Dimensional and assembly data for M3 Fender Washers to DIN 9021. Includes head size and width across flats, clearance-hole and tapping-drill diameters, tightening torque per property class, and the sizes to step up or down to when the joint requires it.
M3 Dimensional Row (DIN 9021)
| For bolt size | Inner diameter d1 min (mm) | Outer diameter d2 max (mm) | Thickness h (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| M3 | 3.2 | 9.0 | 0.8 | DIN 9021 / ISO 7093 | Oversized OD for bearing on soft materials |
Spanner & Drive for M3 Fender Washers
Drive geometry for M3 Fender Washers is given by the row above; match the tool to the listed values.
Common Applications for M3 Fender Washers
M3 Fender Washers are commonly specified for small electronics hardware and precision assemblies.
Installation Tips for M3 Fender Washers
- At M3 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
When to Step Up or Down from M3
When the joint preload approaches the proof load of M3 class 8.8, step up to M4 class 8.8 (or move to M3 class 10.9). When the joint is over-specified, M2 often saves weight and cost without losing the safety margin.