M8 Stud / Threaded Rod are manufactured to ISO / DIN with a coarse thread pitch of 1.25 mm. This page lists the controlling dimensions for the M8 size — head geometry, width across flats, matching spanner size — together with the clearance hole, tapping drill and tightening torque used at assembly.
M8 Dimensional Row (ISO / DIN)
| Thread size | Pitch (mm) | Length L (mm) | Engagement depth bm (mm) | Material | Reference standard |
|---|---|---|---|---|---|
| M8 | 1.25 | 60 | 10 | Cl. 8.8 alloy steel | DIN 939 / GB/T 901 |
Spanner & Drive for M8 Stud / Threaded Rod — ISO / DIN (Series 154)
Drive geometry for M8 Stud / Threaded Rod — ISO / DIN (Series 154) is given by the row above; match the tool to the listed values.
Hole Sizes for M8
| Coarse-thread pitch (ISO 724) | 1.25 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 9 mm |
| Tapping drill, coarse thread | 6.8 mm |
Tightening Torque for M8
| Class 8.8 (dry, ~µ 0.125) | ≈ 25 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 35 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 41 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 M8
| Tensile stress area As (ISO 898-1) | 36.6 mm² |
|---|---|
| Proof load, class 8.8 | 21 kN |
| Proof load, class 10.9 | 30 kN |
| Proof load, class 12.9 | 36 kN |
| Min. ultimate tensile, class 8.8 | 29 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.
M8 Stud / Threaded Rod — ISO / DIN (Series 154) Weight
A steel M8 stud / threaded rod at the listed 60 mm length weighs approximately 24 g each — about 24 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 M8 Stud / Threaded Rod — ISO / DIN (Series 154)
M8 Stud / Threaded Rod — ISO / DIN (Series 154) are commonly specified for general-purpose machinery, jigs, fixturing and light structural connections.
Mating Parts for M8
For M8, pair with a M8 hex nut (ISO 4032 / DIN 934) and, where used, a M8 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M8
When the joint preload approaches the proof load of M8 class 8.8, step up to M10 class 8.8 (or move to M8 class 10.9). When the joint is over-specified, M6 often saves weight and cost without losing the safety margin.