Herringbone gear

A chevron gear whose opposed helices cancel axial thrust.

A herringbone gear is two opposite-hand helical halves meeting in a chevron. The opposing helix angles cancel the axial thrust a plain helical gear produces, so no thrust bearing is needed — which makes it a favourite for 3D-printed drives. It is built as one solid whose teeth turn up to the middle and back, so the chevron runs continuously with no join at its point. To build a whole meshing line of them, use the herringbone train.

1. Open the Generate panel from the left sidebar and choose Herringbone gear (under Gears & drives).
2. The gear drops in as one editable part. The parameters open in the Properties panel, where you set them.
3. Set the module, tooth count, and pressure angle.
4. Set the helix (chevron) angle, total thickness, and bore.