Set screws don't bite well on the hard HSS inserted bits, so they
sometimes slip enough for vibration to loosen the set screw. You might
want to roughen or grind a tiny slot down the 'set screw side' of the
bit.

Slower to remove/replace and perhaps less secure, but CA glue can be
used to fix the inserted bit. Again, roughen the bit for a better bite.
There may be better adhesives.

You might want to try having the set screw on the under side of the
shaft. I think it may help to keep dust/crud from packing into the hole
for the hex wrench.

A short, 4 or 5 in. piece of aluminum or steel bar, bolt or whatever,
maybe 7/16" or so, that duplicates the bit's hole and set screw's
threaded hole makes a handy holder for sharpening the bits.


Turn to Safety, Arch
Fortiter



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