Does anyone know of a resource for min and max pitch diameters of self tapping screws (i.e. TEK Screws)?
ITWbuildex doesn’t provide any of this information, so for my calculations of Asn per the ADM05 (ref. Eq. 5.4.2.1-3) I always use the external thread stripping area formula as found here:
http://www.engineersedge.com/thread_strength/thread_bolt_stress.htm
and the values for the various diameters from
http://www.lubkerdist.com/guidepdf/Stdrill.pdf
and then use the ave. between T-max and t-min as my value for the min pitch diameter… which I understand to be a decently close estimate for tightly spaced threads, but self-tappers are slightly loose…
even better, would anyone happen to know of a better formula than the one I’m using?
Richard Calvert, EIT
Lindemann Bentzon Bojack
Architects & Engineers
tel: 352.242.0100 ext.141 fax: 352.242.0302
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