Dimensional and assembly data for M10 Hex Flange Bolts to ISO 1665 / DIN 6921. 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.
M10 Dimensional Row (ISO 1665 / DIN 6921)
| Size | Pitch (mm) | Flange diameter dc (mm) | Head height k (mm) | Width across flats s (mm) | Reference standard |
|---|---|---|---|---|---|
| M10 | 1.5 | 21.8 | 8.9 | 15.0 | ISO 1665 / DIN 6921 |
Spanner & Drive for M10 Hex Flange Bolts
M10 Hex Flange Bolts have a width across flats of 15.0 mm — fit a 15.0 mm open-ended spanner or socket. Use a 6-point socket for tight clearances and to reduce rounding; for repeated assembly choose a torque wrench so the joint preload is repeatable.
Hole Sizes for M10
| Coarse-thread pitch (ISO 724) | 1.5 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 11 mm |
| Tapping drill, coarse thread | 8.5 mm |
Tightening Torque for M10
| Class 8.8 (dry, ~µ 0.125) | ≈ 49 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 69 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 83 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 M10
| Tensile stress area As (ISO 898-1) | 58 mm² |
|---|---|
| Proof load, class 8.8 | 34 kN |
| Proof load, class 10.9 | 48 kN |
| Proof load, class 12.9 | 56 kN |
| Min. ultimate tensile, class 8.8 | 46 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.
Common Applications for M10 Hex Flange Bolts
M10 Hex Flange Bolts are commonly specified for general-purpose machinery, jigs, fixturing and light structural connections.
Installation Tips for M10 Hex Flange Bolts
- Use a 6-point socket where access allows — 12-point sockets are more prone to rounding the corners on smaller sizes.
- On flanged or serrated variants, do NOT add a separate flat washer — the flange already spreads the load and the washer can defeat the locking serrations.
When to Step Up or Down from M10
When the joint preload approaches the proof load of M10 class 8.8, step up to M12 class 8.8 (or move to M10 class 10.9). When the joint is over-specified, M8 often saves weight and cost without losing the safety margin.