The motors are standard 200 full steps per revolution.
I think the screws are 5 turns per inch.
On a Boss 4 machine if I recall correctly, the ratio from the motors to the screws is 1:1 but
some later machines were 2:1 ratio.
Your motor drivers will likely be set for microstepping which increases the number of steps
required by the microstepping factor. We would likely recommend 8 for this machine.
All three motors are the same.
The 100 KHz will determine the maximum speed possible but does not affect the counts
per unit of motion calculation. Remember that is thousands of cycle per SECOND and motion is
measured in inches per MINUTE.
For the assumption of 8 micro steps, 200 step motors, 5 TPI screw and 1:1 ratio, you would
need 8000 steps per inch of travel. Given 100,000 times 60 second per minute, the PMDX-424
can produce 6,000,000 steps per minute, resulting in a limit of 750 inches per minute. That
far exceeds the 100 inches per minute that this machine is typically capable of running.