I have a really weird problem, i'll do my best to explain it.
I am cutting 4 pocket holes about 2 inches by 3 inches in a 1 x 8 x 24" board. I have the 4 pocket holes going all the way through the board. I have a 1/2 inch piece of particle board below the pine board so I don't cut into my bed.
What happens is all 4 holes cut through for the most part but one one of them without even touching any wood the z axis will stutter or jump and the z depth will be off about 20 - 25 mm from what I can tell. The cuts after the 4 pocket holes then don't cut get cut at all. I can watch it happen and almost predict when it happens, as it seems like in most cases it happens on the same hole which makes it even odder.
I could understand if there was pressure somewhere that would force that to happen, but I just can't seem to figure out what it could be.
A few things about my setup:
My Z belt is tight, and was one of the first things I checked.
I am using an end mill bit that has most of the shaft in my dewalt router, the depth does not seem to be the problem though as I can cut way past the position of when it hangs on me.
I have tried not cutting all the way through and I get the same problem, as well as slowing down the all the speeds, and it still happens some of the times.
Is there anything obvious I am missing? I may even try to catch it on video so I can figure this out.