M7 Grade 4.8 Torque Specification

Torque Values by Surface Condition

Stress area: 28.86 mm² · Proof load: 8,947 N · Clamp load (75%): 6,710 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	9.4	6.9	83.2	95.9
Oiled	0.15	7.0	5.2	62.0	71.4
Zinc Plated	0.18	8.5	6.3	75.2	86.7
Waxed	0.1	4.7	3.5	41.6	47.9
MoS₂	0.12	5.6	4.1	49.6	57.1
Galvanized	0.25	11.7	8.6	103.6	119.3

Stress area: 31.23 mm² · Proof load: 9,681 N · Clamp load (75%): 7,261 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	10.2	7.5	90.3	104.0
Oiled	0.15	7.6	5.6	67.3	77.5
Zinc Plated	0.18	9.1	6.7	80.5	92.8
Waxed	0.1	5.1	3.8	45.1	52.0
MoS₂	0.12	6.1	4.5	54.0	62.2
Galvanized	0.25	12.7	9.4	112.4	129.5

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 310 MPa × 28.86 mm² = 6,710 N

Step 2 — Torque (dry): T = 0.20 × 0.0070 m × 6,710 N = 9.4 N·m

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

Light structural connections, furniture assembly, non-load-bearing joints

• 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

Class4.8

Diameter7 mm

Pitch (coarse)1.0 mm

Tensile420 MPa

Yield340 MPa

Proof310 MPa