# M14 bolt torque

Tighten an M14 × 2 class 8.8 bolt to 141 N·m (104 ft-lb) with dry threads, or 105 N·m when lubricated. Class 10.9 takes 201 N·m and class 12.9 takes 235 N·m.

## M14 × 2 torque by property class

| Property class | Dry torque (K 0.20) | Lubricated (K 0.15) | Clamp load | Proof load |
|---|---|---|---|---|
| Class 8.8 | 141 N·m (104 ft-lb) | 105 N·m (78 ft-lb) | 50.2 kN | 67.0 kN |
| Class 10.9 | 201 N·m (148 ft-lb) | 151 N·m (111 ft-lb) | 71.9 kN | 95.8 kN |
| Class 12.9 | 235 N·m (173 ft-lb) | 176 N·m (130 ft-lb) | 84.0 kN | 112.0 kN |

Clamp load = 75 % of proof load. Method: T = K × F × d.

## M14 bolt data

- Thread: M14 × 2 coarse
- Tensile stress area: 115.4 mm²
- Wrench: 21 mm (ISO 4014/4017), 22 mm (DIN 931/933)
- Socket head cap screw hex key: 12 mm
- Tap drill: 12 mm
- Clearance hole (ISO 273): 15 close, 15.5 normal, 16.5 loose (mm)

## Method

Proof stress from ISO 898-1 (580 MPa for 8.8 at this size, 830 MPa for 10.9, 970 MPa for 12.9) × tensile stress area As = π/4 × (d − 0.9382 p)². Target clamp load F = 75 % of proof load. T = K × F × d with K = 0.20 dry, 0.15 lubricated.

## FAQ

**What is the torque for an M14 8.8 bolt?**
About 141 N·m (104 ft-lb) with dry threads and about 105 N·m lubricated, based on 75 % of proof load.

**What is the torque for an M14 10.9 bolt?**
About 201 N·m (148 ft-lb) dry and 151 N·m lubricated.

**What is the torque for an M14 12.9 bolt?**
About 235 N·m (173 ft-lb) dry and 176 N·m lubricated.

**What size wrench fits an M14 bolt?**
21 mm for ISO hex bolts and 22 mm for older DIN hex bolts. An M14 socket head cap screw takes a 12 mm hex key.

**What drill size do I need to tap M14?**
Use a 12 mm drill for M14 × 2 coarse thread.

Source page: https://machinistcharts.com/bolt-torque/m14/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)