Gear design guides

Reference notes on the maths behind involute and planetary gears, written from the same equations GearStudio runs. The calculators on these pages use the app's own code.

Planetary gears

Planetary gear ratio calculator and formulasThe Willis equation, ratios for every fixed and input member, and a worked example. Planetary assembly conditionsThe coaxial, equal-spacing and neighbour rules that decide whether a set can be built.

Involute tooth geometry

Undercut, minimum tooth count and profile shiftWhy small gears undercut, minimum counts by pressure angle, and how much shift fixes it. Module vs diametral pitchConversion charts, a converter, and basic tooth dimensions.

Strength

Gear stress analysis: Lewis vs AGMA J and I factorsBending and contact stress, allowable stresses, planetary specifics, and a calculator.

Manufacturing

STEP vs STL vs DXF for gearsWhich export to use for CAD, CNC, 3D printing and laser cutting, and what each contains.

GearStudio designs planetary gear sets in the browser, checks them as you go, and exports STEP, STL, DXF and SVG.

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