Just for kicks I put a 3/8 bolt in my vise with the threads flush with the top of the jaws..I beat on it with a 4 lb sledge from the side. It broke when it was bent over 45 degrees and the weak point at the threads fractured..Then I put another in the vise and used a 1 inch steel block against it flush, to try to shear it off. The bolt was dented but would not even bend...You can't shear off a 3/8 bolt with a prop, be it wood or carbon, because there is no shear force against the bolt, just tension..The shear is on the other bolts, if the center bolt and all the others get loose...Even then the prop usually stays on the engine....
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