I have a watch that the strap buckle pin keeps coming out.
The hole for the pin is slightly too short, not deep enough to seat the
retaining pin properly.
I have a drill bit just under 1mm diameter that would do the job and
allow me to increase the depth on the pin holes by around ½ - 1mm on
either side.
The problem is the drill bit is too small for my me elec drill and my
dremel tool, the chucks wont hold it and it just slides out.
I have checked other bits and bobs but cant find anything that thin to
use as a punch as an alternative. They are either too thick or not
strong enough.

Any suggestions?