Hello all so I am still fairly new to machining and do a lot of welding and repair work etc . I have a 8” Cushman 3- jaw chuck and want to make a back plate with a D1-6 mount so I can use it on my Monarch lathes . My question is how thick it should be and then the chuck measure 8-1/4” I have a piece is solid round stock that measured 8-1/8” . Will that work as long as it doesn’t effect the 3 mounting screws that secures the chuck to the backing plate ??