In this final part on the construction of the PCB drilling machine, all its functions are tested and the machine is calibrated. The machine is then ready for its first job.By the time you read this, the first PCB drilling machines have already been delivered — and perhaps also assembled. It is therefore high time that our description of the machine be completed. All that remains is the calibration of the machine. The machine must be calibrated before the driver software is able to determine the reference point, calculate drilling coordinates correctly, position the arm(s) and turntable and raise and lower the drilling head. A number of position sensing switches play a key role in initialising the machine. In this final part we describe a complete calibration procedure for the arms and turntable with the aid of the TanBoTest software, and the use of the TanBoDrive driver software for drilling PCBs. Please note that the German working title of the project, 'Tanbo' (for Tangential Bohrer) is retained in the names of the files and programs developed for the project.