3/8" Grade 2 Torque Specification

Torque Values by Surface Condition

Stress area: 0.0775 in² · Proof load: 4,262 lbs · Clamp load (75%): 3,197 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	20.0	27.1	240.0	276.3
Oiled	0.15	15.0	20.3	180.0	207.0
Zinc Plated	0.18	18.0	24.4	216.0	248.8
Waxed	0.1	10.0	13.6	120.0	138.7
MoS₂	0.12	12.0	16.3	144.0	166.2
Galvanized	0.25	25.0	33.9	300.0	345.7

Stress area: 0.0878 in² · Proof load: 4,829 lbs · Clamp load (75%): 3,622 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	22.6	30.6	271.2	312.0
Oiled	0.15	17.0	23.0	204.0	234.5
Zinc Plated	0.18	20.4	27.7	244.8	282.5
Waxed	0.1	11.3	15.3	135.6	156.0
MoS₂	0.12	13.6	18.4	163.2	187.6
Galvanized	0.25	28.3	38.4	339.6	391.6

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 55,000 psi × 0.0775 in² = 3,197 lbs

Step 2 — Torque (dry): T = 0.20 × 0.375 in × 3,197 lbs ÷ 12 = 20.0 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.

Size3/8"

Grade2

Diameter0.375" (9.52 mm)

TPI (UNC)16

Tensile74,000 psi

Yield57,000 psi

Proof55,000 psi