Hi Rob,

The geometry has certainly needed some adjustments to be made, so more checks are probably not a bad idea. Recently I have been focussing totally on tweaking the squareness of the X and Y axes, but I must confess I haven't done a whole lot over the Z axis beyond proving that the table is level over the working area to a reasonable margin of error. Something else to add to the job list!

That said, I've convinced myself that this isn't the cause of my measurable axis errors currently. I was initially thinking the out of squareness was the only cause of my non-circular circles - but that just "squared up" the axis errors I am now seeing....

Why isn't this more straightforward?!

Cheers
Graeme