Bolt Circle & Hole Pattern Coordinate Generator Community
Questions, answers and tips from people who use the Bolt Circle & Hole Pattern Coordinate Generator. Hole coordinates for bolt circles, rows and grids with DXF, SVG and G-code export.
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This page shows only real posts from real people, so it starts empty. The guide below has the questions people most often have about the Bolt Circle & Hole Pattern Coordinate Generator. Pick one to start a thread, or write your own.
From the tool guide: common questions about Bolt Circle & Hole Pattern Coordinate Generator
The items below are not posts by community members. They come from the written guide for this tool and are here to get a conversation started. Use “Ask a follow-up” to open a thread about any of them.
What is PCD?
Pitch circle diameter: the diameter of the circle through the hole centres.
From the tool guide Ask a follow-upHow is chord length calculated?
2 × R × sin(π / N) for N holes on a circle of radius R.
From the tool guide Ask a follow-upIs the G-code universal?
It uses standard G81 for Fanuc-like controllers (also GRBL variants with canned cycles).
From the tool guide Ask a follow-upWhat this tool does
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.
How to use it, step by step
- Choose bolt circle, row or grid.
- Enter count, diameters or spacings.
- Check the preview and coordinates.
- Download DXF/SVG, copy CSV or export the drilling G-code.
Tips from the guide
- Use the across-holes measurement to verify a drilled circle.
- For even hole counts measure opposite holes; for odd counts use the chord.
- Use a DXF import to place holes in CAD at exact positions.
- Check the G-code on your machine's dry-run before cutting.
Common mistakes to avoid
- Mixing up PCD and hole-circle radius.
- Forgetting the start angle on a flange with a keyed position.
- Running generated G-code without checking depth and safe Z.
Who uses it
- Machinists and CNC users. Drilling coordinates and a ready G81 program.
- CAD users. Check a bolt circle against calculated coordinates.
- Makers. Design flanges and mounts accurately.
How to ask a question people can answer
A good thread on the Bolt Circle & Hole Pattern Coordinate Generator saves everyone time. Start with a title that names the exact problem, such as the input you used, the result you expected and the result you got. A title like “Not working” is hard to answer, while a title with the specifics gets replies quickly.
- Say what you tried. List the steps you followed and any settings you changed, so replies do not repeat what you already did.
- Share a small example. A short sample input and the output you saw is worth more than a long description. Remove anything private first.
- Mention your setup. Your device, browser and whether you are on a phone or a computer can explain many odd results.
- One question per thread. Separate topics get clearer answers and are easier to find later with the search box above.
- Come back and reply. If a suggestion worked, say so and upvote it, and if you found the fix yourself, post it for the next person.
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