Rigid coupling collet

Couples two shafts rigidly by using a double headed collet with threaded nuts tightening both ends. Pretty simple, printed at 0.2mm height in PETg, 0.4mm nozzle, 25% infill. Had to add a 3mm brim on the collet to improve bed adhesion.

The picture is an earlier (but working) version that is 5mm longer. I reduced the length by 5 mm because it looks like it is plenty to have a very good grip.

Uses the threads.scad library from http://dkprojects.net/openscad-threads/

Can be quite hard to get the threads started, still looking at improving that further.

The second picture is the uploaded version. Works fine, but I broke the collet taking it apart. I need a better way to undo each single nut. Don't try and overtighten it without a matching shaft being gripped in the collet, or the collet segments will snap

Updates

Version 5

Updated the code, moved the parameters to the top for quick editing. Added more control on the taper dimensions and angle. Added optional support material to print the coupler without the need for a brim. Refined the geometry to reduce overhangs and to make starting the threads easier.

Version 4

Split the code to allow for more customization, added thread length parameter and an example of a flanged collet (hole diameter 12mm) for a through wall mount.

Version 3

Same output from the SCAD code, added more parameters to allow fitting larger diameters and choosing wrench size on the collet nut.
Removed from the source a list of update comments that were actually pertinent to the threads library.

Version 2

Changed the taper to make it easier to start the nut on the thread, and added a hole through the middle to use a small Allen key or a screwdriver to help tightening a single side.
The updated version works very well for me, might be a bit too loose of a fit for people with more precise printers. The collet threads are printed slightly undersized and the nut threads oversized so the nut is 0.5mm wider in diameter than the collet. the same goes for the shaft bores, that are 0.2mm larger than the shafts they are meant to fit. It's all adjustable in the SCAD file, though

Category: 3D Printer Parts