This is going to sound weird but i will ask...

what makes a machine capable of cutting at high speeds (besides pure godliness) like the HAAS VF-4ss able to cut at 833 IPM.

is it spindle speed?
more torque in the driving motors?
higher hp on the spindle motor?

the reason i ask i am working on plans to build a mill from scratch so i want to know what i should be looking at to get higher IPM.

NOTE: i am not trying for 833IPM that is just a example.... i am looking at more like 100-125ipm.

Thanks
Mike