Depends what spindle you are going to fit. 2.2-3kw water cooled or 10Hp and up using BT holders...

But you have it all wrong there. What would be the biggest longest tool you want to fit and desired deflection. Download HSM adviser it calculates tool deflection nicely.


Cause the tool will be the weak point there.


Also there is very nice stiffness calculator here in the forum. Thats what you need.


Dont worry about the bearings of the spindle, they will take much more than you could push them even routing aluminum.