M12 Grade 5.8 Torque Specification

Torque Values by Surface Condition

Stress area: 84.27 mm² · Proof load: 32,023 N · Clamp load (75%): 24,017 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	57.6	42.5	509.8	587.4
Oiled	0.15	43.2	31.9	382.4	440.5
Zinc Plated	0.18	51.9	38.3	459.4	529.2
Waxed	0.1	28.8	21.2	254.9	293.7
MoS₂	0.12	34.6	25.5	306.2	352.8
Galvanized	0.25	72.1	53.2	638.1	735.2

Stress area: 92.07 mm² · Proof load: 34,987 N · Clamp load (75%): 26,240 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	63.0	46.5	557.6	642.4
Oiled	0.15	47.2	34.8	417.8	481.3
Zinc Plated	0.18	56.7	41.8	501.8	578.2
Waxed	0.1	31.5	23.2	278.8	321.2
MoS₂	0.12	37.8	27.9	334.6	385.5
Galvanized	0.25	78.7	58.0	696.6	802.5

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 380 MPa × 84.27 mm² = 24,017 N

Step 2 — Torque (dry): T = 0.20 × 0.0120 m × 24,017 N = 57.6 N·m

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

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.

SizeM12

Class5.8

Diameter12 mm

Pitch (coarse)1.75 mm

Tensile520 MPa

Yield420 MPa

Proof380 MPa