The mount uses 10mm M3 screws to connect to the handle bars. I've included the .stp so adjustments can be made.

I was having some issues with the print breaking along the layers which is why I oriented the .stl so the mount will print with the layers perpendicular to force applied by the screw.

I glued a nylon lock nut (unsure of the size) that fits the standard GoPro screw on one side of the mount.

This is the first thing I've uploaded, if you have any suggestions or comment please let me know.