M12 Grade 4.8 Torque Specification

Torque Values by Surface Condition

Stress area: 84.27 mm² · Proof load: 26,124 N · Clamp load (75%): 19,593 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	47.0	34.7	416.0	479.3
Oiled	0.15	35.3	26.0	312.4	360.0
Zinc Plated	0.18	42.3	31.2	374.4	431.3
Waxed	0.1	23.5	17.3	208.0	239.6
MoS₂	0.12	28.2	20.8	249.6	287.6
Galvanized	0.25	58.8	43.4	520.4	599.6

Stress area: 92.07 mm² · Proof load: 28,542 N · Clamp load (75%): 21,406 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	51.4	37.9	454.9	524.1
Oiled	0.15	38.5	28.4	340.8	392.6
Zinc Plated	0.18	46.2	34.1	408.9	471.1
Waxed	0.1	25.7	19.0	227.5	262.1
MoS₂	0.12	30.8	22.7	272.6	314.1
Galvanized	0.25	64.2	47.4	568.2	654.7

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 310 MPa × 84.27 mm² = 19,593 N

Step 2 — Torque (dry): T = 0.20 × 0.0120 m × 19,593 N = 47.0 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.

SizeM12

Class4.8

Diameter12 mm

Pitch (coarse)1.75 mm

Tensile420 MPa

Yield340 MPa

Proof310 MPa