The Boston Gear YD72 Spur Gear is a cast iron spur gear designed for parallel-shaft power transmission, featuring 72 teeth, a diametral pitch of 12 DP, and a 20-degree pressure angle. Official listings and Boston Gear's catalog materials consistently present the YD72 as a 12 DP, 20 PA, 72-tooth cast-iron spur gear, aligned with standard stock gears for parallel-shaft layouts. In operation, spur gears are used to transmit motion and power between parallel shafts, and the YD72 is intended for such gear-train configurations in general mechanical power transmission systems.
