This page covers M12 Hex Bolts, Fine Pitch to ISO 8765: the full dimensional row, hole and tool sizes, proof-load data and typical applications. All values are taken from the governing standards (ISO 8765 together with ISO 273, ISO 724 and ISO 898-1 where applicable).
M12 Dimensional Row (ISO 8765)
| Size | Fine pitch (mm) | Width across flats s (mm) | Head height k (mm) | Stress area As (mmu00b2) | Common length range (mm) | Property class | Reference standard |
|---|---|---|---|---|---|---|---|
| M12 | 1.25 | 18.0 | 7.5 | 92.1 | 30~120 | 8.8 / 10.9 | ISO 8765 |
Spanner & Drive for M12 Hex Bolts, Fine Pitch
Drive geometry for M12 Hex Bolts, Fine Pitch is given by the row above; match the tool to the listed values.
Hole Sizes for M12
| Coarse-thread pitch (ISO 724) | 1.75 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 13.5 mm |
| Tapping drill, coarse thread | 10.2 mm |
Tightening Torque for M12
| Class 8.8 (dry, ~µ 0.125) | ≈ 85 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 120 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 145 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 M12
| Tensile stress area As (ISO 898-1) | 84.3 mm² |
|---|---|
| Proof load, class 8.8 | 49 kN |
| Proof load, class 10.9 | 70 kN |
| Proof load, class 12.9 | 82 kN |
| Min. ultimate tensile, class 8.8 | 67 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.
M12 Hex Bolts, Fine Pitch Weight
A steel M12 hex bolts, fine pitch at the listed 30,120 mm length weighs approximately 26,757 g each — about 26,757 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.
Mating Parts for M12
For M12, pair with a M12 hex nut (ISO 4032 / DIN 934) and, where used, a M12 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M12
When the joint preload approaches the proof load of M12 class 8.8, step up to M16 class 8.8 (or move to M12 class 10.9). When the joint is over-specified, M10 often saves weight and cost without losing the safety margin.
