I haven't used one of these machines, but I wonder if your collets are
seating properly.
If you start seeing wear marks (changes in the collet surface finish) at the
small end and nowhere else along the collet, the collets or the spindle may
be out of tolerance.

I've never liked rapping on the drawbar to unlock Morse tapers, but it's
been done for decades, so it's an accepted practice, although that practice
did come from machines weighing 1000s of pounds, not light duty benchtop
machines.

When the collets don't seat properly, it may take excessive torque to attain
a good grip on the cutting tool shank. If the morse tapers don't mate nearly
perfectly, some improper wear or distortion is likely to occur.

If you're not able to attain a solid grip on the proper size of cutting
tool, you may be faced with altering the small ends of the collets to reach
the proper gripping force.
If the machine is new, you should probably discuss it with a customer
service technical person for the seller.

A nearly ideal setup might include a lever actuated cam lobe to apply force
to the drawbar end, but this isn't particularly easy to retrofit into an
existing machine design.

Tying to fabricate a big lever-closed clamp-type tool, similar to a engine
head spring compressor doesn't sound like a very easy task either. There
would probably be too much flexing along the length of the tool to create
enough pressure to release the collet.

All that you may be able to do is closely examine the surface finish of the
collets, and feel the inside finish of the spindle with your fingertips to
determine if there are any irregularities.

Another possibility could be mis-marked collets. It's possible that some
collets actual sizes may be incorrectly marked. You could carefully measure
some precision ground parts (unless you have a set of precision plug gages)
to see if other sizes are gripped more securely.

If the proper size isn't being gripped adequately with a reasonable amount
of torque applied (but I don't know what a reasonable amount would be), I'd
think there are likely to be some manufacturing tolerances that were
exceeded (manufacturing defects), either in the spindle or the collets.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


wrote in message
...
It's one of those Micro-Mark mini-mills. I'm tired of beating (albeit
with a plastic head mallet) the bejesus out of the DB to loosen the
tapers due to overtightening. Is there a recommended torque for these
things. Thanks.