This standard presents the fundamental formula for the strength of helical and herringbone gear teeth. It includes all of the factors which are known to affect gear tooth strength. This formula and standard is based on AGMA Information Sheet 225.01 and therefore coordinated with strength ratings for spur and bevel gears.

Both pinion and gear teeth must be checked for bending strength rating to account for differences in geometry factors, material properties, and numbers of tooth contact cycles under load.

Other AGMA standards contain numerical values to be used to rate gears for specific applications. These should be consulted when applicable.

Where no applicable specific AGMA standard is established, numerical values for the factors may be estimated from the data given in this standard and the strength rating calculation.

The formulas presented in this standard apply to external gears unless otherwise noted.

The symbols used, wherever applicable, conform to Standard AGMA 112.04, "Terms, Definitions Symbols, and Abbreviations" and "Letter Symbols for Mechanics of Solid Bodies" (ASA Z10.3-1948) (R1953).