Good information to follow in posts, 3,6,11,17,19 . BTW, hardware store bolts if used in critical clamping applications, at the very least try to verify the bolt manufacturer. Lots of them are Chinese sourced grade 8 fasteners. They are NOT to be trusted as real grade 8. They could be anything from non-graded to grade 5. Chinese put a grade 8 head marking on them and out the door they go. I have had 2 situations now where fairly large "grade 8 fasteners" failed in a shear situation. One was on the caster wheels of an engine hoist. "grade 8", Ha. Rolled the hoist over an expansion joint in the concrete floor and the bolts sheared off like they were made of plastic.
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