Diametrical pitch is defined as the number of teeth per inch of which feature?

Diametrical pitch is defined as the number of teeth per inch of which feature?

• A. Pitch Circle Length
• B. Pitch Circle Diameter
• C. Base Circle Diameter
• D. Tooth Crest Radius

Answer: (B)

Diametrical pitch is the number of teeth per inch of the pitch diameter—the imaginary circle where the teeth effectively engage. The pitch diameter (also called the pitch circle diameter) defines that circle, so diametrical pitch = (number of teeth) / (pitch diameter in inches). This is why gears that mesh must share the same diametral pitch, ensuring the teeth space and size line up along the pitch circles. The base circle diameter is related to involute tooth geometry but doesn’t determine teeth per inch, and the crest radius is simply the outer tooth radius, not used to define diametral pitch.

Diametrical pitch is the number of teeth per inch of the pitch diameter—the imaginary circle where the teeth effectively engage. The pitch diameter (also called the pitch circle diameter) defines that circle, so diametrical pitch = (number of teeth) / (pitch diameter in inches). This is why gears that mesh must share the same diametral pitch, ensuring the teeth space and size line up along the pitch circles. The base circle diameter is related to involute tooth geometry but doesn’t determine teeth per inch, and the crest radius is simply the outer tooth radius, not used to define diametral pitch.