3-Axis Calibration

I made this to check whether the X, Y & Z axes on my printer are set-up correctly.

I have made this part with a notch at 50mm on all axes and and an overall length on all axes of 100mm. I figured this would allow me to see if any inaccuracy got worse as the travel increased, i.e, is the %age error at 50mm the same as at 100mm.

I designed it with radii at the edges in a bid to remove any edge bulges from affecting the measurement. I am not sure how successful that was, but it shouldn't affect printing anyway.

When you rotate this in your slicer, make sure you position the Z-axis part of the test in the right direction. You should be able to determine the correct orientation by looking at the photo I have uploaded.
Basically, the Z-axis has two lumps half-way up, rather than one lump that the X & Y axis each have.
I failed to do this, hence why I mention it!

The standard co-ordinate system of my CAD package is obviously out of whack with that used by Thingiverse and I haven