A better way of fixing the vice to the 3/4" ply would be to use threaded inserts screwed flush into the bottom face of the ply, then, bolt the vice to the ply using bolts Just long enough) from the top side. When you remove the ply from the workmate the threaded insert stay with the ply till next time.
Hi John great workmate hiw to videos. I have a WM 225 with one board missing (the one not connected to the adjusting screws) and was thinking of making 2 board tops (duplicating the original one I have so both are even thickness) what is the dimensions of the 2nd board and is it possible to make 3 boards like the 425 and if so what are the dimensions of those boards? Thx in advance.