Not that I know everything about this topic but there are commonly used pitches on various diameter bolts or nuts (or spindles axles etc) most applications have more than one world wide standard (ISO/DIN/JIS etc...) even very small diameter fasteners have multiple pitches available. The metric pitch gauges should have everything but the difference between .70 and .80 are quite small.. Many hardware stores have metric assortments but be prepared for the fact that they dont have everything (and neither do I) Dave Martinez just used a thread restoration file to repair some pedal threads and I recommend them , sometimes you can find them with a end that will restore inside threads also
BOB FREITAS sunny MILL VALLEY, CA USA
who even sells 1/4 inch bolts with metric 1.0 threads (shame on you GM)