For the standard sherline supplied steppers and drive, the MaxVel setting provided by them is 0.4 if you want another point of comparison.
No issues with stalling on x and y at max jog speed and with feed rates of 4~6in/min can do .020" cuts in mild steel with a 3/8 endmill OK (no powerhouse by any stretch though!) Z needs more power for drilling though. That one does stall more often than I'd like!
Check that the gibs are properly adjusted, if they are too tight = too much friction, but too loose = too much slop, especially noticeable on Z when drilling.
