Agma 21801 Pdf Jun 2026

For years, the AGMA 218.01 PDF (or its physical binder) sat on the desk of every serious gear designer. It was a dense collection of complex formulas for calculating exactly how much stress a gear could take before it pitted (surface fatigue) or snapped at the root (bending failure). The document became the guardian of safety for: Movable Bridges:

Bending fatigue occurs at the root fillet of the gear tooth, where the tooth connects to the gear blank. As the tooth loads and unloads, tensile stresses concentrate in this fillet. If these stresses exceed the material's bending limits, a crack propagates, eventually breaking the tooth. AGMA 218.01 calculates the bending stress number ( ) against the allowable bending stress ( sats sub a t end-sub 3. Key Mathematical Formulas in AGMA 218.01 agma 21801 pdf