Hello all! I've had my 1994 Shoptask 17-20 XMTC (the white one) for many years. I've upgraded a bit (Gecko540, Mach3, VFD motors, etc) and used it primarily as a CNC lathe with TECO L510 VFD and .75HP motor.
More recently I decided to get the mill working and I have spindle related questions.

On the mill side, I installed an identical TECO L510 VFD and a .75HP motor @ 1780RPM. This puts the spindle at about 2800rpm on my handheld tach.

I'm used to milling aluminum at +5000rpm on a different machine (Tormach 1100PCNC) and am curious if the Shoptask spindle is safe to run above the 3000rpm mark. These are essentially tapered trailer bearings, so I'm not sure what they would be rated for.
If I'm limited to 2800rpm, do you normally just adjust F&S with 2800rpm limit or are there any tricks for milling AL at slower RPM? More or less flutes? AL specific tooling?

I'll post some photos if there's interest. I don't think it's too much more modded than the next guy's though.

Thanks.
-Rich