Thread Shear Area Formulas and Calculator per. ASME B1.1

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Thread Shear Area Formulas and Calculator per. ASME B1.1

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Thread Shear Area for External and Internal Formulas and Calculator per. ASME B1.1

The following formulas for thread shear areas are geometric minimum values. Shear ( thread stripping) strengths of screw threads under load are dependent, in addition, on mating component relative material strengths, nut geometry, and coefficient of friction between thread bearing surfaces. Effective shear areas are therefore somewhat less than the geometric values.

Preview- Thread geometric shear areas calculator

Thread geometric shear areas:

Eq. 1
A_s = π · n · L_e · K_nmax [ 1 / ( 2 · n ) + 0.57735 · ( E_smin - K_nmax) ]

Eq. 2
A_n = π · n · L_e · D_smin [ 1 / 1/n + 0.57735 (D_smin - E_nmax )]

For thread dimensional data see:
External Screw Thread Pitch, and Major Diameter Data

Internal Screw Thread Pitch, and Major Diameter Data

where

A_n = minimum thread shear area for internal threads
A_s = minimum thread shear area for external threads
1/P = number of threads per inch
L_e = length of engagement
K_nmax = maximum minor diameter of internal thread
E_smin = minimum pitch diameter of the external thread for the class of thread specified
D_smin = minimum major diameter of the external thread
E_nmax = maximum pitch diameter of internal thread.

Reference:

Machinerys Handbook, 30th Edition