KEVOS® MAKEOS · Engineering
Bolt Circle Coordinates
Where are the centres of equally spaced holes?
Generate a coordinate table for an equally spaced bolt circle with a defined origin, start angle and direction.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Pitch circle diameter | mm | Hole-centre circle diameter from the drawing. |
| Hole count | holes | Equally spaced hole count. |
| Start angle from +X | ° | First hole angle; positive angles are anticlockwise. |
| Centre X | mm | Circle centre relative to the drawing or setup origin. |
| Centre Y | mm | Circle centre relative to the drawing or setup origin. |
| Numbering direction | choice | Direction in which successive hole numbers increase. |
Method and formulas
- Angular step = 360° ÷ hole count.
- X = centre X + radius × cos(angle); Y = centre Y + radius × sin(angle).
- Adjacent chord = 2 × radius × sin(π ÷ hole count). Example: four holes on a 100 mm circle centred at zero give (50,0), (0,50), (−50,0), (0,−50).
Limitations
- Coordinates are geometry only, not a CNC program.
- The drawing’s datum, view direction and tolerance system must be resolved separately.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- PCD
- hole coordinates
- bolt pattern
Who it is for
- Designers
- Toolmakers
- CNC programmers
What you get
- Angular spacing
- Adjacent centre chord
- Coordinate count
Interpreting the result
- Check one known hole and the coordinate origin before transferring positions to equipment.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 95–103, 692–695. Topic reference; no source tables or recommended settings are reproduced.
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