Fixing a Stuck Switch on a Vintage Circular Saw

The switch on my powerful 1970s 71/4 inch Super Sawcat on the left was sticking and then froze in the on position! Not exactly a safe way to operation a powerful cutting tool. No replacements are available anymore so I found a similar saw, a Builders Sawcat to use for parts ( on the right) but its in too good a shape to cannibalize. Plan B was to take the switch apart and attempt to repair it. I found a quick non destructive fix that worked instead.

Supplies

Screwdrivers to disassemble the saw handle with ( like many old tools it had been repaired previously and required Flathead, Robertson & Phillips screwdrivers) . Electric heat gun. Safety gloves

Step 1: Assessing the Problem

When I tried my original saw there is no click & it just runs and won't shut off unless I pull the plug.

When I tried the Saw I got for parts the switch makes a very healthy click. and works turning the saw on when pressure put on the switch and cutting the power when pressure is released. Having a comparison to know how it is supposed to sound helps. Even when it worked I don't remember it clicking like that.

Step 2: Assessing the Problem Part 2

When I first disassembled the handle the switch was easy to access and there even was a circuit diagram! I looked online for replacement parts but nothing of that vintage is available anymore and this particular switch has 6 attachment points for wires and any possible modern replacements I might try only have 2 or 4 wires. A second saw I found for parts turned out to be too good to use for that purpose.

Step 3: Attempting Plan C- Non Destructive Repair

Original plan was to drill out the rivets and take the switch apart, lubricate it and hopefully get it back together in working order. Before I started drilling into it I thought about what non destructive options might work. The switch has a brown bakelite like body and opaque plastic on the bottom but no holes or places i could try spraying in contact cleaner. Then I thought to try heating it with an electric heat gun on low setting. That worked!