PCD HOLE LAYOUT GENERATOR
Bolt Circle Coordinate Generator
Turn a pitch circle diameter into a numbered hole table and a dimensioned preview, with machine-friendly CSV, SVG and DXF downloads.
CIRCLE GEOMETRY
Define the hole pattern
Angles use the mathematical convention: 0 degrees is on the positive X axis. Positive Y is up in the coordinate table.
PATTERN SUMMARY
- Angular spacing
- 60.000 deg
- Center-to-center chord
- 50.000 mm
- Hole count
- 6
- Pattern envelope
- 110.000 mm
NUMBERED OUTPUT
Coordinates and preview
| Hole | Angle | X | Y |
|---|
Coordinate method
Each hole is placed at an equal angular interval around the PCD. The center offset is added after the point is calculated. SVG uses an inverted screen Y axis internally, while the table and exported CSV keep positive Y pointing up.
x = center X + radius x cos(angle)Vertical coordinatey = center Y + radius x sin(angle)Adjacent-hole chord2 x radius x sin(pi / hole count)DXF output uses simple R12-compatible CIRCLE and POINT entities. Always check units and origin in the receiving CAD/CAM software before machining.
Shop-floor checks
- Confirm whether the drawing calls out PCD or radius; this calculator expects diameter.
- Verify the start-angle convention and clockwise direction used by the target machine.
- Include tool compensation, tolerances and workholding in the manufacturing setup, not in the nominal coordinate table.
- Measure a dry run or printed template before drilling a finished part.
Bolt circle questions
Are BCD and PCD the same here?
Yes. Bolt circle diameter (BCD) and pitch circle diameter (PCD) both describe the diameter through the centers of equally spaced holes.
Why is the first hole at positive X?
A start angle of 0 degrees follows the standard Cartesian convention. Enter 90 degrees to start at the top when positive Y is upward.
What does the DXF contain?
It contains the pitch circle, one circle for each hole and a point at each center. Dimensions and machining operations are intentionally left to your CAD/CAM workflow.