25mm penny & arch calibration cube

As an exercise on learning SCAD and wanting a quick way to check my printer settings easily, I created this test object.

The cube is 25mm on a side and contains two circular indentations which snugly fit a penny (n.b. both US and Canadian pennies have the same diameter). One indentation is on the top and is labeled with at T. The other indentation is not the side and has an inset cone.

The two circular indentations allow quick visual verification that all 3 axes are equally well calibrated. That is, if you insert a penny in both indentations and you have more than 0.5mm clearance in any direction, you can tell which one of your axes is off relative to the others. You only need to bring out the callipers if you want to know how much adjustment to make.

The cone serves two purposes - it tests that your printer's filament settings are handling an arch well and it reduces print time, since most of the cube is empty space.