PangPang ToolsPCD 200 mm; 8 equally spaced holes; first angle 0°
Adjacent spacing 76.536686 mm; first hole X 100 mm, Y 0 mm; 45° stepEight holes form a 45° pitch; the straight chord between adjacent centres is 200 × sin(22.5°), not the longer arc distance.
Area & Drawings
Bolt circle PCD and hole position calculator
Bolt patterns with equally spaced holes can be laid out on a pitch circle diameter (PCD). This calculator uses radius = PCD ÷ 2, angular pitch = 360° ÷ hole count and adjacent-hole chord length = PCD × sin(180° ÷ hole count). It also gives the first hole's X and Y coordinates from a user-selected starting angle, using the circle centre as (0,0). It does not verify bolt strength, edge distances or structural suitability.
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Result
Worked examples
PCD 120 mm; 6 equally spaced holes; first angle 90°
Adjacent spacing 60 mm; first hole X ≈ 0 mm, Y 60 mm; 60° stepWith a 60 mm radius and a 90° start, the first hole is on the positive Y-axis.
Questions & answers
Is adjacent spacing an arc distance or a straight hole-centre distance?
It is a straight chord between adjacent hole centres. The arc along the circle is longer except for a vanishingly small angle.
Does the calculation show every hole coordinate?
The current output shows the first hole's XY coordinates and the common angular step. To derive other positions, add multiples of the step angle and apply the same polar-coordinate formula.