Help with motor tuning

[precisionhone]

Hi everybody. I am new to the CNC. I have purchased a sherline CNC mill. I have download mach3 but it will not reset so I can use the prograam. So I downloaded mach2. It works fine. But tuning the motors seems good. I move it .100 and it moves .100 with the indicator. But when I go and run the program. It doesn't move the same eveytime. I have the X moving 2.5" after it drills the first hole and moves to the net locaation. Some times it is short about .100- .150 and times it is long +.100 to +.150 and sometimes it hits right on. Also the Z seems to get shorter with each hole it drills. I am not sure it is missing a step or I don't have the motors tuned right. Please help. I would appreciate it.
Thanks

[ger21]

Most likely missing steps. Lower the accel and velocities by half.

To get Mach3 working, try toggling the active low setting on the estop pin in ports and pins, input pins.

[CurtisBarclay]

I have a similar problem, I set up Mach 3 in Windows 7 and I can't tune the motors using the Motor Tuning and Setup dialog, The motors do nothing when I move the Velocity slider as described in the Video tutorial.
The motors won't turn until I manually input the Velocity and Acceleration.

How can I fix this problem.

[ger21]

You use the up and down arrow keys to run the motors while in the motor tuning screen.

[CurtisBarclay]

You use the up and down arrow keys to run the motors while in the motor tuning screen.

The simplest answers can make you look foolish!!

It works!

Thank you