Bolt Circle Calculator
An essential layout tool for fabricators and machinists. Instantly calculate the X-Y coordinates for drilling holes on a pitch circle diameter (PCD).
Precision in Fabrication: The Bolt Circle
A bolt circle, or Pitch Circle Diameter (PCD), is a common feature in mechanical design, used for everything from pipe flanges and gears to wheel hubs and engine components. It's an imaginary circle on which the centers of a pattern of holes are located. For these components to fit together correctly, the holes must be drilled with extreme precision. This calculator eliminates manual calculations and potential errors, providing machinists and fabricators with the exact X-Y coordinates needed for layout or CNC programming.
The Trigonometry Behind the Coordinates
The calculation is a straightforward application of trigonometry for a circle centered at (0,0).
- Angle Step: The angle between each hole is found by dividing 360 degrees by the number of holes: `360 / N`.
- Coordinate Calculation: For each hole, its X and Y coordinates are found using the cosine and sine of its angle, respectively, multiplied by the circle's radius (Diameter / 2).
- `X = radius * cos(angle)`
- `Y = radius * sin(angle)`
This tool performs these calculations for each hole in the pattern, giving you a ready-to-use table of coordinates.