I thought I could add a bit to the tab washer, bolt discussion.
About fifteen years ago while employed in building railway freight
cars, we had a salesman demonstrate the reason to use new bolts instead of
the ones removed especially where there is concern about the compression
forces when a bolt is torqued.
He had a device fitted with a strain gage to measure the gripping
force (lbs) that a bolt exerted when torqued to a set value. He torqued a
new bolt into the device and measured the reading on the dial attached to
the strain gage. He then removed the bolt and then reused it torquing it to
the same value as when installed new. The gripping force was considerably
less than when the bolt was new (unused).
After seeing this demonstration, I've often wondered if it would be
advisable to use new bolts when rebuilding engines especially for heads,
main and rod bearing caps.
Bob Hamilton
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