cylindrical gears

ISO 6336 Tooth Bending Strength: The Complete $S_F$​ Calculation Walkthrough

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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.

ISO 6336 Pitting Resistance: The Complete $S_H​$ Calculation Walkthrough

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A complete, factor-by-factor derivation of the ISO 6336-2:2019 contact safety factor $S_H$ — including $Z_B$/$Z_D$, $Z_NT$ for long life, the $Z_W$ asymmetry, and the three calculation errors that appear in practice. Method B, external cylindrical gears.