SAE Technical Paper 770420: Analysis and Design of Threaded Assemblies

[pperlich]

In Appendix A, there is a symbol, T[sub]D1[/sub], for which I find no definition.
I can only guess that this symbol represents the tolerance on D[sub]1[/sub], Basic Minor Diameter, Internal.
Is this correct, or is this some other value?
Thanks!

EDIT: Concerning the discussion of Bell-mouthing in section 2.1 (and in appendix A): should I just multiply the minor diameter of the nut by 1.03, and apply it over the entire length of the nut to be conservative and save time trying to track this information down?

 

[TVP]

Yes, T[sub]D1[/sub] refers to the tolerance for minor diameter of internal thread. ISO 965-1 has the relevant equations for calculating the value. And yes, the method you described should be conservative for analysis of bell mouthing.

 

[pperlich]

Thanks, TVP.

Now I have another problem. I need the tensile stress of the nut material, but the specs I look at for nuts do not have tensile stress requirements for the material. (I'm looking at A563 and A194.)
What should I use for the tensile stress of the nut material?

 

[CoryPad]

Use the hardness values in Table 3 of ASTM A563 and Table 2 of ASTM A194 and convert to ultimate tensile strength using ASTM A370.

 

[pperlich]

Thank you, CoryPad. I was hoping you would see this thread. I saw an another thread where you mentioned this text. I wanted to just send you a private message with my initial question, but apparently this forum doesn't have that function.

I went through the example in the text again and saw that statement about determining tensile stress via hardness about an hour ago. It was a "DOH" moment for me. Something I should have thought of myself.