I have a servo motor that puts out 900 ppr. This motor goes through a 4:1 gear down to a 10 tpi screw to drive my Z axis. When used with Mach3, I find that I need to drive the motor at 144000 / inch for things to be scaled correctly. This is way too high. Can I use the "Step Multiplier (M)" setting in UHU to correct this?
Short answer - Yes, that is what it's there for. But you will be limited in the speed you can reach before the UHU starts loosing track of the encoder. The manual states at least 150kHz but I've found mine to gets confused abouve 130kHz. 130kHz in your case means 2166rpm/4/10=55IPM.