M6 Grade 4.8 Torque Specification

Torque Values by Surface Condition

Stress area: 20.12 mm² · Proof load: 6,237 N · Clamp load (75%): 4,678 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	5.6	4.1	49.6	57.1
Oiled	0.15	4.2	3.1	37.2	42.8
Zinc Plated	0.18	5.1	3.8	45.1	52.0
Waxed	0.1	2.8	2.1	24.8	28.6
MoS₂	0.12	3.4	2.5	30.1	34.7
Galvanized	0.25	7.0	5.2	62.0	71.4

Stress area: 22.03 mm² · Proof load: 6,829 N · Clamp load (75%): 5,122 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	6.1	4.5	54.0	62.2
Oiled	0.15	4.6	3.4	40.7	46.9
Zinc Plated	0.18	5.5	4.1	48.7	56.1
Waxed	0.1	3.1	2.3	27.4	31.6
MoS₂	0.12	3.7	2.7	32.7	37.7
Galvanized	0.25	7.7	5.7	68.2	78.5

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 310 MPa × 20.12 mm² = 4,678 N

Step 2 — Torque (dry): T = 0.20 × 0.0060 m × 4,678 N = 5.6 N·m

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

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.

SizeM6

Class4.8

Diameter6 mm

Pitch (coarse)1.0 mm

Tensile420 MPa

Yield340 MPa

Proof310 MPa