M7 Grade 5.8 Torque Specification

Torque Values by Surface Condition

Stress area: 28.86 mm² · Proof load: 10,967 N · Clamp load (75%): 8,225 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	11.5	8.5	101.8	117.3
Oiled	0.15	8.6	6.3	76.1	87.7
Zinc Plated	0.18	10.4	7.7	92.0	106.1
Waxed	0.1	5.8	4.3	51.3	59.1
MoS₂	0.12	6.9	5.1	61.1	70.4
Galvanized	0.25	14.4	10.6	127.5	146.8

Stress area: 31.23 mm² · Proof load: 11,867 N · Clamp load (75%): 8,901 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	12.5	9.2	110.6	127.5
Oiled	0.15	9.3	6.9	82.3	94.8
Zinc Plated	0.18	11.2	8.3	99.1	114.2
Waxed	0.1	6.2	4.6	54.9	63.2
MoS₂	0.12	7.5	5.5	66.4	76.5
Galvanized	0.25	15.6	11.5	138.1	159.1

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 380 MPa × 28.86 mm² = 8,225 N

Step 2 — Torque (dry): T = 0.20 × 0.0070 m × 8,225 N = 11.5 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.

SizeM7

Class5.8

Diameter7 mm

Pitch (coarse)1.0 mm

Tensile520 MPa

Yield420 MPa

Proof380 MPa