Ball chain sizes #2 to #30: ball (bead) diameter and the connector hole sizes (#3, #6, #10, #13 and more) — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/ball-chain-sizes/ (sheet CC BY 4.0) 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 Catalog version: 2026-10-20 Sizes: see table below - 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 - No file: with the pitch unpublished, a chain drawing would be invented.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. 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 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - 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) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/ball-chain - McMaster-Carr: Ball chain fittings (connectors, loop links, couplings) (free STEP/IGES per part, for your own design use; no redistribution) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/ball-chain-fittings - 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 — web — Retailer page; numbers only — https://mrlock.com/brand-index/lucky-line/key-tags-chains-and-rings/chain-and-connectors - Wikipedia: Ball chain — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Ball_chain No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned. API: https://xemstudio.com/api/geometry?object=ball-chain-sizes