manual mill converted to cnc

OK guys I need some advice.
I converted a manual mill to cnc and I was running a program the other day and in the middle of program the x axis stalled fortunately it was in between holes so no damage was done, so I reset the part started again and everything went just fine. I started part 2 and the same thing I had run the program twice.

The machine is a Jet jmd-15. I'm using 570 once inch stepper motors with 3 to 1 belt drive the stepper drivers are set to micro step level one (200 steps per rev) a total of 6000 steps per inch, 3 amps motor current , half current at idle.

What could cause it to stall in the middle of the program one time but not the another?

Thanks
Orson

The program continued to run and the axis stopped moving. I immediately stopped the machine and was able to jog back to point were the problem started and jog back and forth with no problems and then jog back to 0 and then restart the program.

Orson

I'll check the mechanical parts. Any idea what electrical problems would cause this?

I had the acme screw nuts to tight and causing a ton of resistance so loosened them up and it looks like it will run pretty good now, I guess I'm going to have to live with some back lash.

Thanks for the help.

Are you running a Mesa card or the Parallel Port?

I'm using a parallel port for now but I would like to use a mesa card when I can afford it.

Having been a Mach 3 user for years via PP (I have used USB and Ethernet SmoothSteppers too) . I am now trying to understand LinuxCnc and its pros and cons.

What I have noticed is that LCNC and Mach are sensitive to the computer itself. Mach calls it a driver test. LCNC a maximum jitter. They might be one and the same I dont know. I do know I have run Mach on many different PC's and experienced different results. Some set ups were capable of high rapids, some stalled at random times. I never could trace the issue but the PC's had very similar specs generally.

That was why I asked about the parallel port. After looking thru the forums, it appears LCNC might not be trouble free either.