machine screws
machine screws
(OP)
I have been unable to find allowable shear and tension values for machine screws. 1/4" diameter and smaller. Does anyone have a reference?
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RE: machine screws
What kind of machine screws?
RE: machine screws
RE: machine screws
Probably, you will have to work it out, depending on your material. Stainless steel screws are mostly austenitic, subject to work hardening, and frequently annealed. Stress values are all over the place. I use 55,000psi as a yield stress because I found a vendor website that claimed that their cap screws were that strong. The metric standard A2-70 and A2-80 are required to meet yield and ultimate strengths that are higher than that. How much do you trust your vendors and suppliers?
The yield stress of annealed 303 stainless is 35,000psi.
Is this like an ordinary thing you want to build, or is it subject to regulation of some kind? Most machine screws are commodities, not subject to the process control that structurally critical fasteners are.
I have asked a Designated Airworthiness Representative what kind of screws he likes to see in airborne equipment. He told me he liked the MS24694 flat head, and the MS27039 pan head structural screws. These are nice screws, and they are not horribly expensive.
RE: machine screws
Maybe I'll look more into the airline industry and see if they have references for connectors.
Thanks.
RE: machine screws
You can get MIL-HDBK-5 for free, see this thread for more explanation of the availability of these references:
http://www.eng-tips.com/viewthread.cfm?qid=188116