I have to cut out several 7 7/8" cirles in 3/4" mild steel plate.
I saw somewhere a guy cut circles on his bandsaw with a subplate on the table and a dowel pin in the subplate.He would drill a hole in the centre of the square that he was cutting the circle out of and place over the dowel pin on the subplate on the bandsaw table.Then turning the square,he cut out the circle.
Only HE was doing this with wood.
Think it would work in 3/4" plate
These DO NOT have to be perfect.