3/8" Grade 5 Torque Specification

Torque Values by Surface Condition

Stress area: 0.0775 in² · Proof load: 6,588 lbs · Clamp load (75%): 4,941 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	30.9	41.9	370.8	427.3
Oiled	0.15	23.2	31.5	278.4	321.2
Zinc Plated	0.18	27.8	37.7	333.6	384.4
Waxed	0.1	15.4	20.9	184.8	213.1
MoS₂	0.12	18.5	25.1	222.0	255.9
Galvanized	0.25	38.6	52.3	463.2	533.3

Stress area: 0.0878 in² · Proof load: 7,463 lbs · Clamp load (75%): 5,597 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	35.0	47.5	420.0	484.4
Oiled	0.15	26.2	35.5	314.4	362.0
Zinc Plated	0.18	31.5	42.7	378.0	435.4
Waxed	0.1	17.5	23.7	210.0	241.7
MoS₂	0.12	21.0	28.5	252.0	290.6
Galvanized	0.25	43.7	59.2	524.4	603.7

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 85,000 psi × 0.0775 in² = 4,941 lbs

Step 2 — Torque (dry): T = 0.20 × 0.375 in × 4,941 lbs ÷ 12 = 30.9 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.

Size3/8"

Grade5

Diameter0.375" (9.52 mm)

TPI (UNC)16

Tensile120,000 psi

Yield92,000 psi

Proof85,000 psi