I wanted my tripod and monopod to be able to hang off the side of my camera storage case so I made a holder that a standard 1/4-20 thread screws into.

After printing, get inserts such as McMaster #90267A571 or Home Depot #610169. Heat up the insert, and push it into the plastic hole. Once you align it (I used a bolt), run it under water to keep it in place. The screw holes are for #8 countersunk screws to mount to whatever.