M10 Grade 6.8 Torque Specification

Torque Values by Surface Condition

Stress area: 58.0 mm² · Proof load: 25,520 N · Clamp load (75%): 19,140 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	38.3	28.2	339.0	390.6
Oiled	0.15	28.7	21.2	254.0	292.7
Zinc Plated	0.18	34.5	25.4	305.4	351.8
Waxed	0.1	19.1	14.1	169.0	194.8
MoS₂	0.12	23.0	17.0	203.6	234.5
Galvanized	0.25	47.9	35.3	424.0	488.4

Stress area: 61.2 mm² · Proof load: 26,928 N · Clamp load (75%): 20,196 N

Surface Condition	K Factor	N·m	ft·lbs	in·lbs	kgf·cm
Plain/Dry	0.2	40.4	29.8	357.6	412.0
Oiled	0.15	30.3	22.3	268.2	309.0
Zinc Plated	0.18	36.4	26.8	322.2	371.2
Waxed	0.1	20.2	14.9	178.8	206.0
MoS₂	0.12	24.2	17.8	214.2	246.8
Galvanized	0.25	50.5	37.2	447.0	515.0

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 440 MPa × 58.0 mm² = 19,140 N

Step 2 — Torque (dry): T = 0.20 × 0.0100 m × 19,140 N = 38.3 N·m

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

Industrial machinery, agricultural equipment, elevated load requirements

• 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.

SizeM10

Class6.8

Diameter10 mm

Pitch (coarse)1.5 mm

Tensile600 MPa

Yield480 MPa

Proof440 MPa