Ultimately I've taken my KMB1 back to its original (more or less) retrofit state. I'd greatly benefit from a faster spindle. Of course I can slap a companion spindle on it, but that's not a real answer. I've got three small Speedmaster mills with 24K spindles for the majority of my high speed machining. I'd just like to bump the spindle speed on the Hurco up a bit. Its fine when I am roughing steel, but most of the time I am cutting aluminum. 3600rpm is like riding a snail. I think the spindle could take a lot more, but I'm not so sure about the motor. Its got an old Leland 5HP 4 pole motor and the mill manual derates it to 4HP. Seems reasonable. Its running a 3.7kw spindle off single phase, and I just set all my calculations to a max of 3HP. Really though I rarely break one horsepower except on those rare occasions when I actually am roughing steel stock. I'd really benefit from getting it up to 5000-6000 rpm. In many cases my lowly Tormach 1100 will outproduce the KMB1 because the Tormach has a 5000+ rpm spindle even if it doesn't accelerate as fast or have as big of a spindle motor.

Anyway, I think the New Departure and Fafnir bearings in the KMB1 spindle could handle more RPM.
( I put new (old stock) bearings in it a while back )
I'm just not sure the motor could. I'm putting 120hz to the motor now to get 3600 RPM. The motor is connected to the quill with a 1:1 timing pulley setup.

Similar Threads: