6 inch spin on face plates are readily available from most
suppliers and can carry all sorts of abrasives and pads for sanding and polishing. Sanding
is normally done at motor speed, approx 1500 r.p.m. and polishing at half that speed. A
pair of 2,3,4 stepped pulleys mounted as shown will give shaft speeds of 2,800, 1,400 and
700 r.p.m. for a 1,400 r.p.m. motor. I mount a diamond cup wheel on the shaft and run at
double motor speed but it does tend to want to jump off the bench at this speed - a couple
of G clamps solve that. The motor was supposed to be mounted the other way round ie on the
back half of the board but that made things turn the wrong way and I didn't know how to
reverse the direction of the motor then.
The photo speaks for itself, a standard Picador shaft was modified by cutting the correct
thread for the face plates and mounted to a ply base on timber upstands. A plastic bucket
sacrificed itself for a splash shield when polishing and this is held in place to the
shaft support with velcro.
Although the belt on this unit is well away from the hands in normal use common sense
dictates adding a belt guard - make the top hinged so that the belt can be changed easily.