the original cost.thinking to turn it to a diameter that will fit and cut the shaft to about 2in. all suggestions appreciated.
 
pictures may help here

often tool holders are softer than cutting tools.
it may be doable, but you may need to do the work between centers to keep concentricity
 
I'm not sure why you want to use a collet holder like that. Even if the holder and collets are perfect your TIR won't be any better than the chuck.

Most who use collets in their lathe either use ones that match the spindle taper + a drawbar, an adapter like this or something like this, which mounts on the spindle in place of the chuck. These approaches will perform much better in terms of TIR.
 
For what it is worth, I bought the ER32 chuck for a 4" from LMS and mounted it on my mini-lathe. I was and still am impressed with the very low TIR. Under 0.0003" with 1/2" and 0.375" dowel pins. The chuck taper itself measured 0.0001", it barely moved the DTI.
 
Yes you really want a Morse taper collet chuck and drawbar for least runout
Better yet, one of those faceplate style collet chucks that would allow you to pass work all the way through (no drawbar)
 
I used a straight shaft in a 4 jaw chuck for years. I bought it to use ER32 collets that I had for the mill. Had very low TIR, but work holding was very limited, a couple of inches. Best bet is to get a spindle mounted colet chuck for longer work holding. Morse taper might be better but will be limited in length.
 
Chewy said:
I used a straight shaft in a 4 jaw chuck for years. I bought it to use ER32 collets that I had for the mill. Had very low TIR, but work holding was very limited, a couple of inches. Best bet is to get a spindle mounted colet chuck for longer work holding. Morse taper might be better but will be limited in length.
Click to expand...
I have a set of Morse-taper collets I bought years ago. I don't use them much because they aren't pass-through.
 
I really appreciate all the responses, thank you. this hobby lathe has no morse taper.and id of about .875 ,the collet holder shaft is hollow. id .657 od .995 . my plan is to chuck the collet shaft between centers and to turn to a diameter to fit in the chuck. and then shorten the shaft so that the collet does not stick out more than is necessary.and possibly bore the id to pass 3/4 in bar.however all is presently on hold till the back problem is resolved.
 
chatter chatter cut cut said:
recently purchased an er32 collet set and collet holder all looks ok. however the 4 in shaft collet holders shaft is too large to fit inside the 3 jaw chuck and the headstock . is it possible to turn the shaft down to fit or is it too hard? i can return it but i think the shipping will equal or more than the original cost.thinking to turn it to a diameter that will fit and cut the shaft to about 2in. all suggestions appreciated.
Click to expand...

Try a file test to test the hardness. Mine are pretty hard. I did cut mine down to 3'' but I used an abrasive cutoff wheel.
 
@chatter chatter cut cut ,

Does your lathe have a threaded spindle?

If so maybe one of these would fit:
https://bealltool.com/products/turning/colletchuck.php

I previous wrote about them here:
https://www.hobby-machinist.com/threads/is-there-a-definitive-article-on-collets.36227/post-308310
and here:
https://www.hobby-machinist.com/threads/is-there-a-definitive-article-on-collets.36227/post-308552

As you can see in the second post above, on my SouthBend 9" this system allows me to put stock thru the spindle, right up to the spindle ID of 3/4".

Brian
 
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