1/4" Grade 2 Torque Specification

Torque Values by Surface Condition

Stress area: 0.0318 in² · Proof load: 1,749 lbs · Clamp load (75%): 1,312 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	5.5	7.5	66.0	76.5
Oiled	0.15	4.1	5.6	49.2	57.1
Zinc Plated	0.18	4.9	6.6	58.8	67.3
Waxed	0.1	2.7	3.7	32.4	37.7
MoS₂	0.12	3.3	4.5	39.6	45.9
Galvanized	0.25	6.8	9.2	81.6	93.8

Stress area: 0.03637 in² · Proof load: 2,000 lbs · Clamp load (75%): 1,500 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	6.3	8.5	75.6	86.7
Oiled	0.15	4.7	6.4	56.4	65.3
Zinc Plated	0.18	5.6	7.6	67.2	77.5
Waxed	0.1	3.1	4.2	37.2	42.8
MoS₂	0.12	3.8	5.2	45.6	53.0
Galvanized	0.25	7.8	10.6	93.6	108.1

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 55,000 psi × 0.0318 in² = 1,312 lbs

Step 2 — Torque (dry): T = 0.20 × 0.25 in × 1,312 lbs ÷ 12 = 5.5 ft·lbs

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

General-purpose, non-critical bolting. Most common ungraded hardware-store bolts.

• 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"

Grade2

Diameter0.25" (6.35 mm)

TPI (UNC)20

Tensile74,000 psi

Yield57,000 psi

Proof55,000 psi