# Ball chain sizes #2 to #30: ball (bead) diameter and the connector hole sizes (#3, #6, #10, #13 and more)

> What are the ball sizes of #3, #6, #10 and #13 ball chain, and which connector fits?

- Category: Mechanisms › Mechanism parts
- Kind: Standard part
- Basis: McMaster-Carr's bead-chain tables (trade size, bead diameter, link mounting-hole diameters) cross-checked against Lucky Line's #3, #6, #8, #10 listings; numbers only
- Page: https://xemstudio.com/objects/ball-chain-sizes/ · JSON: https://xemstudio.com/api/geometry?object=ball-chain-sizes · Plain text: https://xemstudio.com/objects/ball-chain-sizes/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no tolerance added.

## Notes

- Ball chain (also bead chain) is sold by a trade size number. McMaster-Carr prints the bead diameter per size: #2 and #3 3/32 in, #6 1/8 in, #8 5/32 in, #10 3/16 in, #13 1/4 in, #20 3/8 in, #30 1/2 in. Lucky Line's listings agree for #3 (3/32), #6 (1/8), #8 (5/32) and #10 (3/16), and Wikipedia calls #3 a 2.4 mm steel ball chain (3/32 in = 2.38 mm). An Eaton lamp-chain listing gives 0.13 in for #6 without saying whether that is the ball or the chain, so it is not used.
- Connectors are matched by trade size: McMaster sells connectors, loop links and couplings by the same size number, and Lucky Line's listing says the connector 'matches' the chain size; neither printed a size-by-size chart of connector body dimensions. The hole diameters in the table are McMaster's mounting-hole diameters for its screw-mount and push-mount links, as printed, and vary by material and finish.
- Ball spacing (pitch) is not given in any source read, so it is not on this page; neither are the chain's overall width or the connector body. McMaster also lists bead-chain loop links (4, 6, 8 and 12 in), lanyards (3 to 18 in, 3/16 in bead) and tag rings (ID 1-7/16 to 3-7/8 in, 1/8 in bead); not tabulated here.
- No file: with the pitch unpublished, a chain drawing would be invented. McMaster-Carr sells ball chain and fittings with per-part STEP; linked, not copied.

## Sizes

| trade size | bead diameter | screw-mount link hole (in) | push-mount link hole (in) | source |
|---|---|---|---|---|
| #2 | 3/32 in (2.38 mm, computed) | not listed | 0.13 (nickel-plated brass) in | McMaster-Carr |
| #3 | 3/32 in (2.38 mm, computed) | 0.13 in | 0.13 in | McMaster-Carr; Lucky Line agrees |
| #6 | 1/8 in (3.17 mm, computed) | 0.13 in | 0.16 in | McMaster-Carr; Lucky Line agrees |
| #8 | 5/32 in (3.97 mm, computed) | 0.19 (nickel-plated brass) in | 0.22 in | McMaster-Carr; Lucky Line agrees |
| #10 | 3/16 in (4.76 mm, computed) | 0.19 in | 0.22 in | McMaster-Carr; Lucky Line agrees |
| #13 | 1/4 in (6.35 mm, computed) | 0.19 in | 0.31 (nickel-plated brass) in | McMaster-Carr |
| #20 | 3/8 in (9.52 mm, computed) | 0.26 (nickel-plated brass) in | not listed | McMaster-Carr |
| #30 | 1/2 in (12.70 mm, computed) | not listed | not listed | McMaster-Carr |

## Where the files are

- McMaster-Carr: [Ball (bead) chain, trade sizes 3 to 30, with bead diameter and connector hole diameters (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/ball-chain) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)
- McMaster-Carr: [Ball chain fittings (connectors, loop links, couplings) (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/ball-chain-fittings) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)
- Lucky Line (listed by Mr. Lock): [Ball chain #3, #6, #8, #10: ball diameter per size (3/32, 1/8, 5/32, 3/16 in); connectors and couplings sold by size](https://mrlock.com/brand-index/lucky-line/key-tags-chains-and-rings/chain-and-connectors) — web — Retailer page; numbers only
- Wikipedia: [Ball chain](https://en.wikipedia.org/wiki/Ball_chain) — web — CC BY-SA 4.0 (text)

## Questions

**What size is #6 ball chain?**

Bead diameter 1/8 in (3.18 mm), per McMaster-Carr and Lucky Line. Its connectors are the #6 ones; McMaster's screw-mount link hole for #6 is 0.13 in, push-mount 0.16 in.

**What is the ball size of #10 and #13 ball chain?**

#10 is 3/16 in (4.76 mm) and #13 is 1/4 in (6.35 mm), per McMaster-Carr. No source read gave the spacing between balls.

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