ISO 6336 Tooth Bending Strength: The Complete $S_F$ Calculation Walkthrough
A complete derivation of the ISO 6336-3:2019 tooth bending safety factor $S_F$ — including $Y_F$ from tooth root geometry, $Y_S$ stress correction, $Y_ST$ = 2.0 and why it exists, $Y_B$ rim thickness, $Y_DT$ double tip loading, and the five errors that corrupt bending calculations in practice. Method B, external cylindrical gears.