Fingers crossed it'll cut ally

[Jonathan]

Yes it's the motor you're thinking of! It's currently in pieces since I'm altering the wiring so that I can change it between star/delta for higher torque/rpm etc. You may mant to consider this for your motors? Easier to swap a few wires than change the motor, perhaps.
I've found the straight collet holder - that looks ideal (thanks!), except the shaft is a bit short! I'd prefer ER25 though since I've just bought a set of ER25 collets for my milling machine. I'll have a look around for one / make one if necessary.

The bearings in the motor are already pretty huge. The one at the 'back' is a large thin section bearing about 65mm diameter if I recall correctly.

Maybe create a thread about using these motors?