I have a home built CNC. I had a bearing go out on my Y Axis so I replaced it. After doing that I am now getting this Stair Stepping in my cuts on the Y Axis. My gantry is mounted to linear rails with two bearing blocks. When I replaced the one bearing, I didn't remove it from the other bearing mount, so I didn't expect any issues replacing this one bearing.

Thinking that it might have gotten a little off, I re-calibrated the steps via Mach3, but still no change. If I cut a piece of 1/8 MDF 10x10" square, it comes out to be a perfect 10" square, but if I cut something like 3/4 thick MDF, it has this stair stepping.

Any help would be greatly appreciated! I'm pretty new at all this.

Thanks,
Jamie