Dimensional and assembly data for M6 Carriage Bolts to DIN 603. Includes head size and width across flats, clearance-hole and tapping-drill diameters, tightening torque per property class, and the sizes to step up or down to when the joint requires it.
M6 Dimensional Row (DIN 603)
| Size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Square neck width (mm) | Square neck depth (mm) | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M6 | 1.0 | 16.0 | 3.5 | 6.0 | 3.0 | 16~120 | DIN 603 / ISO 8677 |
Spanner & Drive for M6 Carriage Bolts
Drive geometry for M6 Carriage Bolts is given by the row above; match the tool to the listed values.
Hole Sizes for M6
| Coarse-thread pitch (ISO 724) | 1 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 6.6 mm |
| Tapping drill, coarse thread | 5 mm |
Tightening Torque for M6
| Class 8.8 (dry, ~µ 0.125) | ≈ 10 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 14 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 17 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 M6
| Tensile stress area As (ISO 898-1) | 20.1 mm² |
|---|---|
| Proof load, class 8.8 | 12 kN |
| Proof load, class 10.9 | 17 kN |
| Proof load, class 12.9 | 19 kN |
| Min. ultimate tensile, class 8.8 | 16 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.
M6 Carriage Bolts Weight
A steel M6 carriage bolts at the listed 16,120 mm length weighs approximately 25,443 g each — about 25,443 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 M6 Carriage Bolts
M6 Carriage Bolts are commonly specified for general-purpose machinery, jigs, fixturing and light structural connections.
Mating Parts for M6
For M6, pair with a M6 hex nut (ISO 4032 / DIN 934) and, where used, a M6 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M6
When the joint preload approaches the proof load of M6 class 8.8, step up to M8 class 8.8 (or move to M6 class 10.9). When the joint is over-specified, M5 often saves weight and cost without losing the safety margin.