For Hex Slotted Castle Nut (Type 2) — GB/T 6180 / ISO 7036 (Series 050), the M20 thread sits in the heavy-duty range of the catalog and is one of the most-asked hex slotted castle nut (type 2) — gb/t 6180 / iso 7036 (series 050) in this family. The dimensional and assembly data follow.
M20 Dimensional Row (GB/T 6180 / ISO 7036)
| Size | Pitch (mm) | Width across flats s (mm) | Width across corners e (mm) | Total height m (mm) | Slot width (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M20 | 2.5 | 30.0 | 33.53 | 24.0 | 5.5 | ISO 7036 / GB/T 6180 |
Spanner & Drive for M20 Hex Slotted Castle Nut (Type 2) — GB/T 6180 / ISO 7036 (Series 050)
Drive geometry for M20 Hex Slotted Castle Nut (Type 2) — GB/T 6180 / ISO 7036 (Series 050) is given by the row above; match the tool to the listed values.
Common Applications for M20 Hex Slotted Castle Nut (Type 2) — GB/T 6180 / ISO 7036 (Series 050)
M20 Hex Slotted Castle Nut (Type 2) — GB/T 6180 / ISO 7036 (Series 050) are commonly specified for structural joints, flange connections and heavy equipment foundations.
Installation Tips for M20 Hex Slotted Castle Nut (Type 2) — GB/T 6180 / ISO 7036 (Series 050)
- 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.
Mating Parts for M20
Pair M20 with the matching M20 bolt or screw, plus a M20 flat washer where required to distribute load on softer materials.
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.