I built this as a way to mount my home made Osmo Jib to a tripod. You will have to modify the file for your own specific bolt and nut sizes.

I used parts from home depot to complete the project.

http://www.homedepot.com/p/Blackburn-1-2-1-in-Zinc-Ground-Clamp-BJ1-B1-25/202907602

Hope it's helpful to those out there making their own camera equipment.