M14 Grade 5.8 Torque Specification

Torque Values by Surface Condition

Stress area: 115.44 mm² · Proof load: 43,867 N · Clamp load (75%): 32,900 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	92.1	67.9	815.2	939.2
Oiled	0.15	69.1	51.0	611.6	704.6
Zinc Plated	0.18	82.9	61.1	733.7	845.3
Waxed	0.1	46.1	34.0	408.0	470.1
MoS₂	0.12	55.3	40.8	489.4	563.9
Galvanized	0.25	115.2	85.0	1019.6	1174.7

Stress area: 124.55 mm² · Proof load: 47,329 N · Clamp load (75%): 35,497 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	99.4	73.3	879.8	1013.6
Oiled	0.15	74.5	54.9	659.4	759.7
Zinc Plated	0.18	89.5	66.0	792.1	912.6
Waxed	0.1	49.7	36.7	439.9	506.8
MoS₂	0.12	59.6	44.0	527.5	607.8
Galvanized	0.25	124.2	91.6	1099.3	1266.5

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 380 MPa × 115.44 mm² = 32,900 N

Step 2 — Torque (dry): T = 0.20 × 0.0140 m × 32,900 N = 92.1 N·m

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

General industrial fastening, equipment mounting, moderate structural loads

• 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

Class5.8

Diameter14 mm

Pitch (coarse)2.0 mm

Tensile520 MPa

Yield420 MPa

Proof380 MPa