M5 Grade 4.8 Torque Specification

Torque Values by Surface Condition

Stress area: 14.18 mm² · Proof load: 4,396 N · Clamp load (75%): 3,297 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	3.3	2.4	29.2	33.7
Oiled	0.15	2.5	1.8	22.1	25.5
Zinc Plated	0.18	3.0	2.2	26.6	30.6
Waxed	0.1	1.6	1.2	14.2	16.3
MoS₂	0.12	2.0	1.5	17.7	20.4
Galvanized	0.25	4.1	3.0	36.3	41.8

Stress area: 16.13 mm² · Proof load: 5,000 N · Clamp load (75%): 3,750 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	3.8	2.8	33.6	38.7
Oiled	0.15	2.8	2.1	24.8	28.6
Zinc Plated	0.18	3.4	2.5	30.1	34.7
Waxed	0.1	1.9	1.4	16.8	19.4
MoS₂	0.12	2.3	1.7	20.4	23.5
Galvanized	0.25	4.7	3.5	41.6	47.9

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 310 MPa × 14.18 mm² = 3,297 N

Step 2 — Torque (dry): T = 0.20 × 0.0050 m × 3,297 N = 3.3 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.

SizeM5

Class4.8

Diameter5 mm

Pitch (coarse)0.8 mm

Tensile420 MPa

Yield340 MPa

Proof310 MPa