Square nuts, DIN 557: M5–M20 width across flats, thickness, corner distance + 8 envelope files — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/square-nuts-din-557/ (sheet CC BY 4.0) Basis: fasten.it's DIN 557 table (M5 to M16, 01/1994) and CDE Fasteners' sheet (M5 to M20); they agree on thickness and corners, and fasten.it prints two variants for M10 and M12; eight envelope files Catalog version: 2026-10-20 Overall (mm): length 24.0, width 24.0, height 13.0 - Columns (mm): d thread, P pitch, s width across flats (square side; nominal = max), e max across corners, m nominal thickness (= max), mw min, dw min (the washer-face diameter as printed, all as fasten.it labels them). CDE's columns F, G, H are the width across the square, the width across corners (min) and the thickness. - Two variants: fasten.it prints two rows each for M10 (s 16 with e 22.6, and s 17 with e 24) and M12 (s 18 / 25.4 and s 19 / 26.9), and does not say why. CDE prints only the larger one (M10 17 / 24, M12 19 / 26.9). The files carry both for M10 and M12 (second variant marked -v2). M5, M6, M8 and M16 agree in both sources; M20 is CDE only (30 / 42.4 / 16). - Files are Xem-drawn envelopes: a square s × s of thickness m with a plain bore at the thread major diameter. The e value is the printed corner distance of the chamfered nut; the file's square corners are slightly further out (s·√2), as the file note says. Chamfer and thread are not modelled. For a captive-nut pocket of a square nut, the width across flats and the thickness are the numbers needed. - Nuts for square-head bolts and slide-in T-nuts: slide-in-t-nuts, drop-in-t-nuts. McMaster-Carr's square-nut pages found by search are inch; they are linked, not copied. No metric (DIN 557) McMaster category URL was returned. thread P (mm) s (square side) e max (across corners) m (thickness) mw min dw min CDE F / G / H M5 0.8 8 11.3 4 2.5 6.7 8 / 11.3 / 4 M6 1 10 14.1 5 3.2 8.7 10 / 14.1 / 5 M8 1.25 13 18.4 6.5 4.1 11.5 13 / 18.4 / 6.5 M10 1.5 16 22.6 8 5.2 14.5 — M10 (second variant) 1.5 17 24 8 5.2 15.5 17 / 24 / 8 M12 1.75 18 25.4 10 6.6 16.5 — M12 (second variant) 1.75 19 26.9 10 6.6 17.2 19 / 26.9 / 10 M16 2 24 33.9 13 8.6 22 24 / 33.9 / 13 M20 2.5 — — — — — 30 / 42.4 / 16 (CDE only) Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - fasten.it: DIN 557 square nuts, product grade C (01/1994): d, P, dw min, e max, m, mw min, s, M5 to M16 incl. two variants for M10 and M12 — web — Reference page; numbers only — https://fasten.it/en/norms/norm/din_557 - CDE Fasteners: DIN 557 square nuts: F width across square, G across corners (min), H thickness, M5 to M20 — web — Maker data sheet; numbers only — https://cdefasteners.com/sites/default/files/product-specs/metd557.pdf - McMaster-Carr: Machine screw square nuts (inch) (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/machine-screw-square-nuts - McMaster-Carr: Round-top square nuts (inch) (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/products/round-top-square-nuts/ Free files (CC BY 4.0, Xem Studio; STEP + STL, 8 parts): https://xemstudio.com/files/hardware/square-nuts-din-557/index.json API: https://xemstudio.com/api/geometry?object=square-nuts-din-557