Flexible Couplings

thingiverse

Mix and match any combination of these 8 mm and 5 mm diameter couplings. The 5 mm couplings have both round bore and D-shape profiles. Adding a spacer between the couplings increases flexibility. Any type of spacer should work (washers, nuts, standoffs, etc.) I include a spacer with an outside diameter of 36 mm x 2 mm thick. It could be scaled in the Z direction to adjust the thickness. The bolt circle diameter is 24 mm if you want to mate these to one of your own designs. It is designed to use M3 screws. NOTE: The 5 mm diameter couplings without the flat (D-shaped) have a relatively low torque capacity. 10/05/13 UPDATE: Added another coupling. Clamp-style 3/8" diameter (Coupling_Clamp_0375in_Half.stl) Instructions I suggest slicing all threaded parts at 0.1 mm. Non-threaded at 0.15 mm or 0.2 mm. 100% fill. PTFE tape on all threaded parts (see instructions for threaded parts on http://www.thingiverse.com/thing:110593) To make the coupling even more flexible, you could reduce the thickness of the flange. The flange is 1.6 mm thick. I use Cura for my slicer and it has a "Cut off bottom" feature that allows for this. I don't know if other slicers have a similar feature. Reducing the flange thickness by 0.4 mm makes the coupling quick a bit more flexible - although not as strong, obviously. To make the coupling less flexible, do not include a spacer between the flanges. Arrow on nut points toward other coupling (threads are tapered). I will add more detailed instructions later.