Helical gears, while being more complex to make than spur gears, are much better suited for high-speed applications since the teeth engage more gradually than spur gears. Spur gears engage instantaneously along a line across the whole tooth, but helical gears engage at a point, develop into a line of contact, then separate at a single point of contact. This causes less noise mechanical shock in the tooth. The tooth shape of a helical gear is a segment of a helix, and their shaft axes can be oriented at any angle, though the contact area tends to be optimal when the shafts are parallel [2]. Thrust is generated along the shaft axis in helical gears, which has to be counteracted with thrust, taper, or spherical bearings.

Helical gears, while being more complex to make than spur gears, are much better suited for high-speed applications since the teeth engage more gradually than spur gears. Spur gears engage instantaneously along a line across the whole tooth, but helical gears engage at a point, develop into a line of contact, then separate at a single point of contact. This causes less noise mechanical shock in the tooth. The tooth shape of a helical gear is a segment of a helix, and their shaft axes can be oriented at any angle, though the contact area tends to be optimal when the shafts are parallel [2]. Thrust is generated along the shaft axis in helical gears, which has to be counteracted with thrust, taper, or spherical bearings.