Diametral Pitch vs. Pitch Diameter

Reading the terms “diametral pitch” and “pitch diameter” can get confusing. The important thing to note about these two terms is that they refer to two very different things. To better understand both of these terms, read the information below. It will provide additional insight on diametral pitch vs. pitch diameter, so there is no confusion going forward.

The Pitch Diameter

When one refers to the pitch diameter, they may also call it the effective diameter. Both of these terms represent the diameter of the pitch circle. In order to calculate or find the pitch diameter, one must directly determine the distance between the center and the number of teeth. This term is sometimes indicated by the letters PD.

What Does Diametral Pitch Mean?

This term specifically refers to the number of teeth in the gear for each inch of the pitch diameter. Basically, this term refers to the overall is the size of the gear tooth. It is the diametral pitch that helps create all gears. This term is often identified using the letters DP.

Looking at the information above on diametral pitch vs. pitch diameter helps better explain how these two terms are not the same, even if they appear extremely similar to the untrained eye. These definitions explain how the terms are different and what each of them represents in regard to all different types of gears. It is our hope that this information provides you with the foundation of knowledge you need to better understand the inner workings of gears.

Here at Blaz-Man Gear Inc. – Power Transmission Group, we want to do our part to help you attain the gear knowledge you need while also providing you with wonderful gear-related services. Whether you need custom gearboxes or internal spline manufacturing, we do it all. Take a look at our website and give us a call today to discuss how we can help you get exactly what you need!


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