M6 Grade 12.9 Torque Specification

Torque Values by Surface Condition

Stress area: 20.12 mm² · Proof load: 19,516 N · Clamp load (75%): 14,637 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	17.6	13.0	155.8	179.5
Oiled	0.15	13.2	9.7	116.8	134.6
Zinc Plated	0.18	15.8	11.7	139.8	161.1
Waxed	0.1	8.8	6.5	77.9	89.7
MoS₂	0.12	10.5	7.7	92.9	107.1
Galvanized	0.25	22.0	16.2	194.7	224.3

Stress area: 22.03 mm² · Proof load: 21,369 N · Clamp load (75%): 16,027 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	19.2	14.2	169.9	195.8
Oiled	0.15	14.4	10.6	127.5	146.8
Zinc Plated	0.18	17.3	12.8	153.1	176.4
Waxed	0.1	9.6	7.1	85.0	97.9
MoS₂	0.12	11.5	8.5	101.8	117.3
Galvanized	0.25	24.0	17.7	212.4	244.7

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 970 MPa × 20.12 mm² = 14,637 N

Step 2 — Torque (dry): T = 0.20 × 0.0060 m × 14,637 N = 17.6 N·m

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

Socket head cap screws, racing/motorsport, aerospace, maximum strength applications — highest standard grade

• 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.

SizeM6

Class12.9

Diameter6 mm

Pitch (coarse)1.0 mm

Tensile1220 MPa

Yield1100 MPa

Proof970 MPa