Yup, that worked fine for sending the file, thanks.

By doing the Construct > Curve > Isect test it looks like it's getting confused about some areas where some edges in the knurls just barely graze over the cutting surface, making the intersection more complex.

Here's one such area:



And here's an area where it did not generate one little piece across a part of a knurl, probably because the area traversed is so close to the fitting tolerance:




This kind of intersection through a tremendous number of separate tiny little pieces is a quite complex calculation and things involving little tiny distances close to the fitting tolerance or just barely grazing and coincident pieces will cause difficulties.

Probably the first thing is to scale up by first 10 times or 100 times in size and see if that makes things better, that can help to avoid having little tiny intersections that don't get processed since the area traversed by them is already under the fitting tolerance.

If you still have problems you would then probably want to go along the intersection curves generated by Construct > Curve > Isect and select any faces that are around a problematic area like the ones that I show above and separate those out from the main object, then trim the main object and do some more custom individual work on the pieces that had difficulties.

- Michael