Tiny Single Lever Morse Key (made from 9mm utility knife blade)

thingiverse

This is a tiny but very precise single lever morse key made from a 9mm wide utility knife blade (the ones you can break appart) I printed it from carbon fiber filled pla filament but any other pla will work as well. Besides the printed parts you will need 2 x brass screws M3x10 4 x set screws m3x3 1 cord with 3.5 stereo plug cord OD preferably ~3mm 1 utility knife blade 9mm wide While printing, I broke the blade in two halves and ground the cutting edge dull. I also ground the points on both ends flat so that the blade is rectangular. I removed the outer insulation on ~3cm length from the cable and about 8mm from the leads inside. I then tinned the very ends of the leads using a soldering iron. After Printing, I drilled out all holes except for cable hole on the backside, with a 2.5mm drill bit. The cable hole, I drilled out with a 3.5mm drill. I then tapped all the 2.5mm holes with an M3 tab. I pushed one end of the ground utility knife plate into the knob (a little help with the thumb detector, aka hammer, helped. I then stuck the the cable trough the hole on the back of the base till the leads came out inside. I secured the cable with a setscrew from underneath the base. I then stuck the soldered shilding wire of the cable through the hole inside, parallel to the slot for the knife blade. I inserted the m3x10 brass screws from outside through the holes on the sidewalls and position the set screws in the holes on the top, not tightening them, yet. I put the wire connected to the plugs tip in the hole above the brass screw on the right side and the wire connected to the 1st ring of the plug in the hole over the left brass screw. I then secured the wired tightening down the set screws on the top side of the base. Next I put the knife blade in the slot on the base and inserted a set screw on the bases side to secure the knife blade and its connection to the cable shielding wire. I then loosened the two top screws a little bit and adjusted the two brass screws to the desired play of the key. After that I retightened the top side set screws. This key is very small and light weight, making it perfect for portable operation. You might want to bolt it down onto something (your rig, a leg strap, clipboard). For shack use, I bolt it onto a heavy base to hold it steady on the table. As always, the FreeCAD file is included for you to play with and to make it fully open source.