M18 Studs & Threaded Rods (DIN 939 / DIN 975) 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 (DIN 939 / DIN 975)
| Thread size | Pitch (mm) | Point type | Common lengths (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| M18 | 2.5 | M18 | 40~300 | DIN 939 | Stud, equal thread both ends |
Spanner & Drive for M18 Studs & Threaded Rods
Drive geometry for M18 Studs & Threaded Rods is given by the row above; match the tool to the listed values.
Hole Sizes for M18
| Coarse-thread pitch (ISO 724) | 2.5 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 20 mm |
| Tapping drill, coarse thread | 15.5 mm |
Tightening Torque for M18
| Class 8.8 (dry, ~µ 0.125) | ≈ 290 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 405 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 485 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M18
| Tensile stress area As (ISO 898-1) | 192 mm² |
|---|---|
| Proof load, class 8.8 | 115 kN |
| Proof load, class 10.9 | 159 kN |
| Proof load, class 12.9 | 186 kN |
| Min. ultimate tensile, class 8.8 | 154 kN |
Proof load = stress area × proof stress per ISO 898-1. Design joints so the working preload stays below the proof load of the selected class.
M18 Studs & Threaded Rods Weight
A steel M18 studs & threaded rods at the listed 40,300 mm length weighs approximately 80,503 g each — about 80,503 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³). Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.
Common Applications for M18 Studs & Threaded Rods
M18 Studs & Threaded Rods are commonly specified for structural steelwork, heavy machinery foundations and large flange joints.
Installation Tips for M18 Studs & Threaded Rods
- 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
For M18, pair with a M18 hex nut (ISO 4032 / DIN 934) and, where used, a M18 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.