I don't think it's a hardware problem

OT-CNC, immense thanks. G64 at 0.001 helped a lot. I've improved the carve a fair bit during the past month, but this takes things the last (large) step. I started trying to carve a topo, it looked awful with machine marks.

scotth, thanks for explaining Axis details to me. I will look at what you found.

tommylight, may we hear your idea anyway? I'm just carving a test pattern now, there may be other issues lurking. They usually travel in packs.

The picture didn't post for G64 0.001, I forgot to resize it. Here it is.

Looks much better now.

I'm glad that was an easy fix.