But a line of stock ground-tooth, spiral-bevel gears from Arrow Gear Co., Downers Grove, Ill. (arrowgear.com), cuts delivery to days and costs by 50% or more. It includes 53 gear combinations in sizes to 16-in. diameter and quality levels to Q13.

"The line targets manufacturers of power-transmission systems looking to reduce costs for prototype development and low-volume production," says Arrow CEO and Chairman, James J. Cervinka.

Blanks can be modified in about two weeks to fit specific gearboxes. Only gear teeth are carburized and hardened — as opposed to through hardening common for most stock gears — which simplifies machining. The use of special FEA software optimizes tooth contact patterns under fully loaded conditions to account for gearbox deflections.