Home
Back
Pitch Diameter Formula:
| From: | To: |
The Pitch Diameter of External Thread is the simple effective diameter of external screw thread, approximately halfway between the major and minor diameters. It represents the diameter where the width of the thread and the space between threads are equal.
The calculator uses the formula:
Where:
Explanation: The formula calculates the pitch diameter by subtracting 75% of the fundamental triangle height from the major diameter of the external thread.
Details: Accurate pitch diameter calculation is crucial for proper thread fitting, ensuring mechanical strength, and maintaining dimensional accuracy in threaded connections and fasteners.
Tips: Enter the major diameter and height of fundamental triangle in meters. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What is the significance of the 0.75 factor in the formula?
A: The 0.75 factor represents the relationship between the fundamental triangle height and the actual thread dimensions, accounting for the specific geometry of standard thread forms.
Q2: How does pitch diameter differ from major and minor diameters?
A: Major diameter is the largest diameter of the thread, minor diameter is the smallest, and pitch diameter is the theoretical diameter where thread width equals space width.
Q3: Why is pitch diameter important in thread measurement?
A: Pitch diameter determines the fit between mating threads and is critical for ensuring proper thread engagement and mechanical performance.
Q4: Can this formula be used for all thread types?
A: This specific formula is primarily used for standard metric and unified thread forms. Other thread types may require different calculation methods.
Q5: What units should be used for input values?
A: The calculator uses meters for both input values, but you can convert from other units (mm, inches) by applying appropriate conversion factors before input.