M14 Grade 10.9 Torque Specification

Torque Values by Surface Condition

Stress area: 115.44 mm² · Proof load: 95,815 N · Clamp load (75%): 71,861 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	201.2	148.4	1780.8	2051.7
Oiled	0.15	150.9	111.3	1335.6	1538.8
Zinc Plated	0.18	181.1	133.6	1602.9	1846.7
Waxed	0.1	100.6	74.2	890.4	1025.8
MoS₂	0.12	120.7	89.0	1068.3	1230.8
Galvanized	0.25	251.5	185.5	2226.0	2564.6

Stress area: 124.55 mm² · Proof load: 103,376 N · Clamp load (75%): 77,532 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	217.1	160.1	1921.5	2213.8
Oiled	0.15	162.8	120.1	1440.9	1660.1
Zinc Plated	0.18	195.4	144.1	1729.4	1992.5
Waxed	0.1	108.5	80.0	960.3	1106.4
MoS₂	0.12	130.3	96.1	1153.3	1328.7
Galvanized	0.25	271.4	200.2	2402.1	2767.5

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 830 MPa × 115.44 mm² = 71,861 N

Step 2 — Torque (dry): T = 0.20 × 0.0140 m × 71,861 N = 201.2 N·m

Proof stress per ISO 898-1:2013 Table 4. Stress area per ISO 898-1 Annex A. K-factor per VDI 2230.

Structural steel (equivalent to ASTM A490), heavy machinery, high-strength critical joints, pressure vessels

• Torque values are for standard hex bolts with ISO metric threads. Socket head cap screws may have different requirements.
• Lubrication reduces required torque significantly — using dry torque values on lubricated bolts risks exceeding yield strength.
• For critical or safety-related applications, always consult the manufacturer's specifications or applicable design standard (e.g., VDI 2230).
• Re-used bolts may have altered friction characteristics. Inspect threads before reuse.

SizeM14

Class10.9

Diameter14 mm

Pitch (coarse)2.0 mm

Tensile1040 MPa

Yield940 MPa

Proof830 MPa