Hello Janet, I use the 2mm diameter flex-shaft polishing pins from
Rio (p.393 in the 2004 Tools and Equipment catalogue) for finishing
hard-to-access tiny spaces. I have a mandrel for each abrasive grade
so that I don't have to fiddle with changing pins. The pins may be
easily shaped by running the tips against abrasive paper. I
especially like them for polishing chasing tools or the depressions
of beading tools.
The only time I've had trouble with the mandrel's collet not holding
the pins in has been when more than about 5mm of the polishing pin
protrudes from the collet after it has been tightened down. Unless
you've been leaving too much of the polishing pin exposed, you may
have gotten a defective collet/mandrel with your kit. If you did have
the bad luck to receive a "lemon" collet with your kit, I have found
Rio Grande to be very good about refunds or replacements.
Anne M. Kelly