Running the second and third operations on these skateboard parts today!
I had some weird sound issues right out of the gate when roughing out the pocket on the second operation. Had a high pitch hollow sound each time it took a pass; as it turns out, one of the teeth broke off and was dragging along, pushing the aluminum instead of cutting it.
For the finishing passes, I copied over the same toolpath settings I used for the first op and got an excellent surface finish on the bottom and side faces; however, the corners weren't all that great; you could visibly see each stepover the tool took. I've never used the pencil toolpath before, but it seemed to look pretty good in the simulation and was precisely what I was looking for. The pencil follows along the corner intersection of the vertical and horizontal walls cleaning those edges up with a single flowing motion. I am honestly shocked by how good it turned out after I tried it. In the past, I would try and use the trace toolpath and manually draw geometry to have the tool follow along, but this one makes it so much easier.
I also had some difficulties when I put the part on the 4th axis fixture plate. There are two holes on this piece at weird angles, and instead of trying to make some elaborate fixture plates for them on the 3-axis mill, I decided to do it on the 4th axis. For some reason, the tool heights are weirdly and consistently off; I've got each of the tools set right (four inches from the top of the table, in centerline with the a-axis), but they all cut too high. I did deck the surface of the fixture plate to ensure it was at the right height, and I'm almost wondering if maybe I didn't set the endmill correctly on that, and so the plane I cut is lower than it should be.