improved stepper coupler ziptieless

thingiverse

The origin of this design is to create a coupling for step motors and threaded rods that have the advantages of a commercial -unbalanced coupling-, without having to spend money. I had been using with success "crystal tube" of 9mm exterior, 5 interior, tied up with zipties, but the difficulty of tightening the ziptie securely to the axis/rod and preventing it from moving was an inconvenience. Basically, you need 35 mm of crystal tube of 9 mm exterior x 5 mm interior, two printed prisoners, 2 M3x15 screws with their corresponding nut. The way to install it is to put the crystal tube on the threaded rod until halfway, place the prisoners, and then insert the other half into the step motor axis. The trick is that the step motor axis must make contact with the threaded rod, in that position the prisoners are secured, trying to leave as little gap as possible between them (0.5 mm or less). In this way, an efficient and affordable coupling is obtained. The source file is provided in openscad, which is parametrizable.