Do you know by chance what the thread size is on the screw? I guessed M12 but I think it's 1/2" ?
EDIT: I measured the cap screw and determined it is M13 x 1.5mm thread. I'm working on threaded inserts for other putter grips to accept the Superstroke counter-core system. I'm adding it to my arm-lock project with superstroke flatso-17 grip without tech-port.