Quote Originally Posted by AndyUK View Post
Can we deviate slightly from topic and discuss this? As a rather inexperienced user, I'd have thought that ripples here would indicate that the spindle isn't trammed - I wouldn't have thought a misaligned Z axis will show when the cut is at a constant Z.
If the cutter face isn't square to the bed, when you cut it will do an angled cut. The larger diameter cutter you use, the more the effect. This will make a sawtooth wave ripple on the bed and it is quite noticeable. the distance between the ridges will depend on stepover. I am assuming that you use a raster or spiral pattern, trochoidal will be less noticeable.

This error will also be noticed on the side walls of a deep cut.