Selecting Flat Washers, M4, in ISO 7089 / ISO 7093: the dimensional row from the standard plus the tools and hole sizes follow. Use them with the technical drawing below — the drawing redraws to the exact size you pick.
M4 Dimensional Row (ISO 7089 / ISO 7093)
| For bolt size | Inner diameter d1 min (mm) | Outer diameter d2 max (mm) | Thickness h (mm) | Reference standard |
|---|---|---|---|---|
| M4 | 4.3 | 9.0 | 0.8 | ISO 7089 |
Spanner & Drive for M4 Flat Washers
Drive geometry for M4 Flat Washers is given by the row above; match the tool to the listed values.
Common Applications for M4 Flat Washers
M4 Flat Washers are commonly specified for small electronics hardware and precision assemblies.
Installation Tips for M4 Flat Washers
- At M4 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
Mating Parts for M4
A M4 flat washer pairs with a M4 bolt/screw and matching M4 nut.
When to Step Up or Down from M4
When the joint preload approaches the proof load of M4 class 8.8, step up to M5 class 8.8 (or move to M4 class 10.9). When the joint is over-specified, M3 often saves weight and cost without losing the safety margin.