Hex head screws, M3–M8 (ISO 4017) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/hex-head-screws-metric/  (CC BY 4.0)
Basis: ISO 4017 (fully threaded hex head screws): width across flats s and head height k
Catalog version: 2026-10-20

Sizes: see table below
- Hex head: s across flats, k high, corners s × 1.155. A pocket that keeps the head from turning is drawn at s × k exactly (see Mating features), so a nut can be run down from the other side with one tool.
- Used in the two-bolt tri-clamp clamps: M5 × 30 in the 1½–4 in clamp halves, M8 in the 10 and 12 in clamps; each clamp half has the head pocket on one lug and a plain hole on the other.

thread  width_af_mm  corner_mm  head_height_mm  lengths_mm
M3  5.5  6.4  2.0  10, 16, 20
M4  7.0  8.1  2.8  12, 16, 20, 25
M5  8.0  9.2  3.5  16, 20, 25, 30, 40
M6  10.0  11.5  4.0  20, 25, 30, 40
M8  13.0  15.0  5.3  20, 25, 30, 40, 50

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- McMaster-Carr: Hex head screws (free STEP/IGES/STL per part, for your own design use; no redistribution) — STEP, IGES, STL, PDF — McMaster-Carr site terms: personal design use, no redistribution [verify license at link] — https://www.mcmaster.com/products/hex-head-screws/
- Wikipedia: Screw — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Screw

Free files (CC BY 4.0, Xem Studio; STEP + STL, 21 parts): https://xemstudio.com/files/hardware/hex-head-screws-metric/index.json
API: https://xemstudio.com/api/geometry?object=hex-head-screws-metric