Watch makers screw bit handle 2.0

The best screw driver is the one you have when you need it and the one that fits the job. This design aims to close the gap between these too little watch makers screw drivers that we typically do not have multiple times, and the too big, strong screw bit handles that have no free wheeling end.

Thanks to the imprinted spring that presses against one edge of the bit, your bit should be held securely in place even after some wear out of the handle.

Print as many as you can, ideally in well visible colors and put them in all you hobbyist boxes together with one of the hundreds of bits that you probably have lying around. My orange one will go into the box of one of my model airplanes, that needs exactly this size of screw driver for assembly and disassembly at the model airfield.

Print instructions

Print all parts in the uploaded orientation with 100% infill. There are no supports needed. I recommend PETG, because it keeps its flexibility over time, which does help to keep the spring mechanism strong. PLA is also tested successfully, but I would bet the spring becomes weaker over time if you have it loaded with an inserted bit all the time.

Use a M3 screw with a round head (the length of the screw is not critical at all, any length between 10mm and 50mm will work, I recommend a M3x10 if you have) to mount the distance ring and the free wheeling ring onto the end of the handle. If you use a Prusa printer, you should have a few spare M3 screws in your boxes.

Ideally you should use a thread cutter first, to cut a M3 thread into the handle. But if you warm up the screw a bit with a hair dryer, you can simply force it in.

You are good to go, happy working!