Missing steps! Upgraded my screw drive to R&P

[watsonstudios]

I just upgraded my router to a 5x10' R&P drive and now I seem to be having accuracy issues. I've been playing with the settings in Mach, slowing velocity & acceleration and also bumping up step & direction pulse width but I can't seem to get my accuracy back. I think I'm missing steps but I have no idea where.

I'm basically cutting 4 parallel lines that are 4 inches apart. I'm getting inconsistency whether I cut them in X or in Y. I've attached a quick diagram of what is happening.

The blue lines are what it's supposed to look like and the red lines are what I'm getting. You can see how it's almost random where the errors lie. 2 or 3 lines can be right on and then one may be slightly off. Any ideas about what could be going wrong? Everything worked great on my smaller, screw drive router and accuracy was fine.

Also what is happening is when I cut out a profile, the position where the bit is on the exit cut is slightly off from the position of the entry or start of the cut. This is telling me that steps are being lost in the process of cutting the profile and not ending up where it started.

Any thoughts would be greatly appreciated. Thanks,
Jon

[tulsaturbo]

I would first check the pinion gears if you have not done so already. They may have come loose on the shaft of your stepper motor or gear reduction drive.

[watsonstudios]

Thanks, but no, I already checked all the pulleys. The set screws are in the flats of the shafts so slippage is unlikely. I think I would get much larger errors or inconsistencies in the measurements if the pulleys were loose, especially in the X or A axis, I would get major racking happening since they are slaved. Somewhere I'm losing just a few steps and it seems to be happening at random.