Since a long time I had in mind to design a 1/32 scale knuckle coupler to replace the oversized LGB coupler on my US rail cars. After a few inconclusive tries I finally found an easy to print and functional design.
The automatic coupling is working as expected and it doesn't unhook even in tight curves. It also interfaces correctly with a 820 Kadee coupler (and probably with other brands too). The springs are printed so no need for small, pricey and hard to find steel springs.
Printer:
Vertex K8400
Rafts:
No
Supports:
No
Resolution:
0.1 mm
Infill:
30-40%
Notes:
Printed in ABS as there are 2 parts to glue and it's less brittle than PLA ( butyou can glue the PLA with super-glue so it works too).
The two moving parts must rotate freely. If not file the holes a bit.
The parts # 2 & 4 must be glued on the flat side of the hook (01) and jaw (02).
There's a hole under the claw part. It can be used to insert an iron rod (needed if you want to use an uncoupling magnet) - do not use stainless steel as it's not magnetic! Personally I don't need it. It's easy to manually uncouple the cars. You just need to insert a small flat screwdriver between the couplers and give it a twist.