A morse code practice key. Only 4 parts and simple to assemble. This morse key has been designed using OpenScad. OpenScad is a free 3D design application for most operating systems including Linux and Windows. It is particularly useful to be able to inspect the source code here to learn how easy OpenScad can be. If you wish to simply build the key, just use the STL files. Note that you may need to rotate them so that they lie flat on your printer without any overhangs. You will also need a biro spring, some M3 screws and nuts and one M5 bolt and nut. Assembly should be obvious from the photos. The rear screw adjusts the contact clearance. The middle screw adjusts the sprint tension. Connect thin multi-core wire to the contact screws at the front. Mount the assembly on a suitable wooden base. Do not use this key to switch high voltages. Ideally this key is designed for use with a practice oscillator made from a suitable circuit and speaker such as a 555 timer, astable or other oscillator running from a low voltage battery.