包括20至120径节的正齿轮和斜齿轮，齿比为20度压力角，有7个或更多齿。所示的齿比也可能适用于直径间距小于120的齿轮设计。

Includes spur and helical gearing of 20 through 120 diametral pitch with tooth proportions of 20 degree pressure angle and having 7 or more teeth. Tooth proportions shown may also be suitable for gear designs of finer than 120 diametral pitch.