Generate X/Y coordinates for equally spaced holes on a bolt circle. Useful for CNC milling, drilling layouts, manual layout checks, and bolt pattern programming.
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Request a Proposal →Set your datum and start angle before programming. Verify whether the drawing uses diameter, radius, or existing hole coordinates.
A bolt circle is a circular pattern of equally spaced holes around a center point, usually defined by diameter and hole count.
Each hole is placed at a fixed angle increment. The X and Y values come from cosine and sine of each angle.
Yes, if your work offset, units, start angle, and center point match the setup. Always verify the first part.
Use this calculator to generate equally spaced hole coordinates around a center point for CNC drilling or milling.
Continue with closely related tools from the machining calculator library.
Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
Before you commit to a spec, it helps to know what the market pays for it. These are real, publicly listed factory prices — not a quotation, and not a guess.
We source the tool families below direct from vetted Chinese factories, matched to the material and tolerance you just worked out. Every batch ships with its material certificate and dimensional record.
LAYING OUT A BOLT CIRCLE? Hole patterns are the first thing a tool shop confirms back to you, so make them unambiguous. See what a Chinese tool shop needs from your drawing.
We source carbide cutting tools from China for job shops. We do not own a factory, which is why we can quote your drawing against two or three plants that actually run your material.
Cutting formulas with the units worked through · Speed and feed starting points for all six ISO material groups · How to read a carbide grade past its ISO code. 12 pages.
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