#8" Grade 5 Torque Specification

Torque Values by Surface Condition

Stress area: 0.014 in² · Proof load: 1,190 lbs · Clamp load (75%): 892 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	2.4	3.3	28.8	33.7
Oiled	0.15	1.8	2.4	21.6	24.5
Zinc Plated	0.18	2.2	3.0	26.4	30.6
Waxed	0.1	1.2	1.6	14.4	16.3
MoS₂	0.12	1.5	2.0	18.0	20.4
Galvanized	0.25	3.0	4.1	36.0	41.8

Stress area: 0.01474 in² · Proof load: 1,253 lbs · Clamp load (75%): 940 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	2.6	3.5	31.2	35.7
Oiled	0.15	1.9	2.6	22.8	26.5
Zinc Plated	0.18	2.3	3.1	27.6	31.6
Waxed	0.1	1.3	1.8	15.6	18.4
MoS₂	0.12	1.5	2.0	18.0	20.4
Galvanized	0.25	3.2	4.3	38.4	43.8

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 85,000 psi × 0.014 in² = 892 lbs

Step 2 — Torque (dry): T = 0.20 × 0.164 in × 892 lbs ÷ 12 = 2.4 ft·lbs

Proof stress per SAE J429 Table 3. Stress area per ASME B1.1. K-factor per VDI 2230.

Automotive, agricultural equipment, general machinery — the most common high-strength SAE grade. Equivalent to ISO 8.8.

• Torque values are for standard hex bolts with unified threads per ASME B1.1. 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.
• Re-used bolts may have altered friction characteristics. Inspect threads before reuse.

Size#8"

Grade5

Diameter0.164" (4.17 mm)

TPI (UNC)32

Tensile120,000 psi

Yield92,000 psi

Proof85,000 psi