Removing collets

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paulinlapine

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I have a new (to me) mini mill that uses MT3 collets. They seem to be quite hard to remove . What I do is to loosen the drawbar a couple turns and give it several hard taps with a hammer. The collets then come loose and I can remove them. The collets are clean and dry, as is the spindle bore. My question is, should I apply a small amount of lube to the collet before using it, or is it best to use it dry and live with the stubborn removal. I only tighten them up to what I would describe as snug, not overly tight.
Thanks in advance
Paul
 
I very lightly lube the inside of the spindle taper and the outside of the collet. The inside of the collet and the tool I insert into it are clean and dry.
 
Also if your not try using a brass hammer ,I just snug in very lightly about a 1/4 of a turn and it works well for me. Rick
 
Any taper less than 7° in considered self locking. Morse tapers are on the order of 3°, so your taper is performing as expected. I was taught to lightly lubricate all tapered items like adapters, collets, mandrels, etc. ....
 
Morse tapers (and B & S 9) have a shallower angle than R8 taper and so will want to stick in the spindle. They can be tightened less than R8 collets and will still grab the tooling well, and will release better. Oil can certainly be used on MT and B & S tapers for easier removal. Some mills have a drawbar that pushes the collet out after loosening it when you continue to unscrew the drawbar. You might be able to find or make something like that.
 
Thanks for the suggestions, I'll try a little light machine oil on them and see how that works.

I'm finding that the more I learn, the less I know. This is simply a hobby for me, but a really fun one.
 
Not light oil please. It will migrate to the inner surfaces that need to stay clean and dry to hold the work. If you don't have grease use a smidgen of butter.

Tormach calls for anti seize.
 

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My mill has a NMTB 30 taper, and it grabs firmly also. I routinely clean the spindle with a felt wipe (ebay special), and wipe the holder with a rag before inserting. Then to remove I do similar to what you described in your post. That is I loosen a few turns then tap a couple to three times with a brass hammer, which then drops the holder. I use the same procedure on my horizontal mill and on a friend BP (R8).
I guess what I am saying is what you described seemed normal to me questioning only the "...several hard raps....".
doug
 
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