Home Back

Bolt Circle Calculator

Bolt Circle Equation:

\[ position = r \times e^{i \times 2\pi / n} \]

inches

Unit Converter ▲

Unit Converter ▼

From: To:

1. What is Bolt Circle Calculation?

The Bolt Circle Calculator determines the precise position of bolts arranged in a circular pattern. This is essential in mechanical engineering, machining, and construction where multiple fasteners need to be equally spaced around a circle.

2. How Does the Calculator Work?

The calculator uses the bolt circle equation:

\[ position = r \times e^{i \times 2\pi / n} \]

Where:

Explanation: The equation calculates the complex number position of each bolt by distributing them equally around the circle at the given radius.

3. Importance of Bolt Circle Calculation

Details: Accurate bolt circle calculation ensures proper load distribution, prevents misalignment in rotating parts, and is crucial for flange designs and wheel patterns.

4. Using the Calculator

Tips: Enter the circle radius in inches, the bolt index (starting from 0), and the total number of bolts. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between bolt index and bolt count?
A: Bolt count is the total number of bolts, while bolt index identifies each individual bolt position (0 to count-1).

Q2: Can I use metric units instead of inches?
A: Yes, you can use any unit for radius as long as you're consistent (the output will be in the same unit).

Q3: How do I mark the positions in real life?
A: Use the X,Y coordinates to mark positions from the center point, or convert to polar coordinates (angle + distance).

Q4: What if my bolt count is very large?
A: The calculator works for any positive integer, but practical limitations depend on your drilling/machining capabilities.

Q5: Can this be used for non-bolt applications?
A: Yes, it works for any points equally spaced around a circle (e.g., gear teeth, sprocket holes, etc.).

Bolt Circle Calculator© - All Rights Reserved 2025