[morzh]

Gosh. I always re-discovered how to do it, took me 2-3 minutes every time.
Now that I think of it, the c-clip is there but has nothing to do with taking this apart.
I think you just push that sprocket agaisnt a piece of wood, and it just comes out. You have to push the shaft (the tuning end where the knob goes on) in a bit before pushing the sprocket.
I hope so.

I also found this

https://philcoradio.com/repairbench/tips/svctip39.htm