Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations MintJulep on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
machine screws
- Thread starter sfstruct
- Start date
- Thread starter
- #3
sfstruct,
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.
JHG
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.
- Thread starter
- #5
Thanks for your help. This is for the connection of a sliding glass door to header in an office space. The header is steel and will have a tapped threaded hole to receive the screw. I was hoping there might be book values for shear and tension like AISC has for bolts but it sounds like maybe not.
Maybe I'll look more into the airline industry and see if they have references for connectors.
Thanks.
Maybe I'll look more into the airline industry and see if they have references for connectors.
Thanks.
Have a look at MMPDS, formerly MIL-HDBK-5, chapter 8. This is the "standard" reference for aero fastener allowables.
You can get MIL-HDBK-5 for free, see this thread for more explanation of the availability of these references:
You can get MIL-HDBK-5 for free, see this thread for more explanation of the availability of these references:
- Status
Similar threads
- Locked
- Question