Gear Measurement Over Pins Calculator & INTERNAL
Measurement Over Pins (or Measurement Over Wires) is a method for measuring and inspecting spur gears.
We built this gear measurement over pins calculator as a useful tool for designing and checking gears in our own shop, and want to share it with other gear enthusiasts around the world. This calculator ensures the tooth thickness on your spur gear is the right size using pins commonly found in your machine shop or easily ordered online.
How to Do Measurement Over Pins on a Gear
- Input your gear parameters
- Find the range of acceptable measurement pins
- Choose and input your pin size
- Calculate correct measurements to check your gear
- See results, formatted for easy copy and paste into Excel
- *For internal gears, use a negative tooth count (i.e. -20)
The default Manufacturing Profile Shift Coefficient is 0. Positive values result in thicker teeth, as if your cutting tool did not cut to a full depth, while negative values result in thinner teeth. Profile Shift Modification is also called Addendum Modifications and this is the design gateway for more contact ratio and a lower decibel product.
Note: Standard pins are not required (like the 1.728 or 1.92 series Van Keuren pins) - any set of quality high precision and known diameter pins will work that are within the range we calculate below.
Results conform to ANSI/AGMA 2002-D19 published in December 2019
Measurement over Pins (aka Measurement over Wires)
"Measurement over Pins" and "Measurement over Wires" are interchangeable terms when it comes to measuring gears, due to the many similarities between gears and threads. Using a precision pin allows for accurate and efficient measuring of gear teeth. Since a gear tooth is curved along its entire length (it follows the involute profile of a circle) it becomes incredibly difficult to measure. By introducing known-sized circular pins, the measurement becomes easy but requires some math. Fortunately, we've coded the math once so we (and you) won't need to touch it for each measurement. This calculator allows for measurement over pins of internal gears, external gears, even tooth counts, odd tooth counts, and prime tooth counts.
If you're interested in learning more about gearing, the NASA Gearing Guide
Gear Measurement, Design, and Production | Evolvent Design
We've been working with gears for decades and have done everything from gear design and specification, measurement and inspection, custom repairs, and small-to-mid sized production runs. We're a small shop but have extensive experience and the machinery for prototyping and small-scale production in-house. We've built tools like our Gear Measurement Over Pins Calculator to help us, and others, through every stage of the gear design process.
Looking to replace a broken gear, or design a new one from scratch? Want to understand more about Addendum Modification, Contact Ratio and the design of quieter gears? We can help - Contact Us today to get your product started