Hi.

I am new to mach, and am trying to get my motors tuned.
They sound good and run very well, but the scale is wrong.
The steppermotor turns 1.8 degrees per step, that is 200 steps per rev. My driverboard is set to half step, so that is 400steps.
1 rev is moving my gantry 1mm. I have set mach to mm, not inches.
But if I draw a 5cm line and get's mach to cut it, it's absolutely not 5cm. To get a line of approx. 5cm i have to set the steps/mm to 13!

I just don't get it... So if any one do, please reply! 

If one rev of the motor moves 1mm then the only thing that could be wrong is you have the axis scaled.
Hood

Scale? Where can i scale the axis? It is my first install of mach 3.
I also thought it was some kind of scaling that was wrong, but I just can't find a menu where i can set one, other than the motor tuning menu.
And it should be set to 400 steps/mm as i wrote earlier, but I have to set it to 13 steps/mm just to get close.

In the G-code it says that X goes from 0 to 50.

Scaling is set at the side of each axis DRO, so set to 1 if it is not.
If that is not the problem then do a few tests.
Put 400 into the Steps per unit then save the axis settings. Next zer the X DRO and then on MDI page command a G0X50 and press Enter on your keyboard and see how far it moves.
Do you have any gearing between the motor and the screw? If one rev of the motor means you only move 1mm then you have a very fine pitch on your leadscrew which is unusual, normally 5mm or more would be expected.

Hood

No i don't have any gearring, just fine pitch...
There wasn't any scaling, but when i tried again today it just worked perfect!
Guess the computer just needed to reboot..

Thanks for the replies Hood!

Probably needed the restart to set the motor tuning numbers correctly
Hood