Had a go using motorcalc sheet but does not look right.

[Robin Hewitt]

I think you meant 1.5m/s cutting speed, but what I was looking for was the acceleration you are using with that.

That was cutting speed.

There has to be a top speed where it is okay to slam it in to reverse without losing steps.

No point applying accelerations below that speed so I don't. The 1.5mm/s feed has no accelerations.

Incidentally, slowing the axes down to maintain feed rate for arcs and slopes is easy. I started out playing gradients but it's not necessary. Took a while for the penny to drop.

At the sharp end of the program, you eventually step X, Y, neither or 'X and Y'.

If 'X and Y' you increase the delay before the next step by root 2.

Simples :naughty: