Well the main problem is that the cutting surface in some areas swoops right along hugging some edges of the knurls - that confuses the intersection process, it can get stuff like an intersection for both that overlapping edge as well as some pieces from the surface/surface intersection as well.

Probably the best way to get a result would be to generate intersection curves and then select the intersection results individually and look near the ends - there will be things like additional intersection results overlapping the end (in areas where edges skimmed close to the cutting surface), and some of those will need to be deleted. Once you get the curve to be one single long closed curve then use the curve as the cutting object in the Trim.

Before doing any of that I'd probably scale everything up by 10 or 100 times, and get the seam area joined up by doing that separate one piece and rejoin step.


The basic problem though is areas where edges of the knurl happen do not cleanly intersect the cutting surface but instead skim over it for some amount of overlapping. That type of situation confuses the intersection mechanism. Maybe in the future I can experiment with a mode that will suppress generating intersection results along edges instead of only between surfaces, but certainly in other situations that would cause other problems.

- Michael