M5 Grade 9.8 Torque Specification

Torque Values by Surface Condition

Stress area: 14.18 mm² · Proof load: 9,217 N · Clamp load (75%): 6,913 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	6.9	5.1	61.1	70.4
Oiled	0.15	5.2	3.8	46.0	53.0
Zinc Plated	0.18	6.2	4.6	54.9	63.2
Waxed	0.1	3.5	2.6	31.0	35.7
MoS₂	0.12	4.1	3.0	36.3	41.8
Galvanized	0.25	8.6	6.3	76.1	87.7

Stress area: 16.13 mm² · Proof load: 10,484 N · Clamp load (75%): 7,863 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	7.9	5.8	69.9	80.6
Oiled	0.15	5.9	4.4	52.2	60.2
Zinc Plated	0.18	7.1	5.2	62.8	72.4
Waxed	0.1	3.9	2.9	34.5	39.8
MoS₂	0.12	4.7	3.5	41.6	47.9
Galvanized	0.25	9.8	7.2	86.7	99.9

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 650 MPa × 14.18 mm² = 6,913 N

Step 2 — Torque (dry): T = 0.20 × 0.0050 m × 6,913 N = 6.9 N·m

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

Heavy-duty automotive, high-performance machinery (limited availability, mostly M16 and smaller)

• 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

Class9.8

Diameter5 mm

Pitch (coarse)0.8 mm

Tensile900 MPa

Yield720 MPa

Proof650 MPa