Thread: Selecting a small Mill / Mill/Drill

Originally Posted by rusty steel

I have used R8 and MT4 machines and I can't see where the R8 is better.

Tooling availability & price. If you make everything yourself then MT4 is probably a more rigid tool holding taper than R8. If you buy tooling, I can buy a R8 shank going to a 22mm dia straight shank with drive dogs to take a face mill for cheap, ditto for 25mm and 27mm tooling. Means I can swap face mills between machines easily. I've never seen these tool holders for MT4 (doesn't mean they don't exist of course). I must say that if I were to swing a multi-toothed TCT face mill much over 50mm diameter I'd rather an MT4 spindle than R8 as you're pushing the work holding ability of the taper if you're loading the teeth as you should so they don't rub.

I'm not very enthusiastic about R8, BTW, just I think it's better than MT for most purposes. I'd rather an ISO 30 or 40 spindle & tooling any day. Fast tool changes, positive drive not dependent on friction and repeatability when swapping tooling multiple times over, something you'll never get with MT or R8 tooling.

We all get what we can within our money/size/weight/power constraints.

PDW