clare at snyder.on.ca wrote:

In double shear a loose grade 8 will snap uner impact. A grade 5 will
flex. It MAY permanently deform,
A loose grade 8 bolt in shear WILL brake on impact.

You forget to consider the forces.
A grade 5 bends under a certain load, where the grade 8 doesn't even bend
with the same load. Wen the grade 5 breaks, the grade 8 just bends.
Again, a bolt that is plastically deformed by design is simply an error.

Facts (metric grades):
grade 5.6 : 500N/mm^2 and 300N/mm^2
grade 8.8 : 800N/mm^2 and 640N/mm^2

A bit simplified:
The grade 5.6 bends at 300N/mm^2 and breaks at 500N/mm^2
The grade 8.8 bends at 640N/mm^2 and breaks at 800N/mm^2
So the grade 8.8 doesn't even bend when the grade 5.6 already failed
completely.


Nick
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