1. What is Pitch Circle Diameter?

Pitch Circle Diameter (PCD) is the diameter of the circle which passes through the center of all the bolts or studs in a circular pattern. It is a critical measurement in mechanical engineering for designing and manufacturing components with bolt circles.

2. How Does the Calculator Work?

The calculator uses the PCD formula:

Where:

• \( Bolt\ Spacing \) — Distance between adjacent bolts (mm)
• \( n \) — Number of bolts in the circle
• \( 180^\circ / n \) — Angle between adjacent bolts

Explanation: The formula calculates the diameter of the circle that passes through the center of all bolts based on the spacing between adjacent bolts and the number of bolts.

3. Importance of PCD Calculation

Details: Accurate PCD calculation is essential for proper fitting of components, ensuring bolt patterns match between mating parts, and preventing misalignment in mechanical assemblies.

4. Using the Calculator

Tips: Enter bolt spacing in millimeters and the number of bolts. The number of bolts must be at least 2, and bolt spacing must be a positive value.

5. Frequently Asked Questions (FAQ)

Q1: What is bolt spacing measured between?
A: Bolt spacing is measured as the straight-line distance between the centers of two adjacent bolts in the circular pattern.

Q2: Can this calculator be used for any number of bolts?
A: Yes, the formula works for any number of bolts from 2 upwards, though practical applications typically use 3 or more bolts.

Q3: How accurate is this calculation?
A: The calculation is mathematically precise. Accuracy in real applications depends on precise measurement of bolt spacing.

Q4: Does this work for both metric and imperial units?
A: The calculator uses millimeters, but you can use any unit as long as you're consistent (the result will be in the same unit).

Q5: What are common applications of PCD calculations?
A: PCD calculations are used in wheel hubs, flanges, gears, pulleys, and any circular bolt pattern in mechanical design.