I created these snap on brackets to join two or more clothing racks together as well as the ability to mount them to the wall for stability. Inexpensive racks were purchased at Walmart but are not very stable. Joining them together or mounting to wall seems to do the trick.
I have included the stl and blend files if you need to adjust for your own purpose. I printed in PLA lowest setting since quality was not an issue and they seem to snap on and hold well. I printed mine (the ones pictured) in glow in the dark PLA.
The screw holes in wall hanger were just random. Can be adjusted in blend file based on screws you use. Drywall screws seemed to work fine, especially if you are lucky enough to hit a stud. Last image shows mounted version into drywall.
Calipped diameter of support rods and created using cylinders in blender with inside diameter of cylinders matching support rod outside diameters. Simple extrusion to join or create wall mount.