This is simple but effective clamp with locking top piece for your CNC machine. It is made for M5 or M6 diameter bolts.
The locking wedge piece on top stops any back and forth movement.
Low profile lip - easy for dust collector to pass over
I print them on their side with 5 outlines or shells, 80% infill. You want it pretty solid. I use supports for the "slot".
Added clamp and wedge with 7mm hole.
Jan 2019, added clamp and wedge with 8mm hole.
Feb 2019 added Runt Clamp