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. The two halves are unioned into one editable part, aligned so the teeth run continuously across the join. To build a whole meshing line of them, use the herringbone train.

1. Set the module, tooth count, and pressure angle.
2. Set the helix (chevron) angle, total thickness, and bore.
3. Generate: the gear drops in as one editable part.