They shouldn't be Grade 5 or any high-strength material - Grade 5 is tough,
resisting breakage despite bending.
Use a plain old hardware store bolt if you have to cut your own grooves -
it's supposed to break if it needs to.
> Neither the original ones (which are pins, held with cotter key) or the
> replacements, which are threaded, have any grade makrings on them.
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