Bevel gears

Two straight bevel gears that turn the drive round a corner.

Bevel gears turn the drive round a corner. Their teeth lie on cones whose tips meet at one point, so the two shafts meet there too: at 90° by default, or at any angle from 30° to 90°. The reduction is gear teeth ÷ pinion teeth, as for spur gears, and the shaft angle decides how the two cones share it. The teeth are true straight bevel teeth (the standard back-cone tooth form), narrowing toward the tip of the cone, so the pair rolls without binding. The module is measured at the heel, the wide end.

The face width is held to a third of the cone distance, the usual limit: past it, each tooth gets too thin at the toe. Everything shrinks toward the toe, the gap between the teeth included, so the default backlash is sized for the toe, and the Print gap read-out gives the gap there.

1. Open the Generate panel from the left sidebar and choose Bevel gears (under Gears & drives).
2. The pinion and the gear drop in meshed at their shaft angle, as separate parts. The parameters open in the Properties panel, where you set them.
3. Set the module, pressure angle and the two tooth counts. Equal counts at 90° make a mitre pair.
4. Set the shaft angle, the face width and the two bores.
5. Before you print, set Layout to For printing, which stands both gears heel-down side by side.