I recently installed Mach3 on a Dell Pentium 4 machine with Windows XP SP3 and have been having problems ever since.

When a series circles, squares and letters are cut, they are located incorrectly. It doesn't appear to be skipping steps because the machine cuts some of the patterns in the correct positon but others not. It also returns to the original zero when the program is complete. If the machine skipped steps, the machine would not return to the original zero (0,0,0).

Also, for example, when I position the machine over a 1/8" cut circle on the part, I can see on the Mach3 screen that the curser is off by nearly 1/4" compared to the actual cut part. And yet the zero position is correct.

I've tried the same program on a duplicate Pentium 4 machine with a fresh install of Mach3 and am having the same problem.

I've run these same gcode programs successfully and consistently on my first pc but when I switched to the Pentium 4 machines, the problem started.

It seems to be some sort of mathematical floating point problem but a simple floating point test shows not the case.

Anyone have any ideas?

Just a shot in the dark but I would be inclined to thoroughly check for a mechanical fault in the machine - the problem of loose grub screws comes up quite a lot also flexible couplings slipping etc. etc.

Tweakie.