Sizing Clearpath motor

[DrLocke]

I am upgrading my Grizzly 760 mill to CNC. Have Acorn, centroid PC, and CNC12. I am planning on using Clearpath SDSK motors on X,Y, & Z. Have estimated that X & Y should be good with 3432S with its 1400 oz-in with direct connect to lead screw. Little concerned about the Z axis and direct connect with 3441S motor as the 6400 steps per rev with be about 0.0005 inches per step. My concern is the holding torque and possible position hunting resulting in excess variation. I guess I'm asking if I should plan on a 5:1 gearbox to reduce that variation. All assistance appreciated!

[Richards]

I'm wondering what the distance traveled per revolution is on that axis? 0.0005" X 6400 steps per revolution = 3.2 inches per revolution if my math is correct. The Chinese mills that I've owned had 0.2" travel per revolution. I have a 5mm ballscrew attached to a ClearPath RLN motor (800 counts per revolution). That axis moves 0.000246" per pulse. A 6,400 count ClearPath would move that 5mm ballscrew just 0.000031" per pulse and a leadscrew with 0.2" travel per rotation just 0.00003125" per pulse.

[DrLocke]

Z axis is about 3 1/2 inches per rev. X & Y are 0.1 inches per rev.

[DrLocke]

Just ordered a 5:1 gear box from cnc4pc that will bolt between my Z axis and a Clearpath 3432P. Won't need the 3441S with the gear box.