M24 Stud Bolt, Double-End (GB/T 15389 / DIN 938) are specified by thread size, length and head dimensions. The M24 row from the standard is reproduced below, followed by the drill sizes, spanner size and torque values used when installing this size.
M24 Dimensional Row (GB/T 15389 / DIN 938)
| Thread size | Pitch (mm) | Length L (mm) | Engagement depth bm (mm) | Material | Reference standard |
|---|---|---|---|---|---|
| M24 | 3.0 | 200 | 36 | Cl. 8.8 alloy steel | DIN 939 / GB/T 901 |
Spanner & Drive for M24 Stud Bolt, Double-End — GB/T 15389 / DIN 938 (Series 092)
Drive geometry for M24 Stud Bolt, Double-End — GB/T 15389 / DIN 938 (Series 092) is given by the row above; match the tool to the listed values.
Hole Sizes for M24
| Coarse-thread pitch (ISO 724) | 3 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 26 mm |
| Tapping drill, coarse thread | 21 mm |
Tightening Torque for M24
| Class 8.8 (dry, ~µ 0.125) | ≈ 710 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 1000 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 1200 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 M24
| Tensile stress area As (ISO 898-1) | 353 mm² |
|---|---|
| Proof load, class 8.8 | 212 kN |
| Proof load, class 10.9 | 293 kN |
| Proof load, class 12.9 | 342 kN |
| Min. ultimate tensile, class 8.8 | 282 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.
M24 Stud Bolt, Double-End — GB/T 15389 / DIN 938 (Series 092) Weight
A steel M24 stud bolt, double-end at the listed 200 mm length weighs approximately 710 g each — about 710 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 M24 Stud Bolt, Double-End — GB/T 15389 / DIN 938 (Series 092)
M24 Stud Bolt, Double-End — GB/T 15389 / DIN 938 (Series 092) are commonly specified for structural steelwork, heavy machinery foundations and large flange joints.
Installation Tips for M24 Stud Bolt, Double-End — GB/T 15389 / DIN 938 (Series 092)
- At M24 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 M24
For M24, pair with a M24 hex nut (ISO 4032 / DIN 934) and, where used, a M24 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.