Bump Switch

I’ve had the same Snap-On MT302 starter switch for the last 40 years. Still looks and works good. You could definitely build one cheaper than the new ones. Just make sure the switch you use is rated for enough current to run the starter motor. The new Snap-On switches are rated at 40A@12V, and that would be a good standard to work to. I sold dozens of these things of my truck when I was a dealer, and they were rock-solid. You could also get parts if someone tore one up. I’ve used a screwdriver too, just not a Snap-On. Sparks in the engine bay aren’t a good thing, however.