made a tool to center my rotary table with chuck,, the chuck has a center bore and bolts to the adapter plate,, the plate has bosses that align it the table and to the chuck,, test found that the center bore was very concentric.. turned a smooth fitting shaft to fit the bore (it slides down with a piston like feel) top of the shaft has a 3/16ths hole centered.. put a 3/16ths shaft in the collet and brought down the head,, adjusted the table so the shaft aligned with the hole,, repeated this rotating the table 90 degrees at a time,, all stayed centered.. zero the DRO's and ready the chuck things up..
