ARC-5 Receiver Knob

This project was given to me at my old college. The Ark 5 receiver knob is "rarer than hens teeth". I was provided one in the shop and used a optical comparator and my calipers to reverse engineer the inside teeth. Then I designed a Knob that could be attached to the hole assembly so the Ark 5 could be tuned. The threads can not be printed reliably on most FDM machines. I solved this by using making a simple nut that slides over the threads to hold the assembly in place. The knob is Keyed into the assembly and has a tapper on the inside keyway to get a snug fit.

Printing Notes
Any FDM machine with a decent tune should print these just fine. I ran my ender a little slower than normal to get the ID teeth to print well. I would adjust the size +/- 5% based on how your machine prints. This makes sure the ID teeth grab well.