This workbench creates full-size outlines for plywood gears. Start with a preset, then choose the diameter, ratio, and tooth spacing. Gears mesh because every wheel in a train uses the same tooth spacing and pressure angle.
Tooth spacing is measured along the pitch circle from one tooth to the next. A larger pressure angle makes stronger, more sloped teeth and is useful for small wooden pinions. The displayed diameter is a target; it may be adjusted slightly so the gear has a whole number of teeth.
Use Play to inspect the mesh and zoom into the contact point. The dashed pitch circles should touch at the working center distance. “Line of contact” shows the direction along which involute teeth transfer force. Rotation offset lets you inspect the fit at another position.
Set the shaft hole before export. Use the centimeter grid and 100 mm check bar to verify scale. If a printed 100 mm bar measures 99 mm, set calibration to 101.0%, export again, and recheck. Print with browser scaling disabled or set to Actual Size.
These are practical cutting templates, not production engineering drawings. Use stable, fine-layer plywood, cut on the waste side of the line, and test the pair by hand before applying power.