Fastener Threaded Shear Area Equation and Calculator ISO 898

The following equations and calculator will determine the Shear Area For External Thread Screw or Fastener per. ISO 898.

Ath = 0.5 Π dp Le = 0.5 Π Le ( D - 0.64952 p)

Where:

Ath = Total thread shear area (mm2)
Le = Thread Engagement Length (mm)
dp = Pitch circle diameter of thread (mm)
D = Major Diameter (mm)
p = 1 / Number of threads per mm (n)

Per. ISO 898, Calculation of the tensile strength, Rm is based on the nominal stress area As, nom (single full thread) and the ultimate tensile load Fm.

Equation:

Rm = Fm/As, nom

Where

Anom = [pi/4] [(d2 + d3)/2]2

Where:

D = Nominal (Major) Screw Diameter
d2 = Basic Pitch Diameter External Thread per. ISO 724
d3 = Basic Minor Diameter External Thread = d1 - H/6
H = Height of Thread Triangle Feature = 0.866025p
pi = 3.14157
p = Pitch

Atnom = [pi/4] [ (D - 0.75 x 0.866025 x p + D - 1.25 x 0.866025 x p - 1/6 x 0.866025 x p) / 2]2

or

Atnom = [pi/4] [D - 0.938194 x p)2

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 Input Data Major Diameter D (mm) = Thread Engagement Length Le (mm) = Pitch circle diameter p (mm) = Basic Minor Diameter d1 (mm) = Ultimate Tensile Load Fm (MPa) = Results Shear Tensile Area Nominal Ath ( mm2) = Height Thread Triangle H (mm) = Basic Pitch Dia. d2 (mm) = Basic Minor Dia. d3 (mm) = Shear Tensile Area Nominal At, nom ( mm2) = Tensile Strength Rm (N/mm2) =

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