Bench dog for 6mm bolt

I don't have dog holes in my CNC. Instead I have 6mm bolts which screw into threaded inserts in the CNC base. This is an excellent system, but doesn't allow one to use bench dogs. So I made some bench dogs that use a 6mm bolt through the centre to fix the dog in place. Works flawlessly. I also recessed the top surface to accept a 12mm washer to spread the load.