[Doug Brance]

I made my tool using welding rod, I think coat hanger would work too. Heat it to red to anneal (soften) the steel, about 2" & let it cool naturally. Then pound the last 1/2" to a long chisel point. Next bend it 90° where the chisel point begins. Reheat it to gray, just under red & quench it in water or used oil. The quench should not be too important here. You may need to file the edges to narrow it enough to get it to slide in between the inside of the knob & the shat on the switch. It will be L shaped. Then insert it & pry the flat spring down & pull the knob back.

Worked for me.