1/2" Grade 2 Torque Specification

Torque Values by Surface Condition

Stress area: 0.1419 in² · Proof load: 7,804 lbs · Clamp load (75%): 5,853 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	48.8	66.2	585.6	675.1
Oiled	0.15	36.6	49.6	439.2	505.8
Zinc Plated	0.18	43.9	59.5	526.8	606.7
Waxed	0.1	24.4	33.1	292.8	337.5
MoS₂	0.12	29.3	39.7	351.6	404.8
Galvanized	0.25	61.0	82.7	732.0	843.3

Stress area: 0.1599 in² · Proof load: 8,794 lbs · Clamp load (75%): 6,596 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	55.0	74.6	660.0	760.7
Oiled	0.15	41.2	55.9	494.4	570.0
Zinc Plated	0.18	49.5	67.1	594.0	684.2
Waxed	0.1	27.5	37.3	330.0	380.4
MoS₂	0.12	33.0	44.7	396.0	455.8
Galvanized	0.25	68.7	93.1	824.4	949.4

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 55,000 psi × 0.1419 in² = 5,853 lbs

Step 2 — Torque (dry): T = 0.20 × 0.5 in × 5,853 lbs ÷ 12 = 48.8 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.

Size1/2"

Grade2

Diameter0.5" (12.70 mm)

TPI (UNC)13

Tensile74,000 psi

Yield57,000 psi

Proof55,000 psi