Thanks mate but its more a geared motor question than a VSD question. I have plenty of motors around both 1 and 3 phase but they are all either 1450 or 2900rpm and I want a geared one to somewhere between 150 - 500rpm that I can them put on a VSD. I haven't heard great things about the single phase VSD's so I want a 3 phase. Also I have a few 3 phase VSD's on hand ready to go.
My other option is looking for a worm drive as used on most conveyor systems but they all seem to be geared really low. I have one on my current mill and even when running that at 120hz it takes 30 mins to mill 5kg as it's so slow. I want to be able to mill 100kg or so in 30 minutes.