Calibration Block with Countersunk Hole and Slot

Calibration Block with Countersunk Hole and Slot to catch problems with elements inside perimeter of object.

Instructions

I took the 20mm block from Spacexula's calibration set and added a countersunk screw hole for a M3 socket-head screw, and a slot for a M3 nut to be able to check my bots ability to accuratly do inside holes and slots in an object.

Edit: (from algspd's comments below, I updated the object to use values that should produce a snug fit, the old values were the nominal diameters for an M3 socket-head screw)

The head diameter is 5.89mm and the shaft diameter is 3.06mm, this should produce a snug fit. I created this calibration block to test the accuracy of the inside diameter of a hole on a Printrbot Plus, from a SketchUp file.