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RE: Sheet Metal Screw Properties

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Donny,
 
I would appreciate a .PDF copy.
 
Thanks,
 
Larry Hauer, S.E.
lrhauer(--nospam--at)earthlink.net
 
> Subject: RE: Sheet Metal Screw Properties
> Date: Fri, 29 Jul 2011 08:47:50 -0700
> From: dharris(--nospam--at)kpff-la.com
> To: seaint(--nospam--at)seaint.org
>
> I admit to previously using the bending stress of screws to justify some
> connections in the past but I agree with Conrad and more recently have
> based designs on a document OSHPD provided over a year ago in draft form
> that gives ASD values for SMS in the typical condition where they are
> installed with gyp between the base and side steel members. Also
> included in this document are values where 1 5/8" unistut is attached to
> gyp with a single line and loaded such that prying controls.
> Coincidently OSHPD has just released the final version of this document
> yesterday. The values are low for shear but as I understand they are
> based on tested values in combination with AISI, ICC and SSMA documents.
> These may or may not be overly conservative but these are the proper
> values to use for all OSHPD jobs (and arguably DSA) in my opinion. It's
> use outside of the OSHPD/DSA environment may not be required but it may
> be used as a tool among other criteria to select the proper fastener.
>
> The document is supposed to be posted on the OSHPD website in the near
> future but if you don't want to wait for the California Government's
> "near future" email me and I will forward a pdf copy.
>
> Donny Harris, SE
> Los Angeles
>
>
> From: "Conrad Harrison" <sch.tectonic(--nospam--at)bigpond.com>
> To: <seaint(--nospam--at)seaint.org>
> Subject: RE: Sheet Metal Screw Properties
>
> This is a multi-part message in MIME format.
>
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>
> Checking Australian code for screws it only specifies minimum forces,
> and states materials are not specified. I hazard a guess that the screws
> are smaller than any tensile test token, and would not give a reliable
> indicator of the strength of material in the screw. The stress
> distribution on the threads and between mating part also complex, so
> have standard tests for the screw.
>
> Also self-cutting-tapping screws also have hardened surfaces to
> facilitate cutting, so the screws may be brittle. So not a good idea to
> place the screws in bending.
>
>
> regards
>
> Conrad
>
>
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