Dimensional and assembly data for M20 All-Metal Lock Nuts to ISO 7042 / DIN 980. 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.
M20 Dimensional Row (ISO 7042 / DIN 980)
| Size | Pitch (mm) | Width across flats s (mm) | Nut height m (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| M20 | 2.5 | 30.0 | 21.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable |
Spanner & Drive for M20 All-Metal Lock Nuts
Drive geometry for M20 All-Metal Lock Nuts is given by the row above; match the tool to the listed values.
Common Applications for M20 All-Metal Lock Nuts
M20 All-Metal Lock Nuts are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M20 All-Metal Lock Nuts
- At M20 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
When to Step Up or Down from M20
When the joint preload approaches the proof load of M20 class 8.8, step up to M24 class 8.8 (or move to M20 class 10.9). When the joint is over-specified, M16 often saves weight and cost without losing the safety margin.