"When I sand the drum and apply the brakes it puts metalic bits in the brake shoes reducing their effectiveness. Taking them apart and sanding the metal out of the shoes and you are good."
Steve, do you mean that after you sand the insides of your brake drums, you have to use your brakes a few times and then clean them out?
I don't think I've ever done this intentionally, but it sounds like a good idea.
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Campbell, yes, that friction fit holding your metal strip in will be pretty strong. Also, the pressure on the cam won't stop unless the springs in your brakes fail, at which point you've got all kinds of problems anyway.
Still, while I like the simplicity of this idea, I'm still wondering how you could tweak it to make it a near-permanent modification.
What if you used a thinner strip of metal that wrapped around more than once? Then, you could coat the strip of metal with flux, and use a torch to braze it all together with some solder (or, ideally, with some brass).
In case I ever have to do this (and I probably will - I've got a whole mess of random drum brakes for bicycles, mopeds, and motorbikes), what kind of steel are you using as a wrap? Standard-gauge sheet metal thickness, or cheap cookie-tin thickness?
If it's the former, then the brazing idea might work well with the latter.