In a message dated 9/24/01 6:52:07 PM Eastern Daylight Time,
DLancer7676@cs.com writes:
> While the Grade 8 is more brittle, as in not as flexible and "stretchy" as
> the Grade 5, the brittleness does not become a factor until well after the
> grade 5 bolt has stretched and groaned and broken. For instance, a Grade
> 5- 7/16" Fine thread bolt has a proof load of 10,100 lbs. and a tensile
> strength of 14, 240 lb. A Grade 8-7/16" Fine thread bolt has a proof load
> of 14,250 lb.(equal to the TENSILE strength of the Grade 5) and a Tensile
> strength of 17,800 lb. So while the Grade 5 fastener is stretching to its
> tensile strength of 14,240 lb. the Grade 8 is just getting started.
>
> There IS a happy compromise: The Bowmalloy bolt, produced by Bowman,
> headquartered in Cleveland (1-800-726-9626). The Bowmalloy 7/16" Fine
> thread bolt has a proof load of 18,520 lb and a Tensile strength of 21, 370
> lb. No financial interest, and I have never used the Bowmalloy, but I have
> seen it demonstrated and it ranks well above a standard Grade 5 or 8.
- - - - - - - - - -
Thanks for the info Dave. Since you have numbers to back you up, I'll take
your word for it. And it was a good explanation.
BTW, I worked for Bowman for about a year doing sales. That was the
advertising hype about Bowmalloy hardware, and I have no reason to refute it.
We sold to municipal maintenance shops, school bus barns, oil well
companies, etc. I learned a lot just from reading the Bowman catalogs.
Allen Hefner
SCCA Philly Region Rally Steward
'77 Midget
'92 Mitsubishi Expo LRV Sport
|