I'm sorry if this is a little long. I hope this helps someone else.

This is what I've been chasing down for the last day and a half. I never noticed the problem until I had to cut thick object (1 inch) with multiple passes(0.02"/pass). The x axis drifted 3/16" by the time it hit the depth of 1 inch.

You may ask what software are you using, what are my settings, what drive.

Mach3 software settings:
10000 steps, 200 inches/min, accel set to 50,pulse width and duration set to 2.

Gecko 540 drive. (I love the design and packaging)

I started by making sure my z axis move up and down perpendicular to the table. I checked the x and y movement with a dial indicator. I found the y gave consistant reading when I move 3 inches up and back 3 inches. I did not get the same results with the x axis. My readings increase by .003"each time I move it left-right-left.

I then started playing around with software settings. I tried changing the acceleration, pulse width, velocity, backlash. sherline setting. No success.

Change the 6 ft 25 pin cable with a 3 ft cable, moved the power supply away from the cables and Gecko drive. No change.

Then I re-installed Mach3. No change.

I checked my bios settings. All the setting were correct.

I swaped the the x and y cables that connected to the Gecko 540. The problem followed with the x port of the drive. So, that told me my machine is good.

Now is it the PC or drive? I read alot last night about losing step. I thought about getting another graphics card. But, before I go and spend more money on this hobby. I had one last thing to try. Swap the A axis board with the X axis board. Run the part again. It came out perfect!

I'm so glad I purchased the 540. I had a spare drive when I needed it. Now I have to see about relplacing the defective drive board.