I wanted one for my lightforce lamp
I didnt want to pay £40 Or have a switch stuck to my stock
I bought a pigeon magnet speed controler for £19 and made this:
Took 30 minutes with a craft knife, snippers, screwdriver, glue gun and a spanner to bolt it to the lamp
using the original bolt through the hinge arm of the lamp.
Full power to off in the twist of the wrist