Originally Posted by
noglider
You should be able to get away with screwing them into an English-threaded crank. I did that for a while, and I didn't ruin anything. Make sure they're tight but not too tight. Sorry I can't quantify what those terms mean.
Or maybe use some shim material? Plumbers tape?
That seems like a really bad idea, given that French-threaded pedal spindles are a fair amount narrower in diameter than English (though it is convenient for tapping French-threaded crank arms to English thread). Sure, use lots of layers of plumber tape, but they'll fall out in short order and probably munge up the threads while they do.