Allowable loads on small diameter fasteners
Allowable loads on small diameter fasteners
(OP)
AISC provides tabulated allowable shear and tensile stresses for ASTM A307, A325, and A490 structural bolts. When dealing with small fasteners such as SAE J429 Gr 2, 1/4-20 screws, where can one find specifications for allowable shear and tensile stresses similar to what is found in AISC? For example, Fv = 0.4Fy and Ft = 0.6Fy.
Also, this fastener is under large tensile load due to the torque recommended by the manufacturer. If I check the tension in the fastener due to the preload, it seems excessive. Is there a different specification for maximum tension on a preloaded fastener such as 0.9Fy? This joint requires a clamping force (hence the torque), and it experiences combined shear and tension loads (seismic).
If helping, please reference a legitimate source for fact checking if available. Thanks for any assistance.
Also, this fastener is under large tensile load due to the torque recommended by the manufacturer. If I check the tension in the fastener due to the preload, it seems excessive. Is there a different specification for maximum tension on a preloaded fastener such as 0.9Fy? This joint requires a clamping force (hence the torque), and it experiences combined shear and tension loads (seismic).
If helping, please reference a legitimate source for fact checking if available. Thanks for any assistance.





RE: Allowable loads on small diameter fasteners
Have a look at this reference:-
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also this site:-
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desertfox
RE: Allowable loads on small diameter fasteners
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RE: Allowable loads on small diameter fasteners
Is this a trick question?
http://standards.sae.org/j429_199901
RE: Allowable loads on small diameter fasteners
RE: Allowable loads on small diameter fasteners
I'm not sure if the SAE spec or manufacturer data will answer this question. The question is, how does one calculate the allowable stress on the cross section of a bolt (those not covered by AISC)? I see that Fy and Ft is specified for the different types of fasteners. I'm assuming that normal practice is to use Ft as your maximum applied tensile stress. But what about shear? Do you use a percentage of the yield such as 0.4Fy? And who is the design authority that determines the methodology used for calculating shear and tension allowables?
I will check out the links and resources that have been recommended. Thanks!
RE: Allowable loads on small diameter fasteners
http://www.boltcouncil.org/Publications.html
Methods for analyzing pretensioned joints are included in VDI 2230 Systematic Calculation of High Duty Bolted Joints. A value of 90 % of the screw tensile yield stress is common. This is available for purchase at Beuth:
http://www.beuth.de
RE: Allowable loads on small diameter fasteners
You must not forget that this for properly marked fasters not for most big big items.
http://www.engineeredpartsinc.com/