Elastomeric Coupling 0v1: 4.75mm stepper motor to 8mm threaded shaft

thingiverse

This experimental printable elastomeric coupling features a molded and cured-in-place rubber insert of RTV silicone sealer. It's an improved version of http://www.thingiverse.com/thing:7687, offering increased stiffness and self-centering capabilities. The design boasts robust clamping and excellent balance when evenly tightened. A HD macro video showcases the printing process at http://www.youtube.com/watch?v=rkfMtFEaQG4. This coupling is a variation of two existing models: http://www.thingiverse.com/thing:7678 and http://www.thingiverse.com/thing:7687. To print the parts, use a solid profile for strength. Post-printing, drill 3mm holes through the clamping areas. Clamps will exert good force with limited travel. Ensure shaft holes are snug to maintain stability; adjust hole sizes if necessary. To install the RTV silicone sealer, fill three spherical cups and press the top piece in, jiggling for even distribution. Use index notches for alignment. Cure in a warm spot like a heat vent or sunny window sill – curing time may vary from several days to weeks. Excess silicone can be cleaned off by rubbing, followed by cutting the alignment triangles. The coupler should offer flexibility in all directions while maintaining positive rotation and fair stiffness. Alternative materials like two-part silicones or Sho Goo (http://bit.ly/hc11mc) could also be explored for different stiffness levels. Please share your experiences using this design, including the materials and performance outcomes.