Your steps per unit are determined by your motors, any reduction you have beteen the motors and ballscrew/leadscrew, the pitch of the ballscrew/leadscrew and finally if your drives are microstepping.

For example, say you had 0.2 inch pitch screws, normal 1.8 degree (200 steps per rev) stepper motors, 2:1 reduction and 10 microstep drives it would be as follows.
 Amount of steps to turn the motor 1 rev is 200
Amount of microsteps is 10 so that means the drive needs 2000 steps to rotate the motor one revolution.
 You have 2:1 gearing so it takes two revs of the motor to turn the screw one revolution so that means 2000 steps x 2 =4000 steps to turn the screw one rev.
 Finally your screw is 0.2 pitch or 5tpi so it takes 5 revolutions of the screw to move 1 inch (which is one Unit to Mach) so 5 x 4000 = 20,000 steps per unit.

If your machine is moving one inch when you tell it to move one inch then the steps per unit you have set will be correct.
Hood

Yes my machine does move exactly 1 inch when requested. I simply downloaded a file that automatically took care of the machine setup so I really do not know much about that as you can tell I'm sure.

The only question I have now, is after I touch off and make my DRO corrections for X and Y and Z.  Should I go to X and Y zero before clicking Cycle Start or does it matter if I Cycle Start at .0005 or .005 or 5.0 or some other number off of X and Y Zero.

I guess I was concerend that the machine was not moving back to exactly Zero and that made me wonder if I would have an accuracy problem.

Thanks,
Bill

You will only  have accuracy probl;ems if you are needing accuracy of better than 0.0014inch and the only way to improve that would be to alter the gearing  etc.
As it is a router then being within 0.0014 will likely be more than you will ever need so no worries
 If it was a metal working machine then you would want better resolution.

To answer your other question, no you dont need to go to zero as you have told Mach where the tool is at that point in time so when you start Mach will just take it to the first point in your code (or as near as it can) and then carry on withthe rest of the code.

Hood

Thanks Hood for working through my concerns. I was kind of guessing that since I had told the machine where it was after each touch off that it would know where to go but I wanted to confirm this. I was also wondering if I had made a mistake in techinque for touch off but I feel confident now. I will use the machine for wood working and from what you explained it sounds like I will have excellent accuracy. I did cut one precise part using machinable wax and it came out right.  My machine is a Romaxx HS-1.

Thank You,
Bill

No probs Bill and wood probably moves ten times the ammount of your resolution just by heating it with your breath so dont worry

Hood