It depends on your machine.
The motors are 200 steps per 1 revolution.
Are you using microstepping? I'm not familiar with the keling drives. For argument lets say they are using 1/8 microstep. That means that you have 200*8 steps per 1 motor revolution. So 1600 steps per revolution. Are you using acme screws? What is the lead? I'll guess its 5 TPI. That means you need 5 turns per inch. If your motor is coupled directly to the screw, you will need 5*1600 steps to get 5 motor revolutions which is one inch. So 8000 steps per inch. Obviously you can substitute the correct numbers for your setup and calculate the steps per inch yourself.
Post up some details of your machine if you need more help.