Flat washers, M2–M8 (ISO 7089) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/flat-washers-metric/  (CC BY 4.0)
Basis: ISO 7089 (normal series)
Catalog version: 2026-10-20

Sizes: see table below
- Inner diameter clears the screw; outer diameter is what a counterbore has to accommodate if the washer sits in it.

thread  id_mm  od_mm  thickness_mm
M2  2.2  5  0.3
M2.5  2.7  6  0.5
M3  3.2  7  0.5
M4  4.3  9  0.8
M5  5.3  10  1
M6  6.4  12  1.6
M8  8.4  16  1.6

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- McMaster-Carr: Washers (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/washers/
- Wikipedia: Washer (hardware) — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Washer_(hardware)

Free files (CC BY 4.0, Xem Studio; STEP + STL, 7 parts): https://xemstudio.com/files/hardware/flat-washers-metric/index.json
API: https://xemstudio.com/api/geometry?object=flat-washers-metric