Wollensak T-1500 (or T-1510) Tape Recorder On/Off Knob

I've had this Wollensak T-1500 tape recorder since 1960. It was (and is) a workhorse reel-to-reel tape recorder, which many who are old enough will remember seeing in their schools, churches, and workplaces. They were everywhere.

Sometime in the 1970s, the knob that not only turns the unit on and off but also controls the tone during playback broke. It broke because of the torque on the center piece of plastic when it activates the switch in the combo rheostat and switch. All attempts to fix