High strangeness with 440

I’m engraving a part that I made. It’s rectangular in shape. I probed a piece of material the same dimensions. Loaded the program and hit cycle start. The engraving was milled in the proper location. I removed the test piece and loaded my part. Probed the part and hit cycle start. There was a slight thump and the engraving started about .250 in -Y.

I don’t know what happened. So I powered everything off and left the shop. I plan on cleaning my probe tomorrow. Also on the list is to look at the Y and X axis ball screws to see if they are dirty or if something is loose. Does anybody have any ideas on what happened? The ways were lubricated and the travel speed was at 25%.

Ball screw coupling could cause a clunk and position off by this much.

That will also be something I will check. Thanks.

Just to report back. I cleaned the probe contacts looked good, but I cleaned them anyway. The ball screw coupling screws were tight. Everything looked clean and lubed under the way covers.