When you need Carriage Bolts in the M16 size, the controlling values come from DIN 603. This page lists them in one place — pitch, head geometry, tool size and the matching hole.
M16 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 |
|---|---|---|---|---|---|---|---|
| M16 | 2.0 | 40.0 | 9.0 | 16.0 | 8.0 | 40~300 | DIN 603 / ISO 8677 |
Spanner & Drive for M16 Carriage Bolts
Drive geometry for M16 Carriage Bolts is given by the row above; match the tool to the listed values.
Hole Sizes for M16
| Coarse-thread pitch (ISO 724) | 2 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 17.5 mm |
| Tapping drill, coarse thread | 14 mm |
Tightening Torque for M16
| Class 8.8 (dry, ~µ 0.125) | ≈ 210 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 295 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 355 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.
Common Applications for M16 Carriage Bolts
M16 Carriage Bolts are commonly specified for medium-duty structural connections, automotive sub-frames and equipment chassis.
Mating Parts for M16
For M16, pair with a M16 hex nut (ISO 4032 / DIN 934) and, where used, a M16 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M16
When the joint preload approaches the proof load of M16 class 8.8, step up to M20 class 8.8 (or move to M16 class 10.9). When the joint is over-specified, M12 often saves weight and cost without losing the safety margin.