This is an almost completely printable four-threaded fringe twister with a gear ratio of 1:2 (rpm in:out). The largest part fits on a 120x120mm print bed.
I tried printing the clamps at first, but they where too weak, so you can either try to design your own or you can use crocodile clamps (alligator clips?.. Krokodilklemmen in German ;-) .
To attach those, you have multiple options:
- glue them into the gear_small_w_hole.stl with epoxy or similar gluey stuff
- heat them up and melt them into the gear_small.stl (high infill) <- my method of choice
- design your own clamp/adaptor and combine it with small_gear.stl in your favorite cad software. The diameter of the gear shaft is 10.0mm.
I think the rest of the assembly is self explanatory.
Avoid blobs at all costs - especially at the gears. So turn on (agressive) coasting, keep it slow and the layer hight low (0.1, 0.15 for the impatient), unless you are 100% confident your printer can handle it.
You obviously need four of either the gear_small.stl or the gear_small_w_hole.stl (see summary above). Even if you only need a two-threaded twister I advise you to use four gears for better stability of the assembly.
I used Autocad Inventor (free for students) to design this thing. If you need to change something, I will provide you with the source files, if you promise not to run off with them, file patent and make big money (unless you share :-P). Just send me a message or leave a comment. If you only need small adjustments like more/less clearance, I can do it for you.
The whole thing is designed to fit a 120x120mm print bed. The base.stl has to be angled diagonally to fit. If you find the base handle to be too small, you can design your own. I included a technical drawing of the base part with hopefully all the needed measurements. Also if you ask nicely, maybe I'll consider designing a bigger one myself ;-)