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Re: ASTM A307 Bolts

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>The motivation is that these bolts are slightly cheaper.  His
>argument is based on the claim that ANSI B1.1 (which we do not have a copy
>of) which is referenced from A307, reportedly lists rolled threads as an
>option.
ANSI B1.1 provides thread form standards. It's not a material standard.
My old copy of A-307 specified that the thread form shall accord with
B1.1 and allows for either rolled or cut threads. Personally I think
rolled threads are better from a fatigue standpoint.

>This causes problems since the bolt shank is slightly smaller which results
>in a weaker bolt and results in a larger space between bolt and the bolt
>hole.
This isn't true. Besides, the bolt shank isn't covered in B1.1 and it'd
be larger than the root diameter anyway.

To risk sounding like an old fart, you're the engineer and you really
should know the content of a standard you call out. Your contractor is
absolutely right about rolled threads--it's permitted by A-307. The shank
diameter is covered by B18.2 (Also stated in A-307) If the contractor is
saying he can use bolts which don't conform to B18.2, he's wrong. You can
get the necessary content of B1,1 and B18.1 from Machinery's Handbook.
Probably some of the old farts around your office have a copy...

Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw


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