Luckily precision is not the aim here but quantity. The holes have to be on a precise place, could be slightly tapered and sizes could slightly vary. This is not drilling rubies for watches. Just jewelry.


I spoke with my friend and he said 1.2 to 1.5mm holes are ok. So i will forget for holes below 1.2mm. So seems a china spindle with VFD will work right and have acceptable speed. May be even better will be one of the small Dc spindles. The question here is if that should be driven down by motor, lever or just counterbalanced and let its weight drill slowly the stone.