A hex flange bolt in M16: this guide pulls the row from the standard, adds the assembly numbers an engineer actually uses, and links you straight to a quote.
M16 Dimensional Row (ISO 1665 / DIN 6921)
| Size | Pitch (mm) | Flange diameter dc (mm) | Head height k (mm) | Width across flats s (mm) | Reference standard |
|---|---|---|---|---|---|
| M16 | 2.0 | 34.5 | 14.1 | 24.0 | ISO 1665 / DIN 6921 |
Spanner & Drive for M16 Hex Flange Bolts
M16 Hex Flange Bolts have a width across flats of 24.0 mm — fit a 24.0 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 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 Hex Flange Bolts
M16 Hex Flange Bolts are commonly specified for medium-duty structural connections, automotive sub-frames and equipment chassis.
Installation Tips for M16 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.
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.