I use a Baldor 3/4 hp 8" buffing machine for metals/tough plastics like Ultem. I think it runs about 3600 rpm. It will destroy alumilite, celluloid, cellulose acetate, and acrylics. This was not a tool I would have chosen to buy, but my brother had it and gave it to me.
I use a cheap harbor freight 6" buffing machine for mostly acrylic. It runs in the 2000-3000 rpm range I think, and is not an absolute destructive monster like the Baldor is. It requires a light touch with alumilite and cellulose acetate/celluloid, and has the tendency to burn edges like the cap lip or finials.
lastly, I have Beall buffs mounted on a 1/2" threaded rod mounted in my mini metal lathe, which I run anywhere from 1000-2500 rpm, depending on the material. I usually just reserve this for especially delicate or heat-sensitive materials like cellulose acetate or celluloid.