M7 Grade 9.8 Torque Specification

Torque Values by Surface Condition

Stress area: 28.86 mm² · Proof load: 18,759 N · Clamp load (75%): 14,069 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	19.7	14.5	174.4	200.9
Oiled	0.15	14.8	10.9	131.0	150.9
Zinc Plated	0.18	17.7	13.1	156.7	180.5
Waxed	0.1	9.8	7.2	86.7	99.9
MoS₂	0.12	11.8	8.7	104.4	120.3
Galvanized	0.25	24.6	18.1	217.7	250.9

Stress area: 31.23 mm² · Proof load: 20,300 N · Clamp load (75%): 15,225 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	21.3	15.7	188.5	217.2
Oiled	0.15	16.0	11.8	141.6	163.2
Zinc Plated	0.18	19.2	14.2	169.9	195.8
Waxed	0.1	10.7	7.9	94.7	109.1
MoS₂	0.12	12.8	9.4	113.3	130.5
Galvanized	0.25	26.6	19.6	235.4	271.2

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 650 MPa × 28.86 mm² = 14,069 N

Step 2 — Torque (dry): T = 0.20 × 0.0070 m × 14,069 N = 19.7 N·m

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

Heavy-duty automotive, high-performance machinery (limited availability, mostly M16 and smaller)

• 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

Class9.8

Diameter7 mm

Pitch (coarse)1.0 mm

Tensile900 MPa

Yield720 MPa

Proof650 MPa