Site Last Updated 9/21/14
3 Wire Thread Pitch Diameter Measuring
A very common way to measure the pitch diameter of 60° V screw threads is with the 3 wire thread measuring method. In this thread measuring method a measurement is taken across 3 predefined pins or “wires” placed in the thread v usually with a micrometer or to a less accurate degree with calipers. Once the measurement is taken an accurate pitch diameter can be determined by subtracting a “constant” from the measured dimension to obtain the actual thread pitch diameter.
Measurement across wires using a micrometer.
Actual thread pitch diameter determined by subtracting the constant from the measurement taken across the 3 thread wires.
Wire size used in the 3 wire thread measuring method.
Just Added to Web Machinist! 3 Wire Thread Measuring Calculator”. Quickly calculate dimensions when using the 3 wire thread pitch measuring method for both inch and metric threads.
The Web Machinist 3 Wire Thread Measuring Calculator above is available in the Web Machinist software program seen below:
The chart below lists the Wire Size and Constant for measuring Inch 60° V threads using the 3 wire thread measuring system:
The chart below lists the Wire Size and Constant for measuring Metric 60° V threads using the 3 wire thread measuring system:
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