Hold down clamp for whatever

Pretty simple Hold down that i designed for use with a CNC router.
Hole is a good size for a 8mm or 5/16 tee bolt, 1/4 would be loose but would work fine.
He already had the bolts and routed out a nut holder, but wing nuts and a washer would work great.
It is actually really strong, it conforms from 1/8 inch to 3+ inches tall material.