Double helical gears (sometimes known as Herringbone Gears) give the same advantages and smoothness as single helical gears, but with the added value of a much greater strength in the contact of the teeth and no sideways force or end load on the mounting shafts. They can directly replace spur gears without the re-designing of the mounting bearings excepting the case of more power to be transmitted through the combination. Double helical gears are more difficult to produce due to their more complicated shape and hence more expensive to produce than spur gears.

Double helical gears are used in many applications such as cranes, fluid pumps and power transmission to the propulsion screws in military ships for a quieter and less vibration operation.