I have always wanted a tuning peg turner for my guitars. They are simple, inexpensive, and very useful for changing the strings on your guitar. For some reason, I could never bring myself to spend the $20 to buy one. So recently I decided to design and make one using one of the Ultimaker3 printers in the office.  I also wanted to learn how to use freeform tools in Fusion 360 and to exercise some rusty manufacturing engineering muscles.


On the principle of keeping designs as simple as possible, my first attempt was to make a two-part design where the knob snapped onto the part that goes over the tuning peg. This resulted in a part that was weak and did not revolve well when turning the knob. Actually, the parts just flat out broke when I tried to use them.

Plan B was to replace the snapping mechanism with a machine screw. Now my design is three parts, still pretty simple, and works great!