CNC plasma cutter torch effecting steppers or controller

[glasswoodmetal]

I hope I am posting this in the right place.
I built a cnc plasma cutter, and it works reasonably well, except one major problem. When I connect the torch switch to the relay, it works for a few cuts, then the steppers start going backwarwd or lock into one directin only. This also happens sometimes, but not often, even when I use a manual remote switch.
I am using an esab 875 cutter, and a lightobjects controller, with mach3, windows xp.
It also seems that long cuts don't create this problem, it's mostly when I cut a very small line.
I even put a battery powered relay on the relay to isolate the switch from the controller, but it didn't help.
Thanks for any help or suggestions.

Glenn

[jgramlich]

This is just a guess, but check your wiring. It almost sounds like you have a short somewhere or you're getting signal induction from one control wire to the next. Are you using shielded wiring? That *might* help...