1/4" Grade 5 Torque Specification

Torque Values by Surface Condition

Stress area: 0.0318 in² · Proof load: 2,703 lbs · Clamp load (75%): 2,027 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	8.4	11.4	100.8	116.2
Oiled	0.15	6.3	8.5	75.6	86.7
Zinc Plated	0.18	7.6	10.3	91.2	105.0
Waxed	0.1	4.2	5.7	50.4	58.1
MoS₂	0.12	5.1	6.9	61.2	70.4
Galvanized	0.25	10.6	14.4	127.2	146.8

Stress area: 0.03637 in² · Proof load: 3,091 lbs · Clamp load (75%): 2,319 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	9.7	13.2	116.4	134.6
Oiled	0.15	7.2	9.8	86.4	99.9
Zinc Plated	0.18	8.7	11.8	104.4	120.3
Waxed	0.1	4.8	6.5	57.6	66.3
MoS₂	0.12	5.8	7.9	69.6	80.6
Galvanized	0.25	12.1	16.4	145.2	167.2

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 85,000 psi × 0.0318 in² = 2,027 lbs

Step 2 — Torque (dry): T = 0.20 × 0.25 in × 2,027 lbs ÷ 12 = 8.4 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.

Size1/4"

Grade5

Diameter0.25" (6.35 mm)

TPI (UNC)20

Tensile120,000 psi

Yield92,000 psi

Proof85,000 psi