Zeroing Tool for CNC

Getting a hobbyist CNC machine to absolute zero in the X and Y axis can be difficult. Simply stick this tool in your spindle (comes with 3mm and 6mm variants, but can be customized in OpenSCAD), use it to set the machine to the exact corner of your work, and then remove it and put in a cutting bit. The center of that bit will be at the exact corner of your workpiece. This tool does not help set the Z axis. Locking the stepper motors while switching this tool for a cutting tool is essential,