Meet the Bolt Circle & Hole Pattern Coordinate
Generate hole coordinates for bolt circles (PCD), linear rows and grids with chord distances, wheel PCD presets, a preview, CSV copy and DXF.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
What is the Bolt Circle & Hole Pattern Coordinate?
A bolt circle is a set of equally spaced holes on a circle — wheel hubs, flanges, pulleys, motor mounts. Enter the number of holes, the bolt-circle (pitch circle) diameter, a start angle and the centre, and the generator returns the exact X/Y coordinates and angle of every hole, the chord distance between neighbouring holes and the across-holes distance used for inspection. Presets fill common wheel patterns such as 5×114.3, 5×100, 4×100, 6×139.7 and the NEMA 17 4×31 mount.
Linear rows and rectangular grids (with rotation and optional centring) are covered too. A live preview draws the holes and the pitch circle; the coordinates can be copied as CSV, downloaded as a DXF or SVG with circles of your hole diameter, or exported as G-code with a G81 canned drilling cycle with your depth, feed and safe height — ready for a CNC mill or drill press with DRO.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Any count, PCD, start angle and centre; common wheel and flange patterns.
Linear spacing, grid spacing and rotation.
Chord between holes and across-holes dimensions.
G81 drill cycle with depth, feed and safe Z.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
How it compares
A plain look at this tool next to the usual alternative.
| This engineering calculator | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
What is PCD?
Pitch circle diameter: the diameter of the circle through the hole centres.
How is chord length calculated?
2 × R × sin(π / N) for N holes on a circle of radius R.
Is the G-code universal?
It uses standard G81 for Fanuc-like controllers (also GRBL variants with canned cycles).
Can I rotate a grid?
Yes — set the pattern rotation angle.
How do I use the Bolt Circle & Hole Pattern Coordinate?
1. Choose bolt circle, row or grid. 2. Enter count, diameters or spacings. 3. Check the preview and coordinates. 4. Download DXF/SVG, copy CSV or export the drilling G-code.
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Hole coordinates for bolt circles, rows and grids with DXF, SVG and G-code export. Free to use.
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