The M30 size of Flat Washers is dimensioned by ISO 7089 / ISO 7093. The tables below give the dimensional row from the standard, the drill and spanner sizes that go with it, and the assembly torque per property class. The technical drawing on this page redraws to the exact values selected.
M30 Dimensional Row (ISO 7089 / ISO 7093)
| For bolt size | Inner diameter d1 min (mm) | Outer diameter d2 max (mm) | Thickness h (mm) | Reference standard |
|---|---|---|---|---|
| M30 | 31.0 | 56.0 | 4.0 | ISO 7089 |
Spanner & Drive for M30 Flat Washers
Drive geometry for M30 Flat Washers is given by the row above; match the tool to the listed values.
Common Applications for M30 Flat Washers
M30 Flat Washers are commonly specified for high-load load-spreading on structural joints.
Installation Tips for M30 Flat Washers
- At M30 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M30
A M30 flat washer pairs with a M30 bolt/screw and matching M30 nut.

