Morgrip propeller bolt single-use replacement

Student-recalled shipyard experience confirms Tom's general rule: high-strength bolts (propellers, aircraft, bridges, racing cars) are one-time-article use because reuse degrades thread fit-up via micro-yielding and shifts torque-vs-preload calibration.

The other problem with reusing bolts: bolts are often loaded to about 75% of their yield strength. Bickford's book talks about that. If you do that and then put some service loads or excursions on top of that 75%, you'll often start to yield the threads. It might be micro-yielding, but now things don't fit up quite as well. So typically you never reuse high-strength bolts. They're one-time-article use. Who was talking about Morgrip bolts and propellers? One of you had an experience — you probably didn't reuse the Morgrips, did you? Threw them away after one use.