Well, the speed is an issue, but because the steppers are internally geared at a 1:64 ratio the torque is not really an issue per se. If I switch them over to a direct drive to the screw standard stepper, I would need to use something with appreciably more ungeared torque.
Having to deal with a furnace issue, so not had a chance to measure the actual rate of travel, but suffice to say that it is in the one to two inches per MINUTE range.. But since it's a gear reduced motor feeding that 20 TPI, the torque is plenty to effectively rip the assembly apart if you ignore position and start backfeeding the screw against the limits of the slides. Limit switches are needed.. If it can break two ton bind epoxy, I think it may be okay for wood routing.
Dealing with a furnace failure at the moment.. The one device in the uinverse that gives me the heebie jeebies.