I've been using a Foredom #18D (d=duplex) for about 3 years now, and
really like it. I purchased it to do fine detail wax carving, where
I would be holding the handpiece like a pen/pencil, as opposed to the
"overhand" grip I use on my #30 for daily grinding, sanding, etc. I
chose the duplex adapter because it helps the shaft make that tight
90*+ turn as I hold the handpiece at odd angles, and I chose the #18
because is had the smallest diameter body of any of the quick-release
bodies out there.
After using it for the carving jobs, I began to try it for stone
setting. I found that in some cases, the collet would not hold burs
tightly enough to grind seats for pave and flush set stones, but
works really well for channel setting, where being able to hold the
handpiece as described above gives a bit more control.
I have used it so much, that I am currently having it rebuilt, as the
collet finally refused to hold any burs for any job, and the
bearings were screaming at me. The rebuild is about $75, and worth
the expense for this fine tool.