Steps per inch depends on what motors (and encoders if servos),drives, screws, and gearing. You can use any screws you like. Most stepper motors are 200 steps per revolution. If you use a Gecko 10 microstep drive, that gives you 2000 steps per revolution. If you use a 5 turn per inch screw, the you have 2000 x 5 = 10,000 steps per inch. If you use a 2 turn per inch screw you'd have 2000 x 2 = 4,000 steps per inch. You then tell the control software how many steps it takes to move YOUR setup 1 inch.