Expanding drum sanding

I could use some help. I am trying to choose between Covington
Expanding Drum Sander, for wet use on enamel with metal. They have a
variable motor speed unit and I am not sure if it is necessary over
the one speed motor. Any advise?

Thank you,
Sharon
Sharon Kaplan Jewelry

Trying to replicate the hand stoning of enamel with a rotary wheel,
on anything other than flat enamel will bring more problems of
keeping it true and level then the time saved in doing it with a
machine. I used a 320 grit vitrified wheel some 8 in in dia by 1in
thick turning at 2 revs a sec.

IE slow!! with water dripping on to the wheel where I was grinding
the enamel.

I used the front of the wheel for bevelling where the edge of the
enamel met the edge of the pendant and the side of the wheel for the
face.

Always a problem holding the work against the side, so I would do
half the face then turn 180 deg and then the other half. then of
course re fire it to gloss the ground surfaces. Also I build all my
own machinery, you will need resolve this issue to do the same.