Maximum Bridgeport RPM

[Arkie]

I have a belt drive later model Bridgeport. I'm cutting walnut with router bits on it. Reason being it has a DRO and for the stopped cuts I'm making it works great. I would like to run a bit faster. Top speed right now is 2,720 rpm. Its 3-phase and if I put it on a VFD I could double the rpm, but I don't want to do it if detrimental to the motor or machine.

I don't know the history of the machine but it seems to be in really good condition.

 

[JimDawson]

The motor should take 3600 rpm OK, just watch the motor current draw. You might want to oversize the VFD by 1 HP or so. That will give you 5200 RPM at the spindle at 120 Hz. The bearings should be fine, just make sure they don't get too hot at that speed. I ran my Bridgeport clone at that speed quite often. Make sure the quill feed is not engaged at that speed.

Another option would be to build a bracket to attach a good router to the quill, that way you can get the speed up higher. There is a lot of info on the internet on doing that.