Bolt Hole Partial Arc Calculator

Calculate X/Y coordinates for holes distributed along a partial arc of a bolt circle. Specify the start angle and arc span.

Bolt Circle Diameter

Number of Holes

Start Angle (°)

Arc Span (°)

Formula:
X = (D/2) × cos(angle)
Y = (D/2) × sin(angle)
Holes are evenly distributed within the arc span starting from the start angle.

Why Partial Arc Patterns Matter

Not every bolt pattern is a full circle. Partial arcs appear on split-ring clamps, indexing plates, and sector flanges where holes only span part of the circumference. This calculator generates coordinates for any arc segment you define.

Define start angle, end angle, and hole count for any arc segment
Essential for split bearing housings, partial indexing fixtures, and arc-mounted components
Pair with coordinate rotation to position the arc anywhere on your workpiece

Bolt Hole Partial Arc Calculator

Why Partial Arc Patterns Matter

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