Hi Dave,
We will need more information if we are going to properly confuse the issue. Where are you located? The answer may depend upon where you are located. What is the pitch of the leadscrew you are driving? There are probably other questions that have escaped what's left of my mind.
Let's assume you have a .100 inch/rev. leadscrew. Further, let us assume that you may wish to run a roughing cut with a 4-flute cutter at 2500 rpm that works out to .005 inch/flute. That says that you need, in the cut at least, 2500 X 4 X .005 = 50 in/min cutting speed (mind you, these "numbers" were pulled out of quality thin air). More to the point, you want to "rapid" from "stop to stop" in (say) 30 seconds. If your "stop to stop" travel is (say) 20 inches then you will want to drive it at 20 / .100 / .5 = 100 rpm.
If I am not mistaken, the motor you have can accept either a PWM or SCR type speed controller. This is not my field, but there used to be relatively inexpensive (SCR) speed controllers that gave you (from memory, mind you) 20% to 150% of rated (rpm) speed for such motors. You would then have to ratio gearing from there.
Does this help?