Fastener Threaded Shear Area Equation and Calculator ISO 898

Fastener and Thread Design Menu
ISO Hardware Engineering Data
ANSI Hardware Engineering Data
Mechanics / Strength of Materials Menu

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

Thread Shear Area:

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


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.


Rm = Fm/As, nom


As, nom = [π/4] [(d2 + d3)/2]2


Fm = Tensile Load (Measured or Design Load)
d2 = dp Basic Pitch Diameter External Thread per. ISO 724
d3 = Basic Minor Diameter External Thread = d1 - H/6
π = 3.14157
P = Pitch of threads, number per mm
H = Height of Thread Triangle Feature according to ISO 68-1

Height of Thread Triangle Feature