Okay I have been doing some math with calculations from Roton and others to try and come up with screw sizing for my table. I have about a 35lb gantry head a 1HP(.73Kw) servo motor that has a continuious stall torque of 158Nm (14lb/in) max speed 5000rpm.

I plan on stepping the motor down 2:1 with a belt and driving a acme screw. When I use there formula for calculating force for acceleration I come up with .38lbs force (using 35lbs * 42 ft/min / 3860). The 3860 comes from 1930 * 2 seconds.

This seams low. That means I can accelerate a 35lb load to 42fpm in 2 seconds using .38lbs force. If this is the case what thread would be recomended for this application? The head is running on 2 THK rails with 4 bearing blocks (I know, over kill)