This is a GoPro Tripod adapter. I have a few tripods with the standard screw type bolt with sizes 1/4" and 3/8". I needed to mount my GoPro to these tripods hence I designed this adapter instead of buying one.
There a currently two files, one for 1/4 inch and the other for 3/8th inch tripod mounts.
ONLY an M5 nut is needed for the adapter.
This project is covered completely by my Youtube video at https://youtu.be/sboAQkcIfxk .
Some sanding might be required and the appropriate sized round files may come in handy to clean and shape the holes. An M8 nut is required for the adapter.