Printable Parametric Heim Joint/Rod End Bearing
by UechiMike, published
I put this together as an exercise to see how feasible it was to print a heim joint that actually works fairly smoothly. I plan on using this for a rocker-bogie style printable suspension.
I was pleasantly surprised that after printing with some pretty close tolerances and some very light sanding to the center piece that the joint operated very smoothly.
I tried to make the scad as parametric as I needed it to be but it works fairly well. I've tried printing it in one size and assembling it and am very happy with the results.
The total cost of this joint is around $0.40 for screws/hardware plus ~2.5 meters of plastic. Far cheaper and lighter than a metal Heim joint.
Use the provided STL (23mm diameter ball swivel with a 3mm opening for attaching hardware. Uses 3 M3x10 screws to hold the halves together. Alternatively modify the scad file as necessary and generate STL.
1) Print (thinner layers = better for smoothness of joint. I printed 2 shells 0.3 mm Layer height and 25% infill)
2) gently (and I mean gently) sand the ball swivel - mine needed very little sanding
3) assemble the halves with the M3x10 screws
If there is a little too much play in the joint sand the print bed side of the casing slightly and re-assemble.
The scad file is parametric and has support for different ball diameters, and a "default" end which seems to work fairly well. The rod end supports square, round and heck tube and rod stock and has the option of adding a screw to hold the stock in (you would need to drill through the stock) or to omit it if you wanted to glue it in.