<VV> Bolt Grades

[Chris & Bill Strickland]

Dave Thompson wrote:

>It seems to me that a bolt that takes so much stress and is subject to breaking should be a grade 8. 
>

I have not done any comparative testing of bolts, but what I understand 
is that while Grade 8 (and higher) bolts do have a higher tensile 
strength, they are overall more brittle than Grade 5 bolts, and are not 
perhaps the de facto 'best choice' for some applications, especially 
those taking a lot of high shock loads and abrasive wear. Perhaps the 64 
Corvair spring bolts fit into this category -- I don't know -- I do know 
I put in 8's my cars (with Grade 9 nuts). Maybe the factory bolts were 
nitrided?   <wag>

I am sure that if further information is required, it could be found on 
the internet, and if someone looks and finds such, I would appreciate 
their sharing of the information.

Thank you,

Bill Strickland