This is a remix of the wrist connection part shared by the Swindon Makerspace for the Heathkit Hero Robot. I found their part to fit rather loosely on the arm tube of my Hero, so I modified the design a bit.
- I reduced the diameter of the central hole to make a tighter fit on the arm of the robot.
- I added small holes above each nut slot. These make it easier to reposition the nuts when installing screws, and make it possible to eject the nuts altogether if you need to.
- I added a chamfer to the bottom of each nut slot. If your printer makes a bit of an elephant foot at the bottom of your prints (due to a squished first layer), it closes up the slots in this part and makes installing the nuts difficult. The chamfers eliminate this problem.
As this is a mechanical part, I recommend printing it with at least three perimeters and a healthy amount of infill.