M7 Grade 12.9 Torque Specification

Torque Values by Surface Condition

Stress area: 28.86 mm² · Proof load: 27,994 N · Clamp load (75%): 20,996 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	29.4	21.7	260.2	299.8
Oiled	0.15	22.0	16.2	194.7	224.3
Zinc Plated	0.18	26.5	19.5	234.5	270.2
Waxed	0.1	14.7	10.8	130.1	149.9
MoS₂	0.12	17.6	13.0	155.8	179.5
Galvanized	0.25	36.7	27.1	324.8	374.2

Stress area: 31.23 mm² · Proof load: 30,293 N · Clamp load (75%): 22,720 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	31.8	23.5	281.5	324.3
Oiled	0.15	23.9	17.6	211.5	243.7
Zinc Plated	0.18	28.6	21.1	253.1	291.6
Waxed	0.1	15.9	11.7	140.7	162.1
MoS₂	0.12	19.1	14.1	169.0	194.8
Galvanized	0.25	39.8	29.4	352.3	405.8

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 970 MPa × 28.86 mm² = 20,996 N

Step 2 — Torque (dry): T = 0.20 × 0.0070 m × 20,996 N = 29.4 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.

SizeM7

Class12.9

Diameter7 mm

Pitch (coarse)1.0 mm

Tensile1220 MPa

Yield1100 MPa

Proof970 MPa