Adjustable Backplate

Self-centering chucks rarely run 'spot on'. Commercial chucks do exist, which feature inbuilt adjustment to correct for radial run out.  Burnerd's Grip-Tru chucks, patented in 1953, are still the device of choice for fine grinding.    

Our solution to the problem of run out is by means of an adjustable backplate, which uses your existing chuck's backplate and an intermediate iron disc. The mechanism can be centred precisely under the control of 3 fine pitch screws. Not difficult to machine. Our old Ø5" chuck now repeats to within .0015", making collet set-ups seldom necessary.

PLEASE NOTE: This modification is for 3-jaw chucks with a separable backplate - NOT those with an integrated pilot and mounting thread, such as the 'Specially for Myford' labelled Burnerd Ø4" chucks. It is also unsuitable for directly bolted, and cam-lock chucks. Sorry...