[laminated]

I was curious if anyone has tried to use the 3 hp 6,000 RPM spindle motor from automation technology on a similar Mill? I recall someone doing this on a Grizzly rf45 clone. But don't remember if they swapped out the bearings. Does anyone know what kind of bearings are in the pm-940m? I can only assume that the spindle hasn't been dynamically balanced to that range since the machine is a stock 3,000 RPM.

[arizonavideo]

The 940M has Tapered roller bearings. After break in and with good grease and proper preload they are good to 4 to 5K RPM.

I have not dome a belt drive for my 940 yet but I have found the gear box to be really quiet for gears. I have run the stock motor to 120 HZ sand it was not too bad as far as noise. A quick fix would me a 3600 RPM D90 face motor and lighter oil and a cheep VFD.

You should be able to run 4K and be fine.

I will make a few belt drive for the 940 this year.

http://i1294.photobucket.com/albums/...102a3.jpg.html