I just took a look at my 1969 Philco AM radio which appears very similar to your 67 (?). Mine has a metal arm with a 90 degree hook on the end that fits in the groove on the plastic gear -- just to the right of the embossed "C" in your picture. It appears to be missing in your unit. When a tuning button is pressed, it's this arm that pulls the gear away from the discs and allows the clutch to slip. If I follow you correctly, I would think running a pair of rigid fasteners through all the plates would defeat the purpose of the clutch, forcing the gear to turn with the presets, no?