From the IH web site:
Our Turnkey 3 axis CNC Mill uses 410 in/oz peak motors on the X and Y axis.
The drive ratio is 4:1. So the ballscrew sees 1640 in/oz of torque.
Our math: 410 in/oz x 4 = 1640 in/oz
The Z-Axis uses a 648 in/oz x 4 = 2592 in/oz
So the 507 in-oz motors from DMM at a 3:1 ratio would give me 1521 in-oz.
With a 5mm (.20") lead screw that equals 3000 rpm / 3 = 1000 rpm.
1000 rpm x .20 = 200ipm rapids.