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Brian Whatcott Brian Whatcott is offline
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First recorded activity by BoatBanter: Jul 2006
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Default Strength of a 316 PH Machine Screw 1/4x20 ?

On 1 Sep 2006 09:10:02 -0700, "Bob" wrote:

Hi Everyone:

How much pull can a 316 SS PH Machine Screw ¼ x 20 handle before it
fails?

Basically I want to know how many fasters I need to use to secure some
deck hardware.

///
Bob


Annealed 316 wire yields at a pressure of 34,800 lb.
[see Matweb]

The cross section area of a 1/4 in X 20 tpi screw is about
pi X r X r square inches where r is the effective radius.
Using r = 0.06 inch gives a = 0.011 sq in
so the force at yield is about 0.011 X 34800 lb
That's about 390 lb.
The bolt will break before the nut.
You could give a X5 safety factor and take the maximum
unit load as 75 lb each.

You're welcome

Brian Whatcott Altus OK