Help needed

[Neale]

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.

Isn't this just a question of wording? A misaligned Z axis will not cut square and will need tramming. When I say "misaligned", I mean not moving exactly vertically in either the left/right plane or the front/back plane, and it will probably need adjusting ("tramming", to use the jargon) in both.

The ripples show up better with a large diameter cutter (I have a 50mm mainly for this purpose), and with the minimum of overlap between adjacent cuts. Do a few runs both along the X axis and the Y axis to see the misalignment, if any, in each of the axes. My guess is that there will be some kind of "slacken the bolts and tap it sideways" adjustment for left/right errors but likely to need shimming for front/back errors. i won't talk about X and Y in this context as different people use these terms differently for along/across the bed.

There are other interpretations of "misaligned" including the leadscrew not being parallel to the guide rails or the guide rails not parallel to each other but these are more concerned with freedom of movement of the axis and need sorting before being able to check accuracy.