M18 Spring Lock Washers (ISO 7980 / DIN 127) are specified by thread size, length and head dimensions. The M18 row from the standard is reproduced below, followed by the drill sizes, spanner size and torque values used when installing this size.
M18 Dimensional Row (ISO 7980 / DIN 127)
| For bolt size | Inner diameter d1 min (mm) | Outer diameter d2 max (mm) | Width b (mm) | Thickness s (mm) | Reference standard |
|---|---|---|---|---|---|
| M18 | 18.2 | 29.4 | 9.0 | 3.5 | ISO 7980 / DIN 127 |
Spanner & Drive for M18 Spring Lock Washers
Drive geometry for M18 Spring Lock Washers is given by the row above; match the tool to the listed values.
Common Applications for M18 Spring Lock Washers
M18 Spring Lock Washers are commonly specified for high-load load-spreading on structural joints.
Installation Tips for M18 Spring Lock Washers
- At M18 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 M18
A M18 flat washer pairs with a M18 bolt/screw and matching M18 nut.

