#8" Grade 2 Torque Specification

Torque Values by Surface Condition

Stress area: 0.014 in² · Proof load: 770 lbs · Clamp load (75%): 578 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	1.6	2.2	19.2	22.4
Oiled	0.15	1.2	1.6	14.4	16.3
Zinc Plated	0.18	1.4	1.9	16.8	19.4
Waxed	0.1	0.8	1.1	9.6	11.2
MoS₂	0.12	0.9	1.2	10.8	12.2
Galvanized	0.25	2.0	2.7	24.0	27.5

Stress area: 0.01474 in² · Proof load: 811 lbs · Clamp load (75%): 608 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	1.7	2.3	20.4	23.5
Oiled	0.15	1.2	1.6	14.4	16.3
Zinc Plated	0.18	1.5	2.0	18.0	20.4
Waxed	0.1	0.8	1.1	9.6	11.2
MoS₂	0.12	1.0	1.4	12.0	14.3
Galvanized	0.25	2.1	2.8	25.2	28.6

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 55,000 psi × 0.014 in² = 578 lbs

Step 2 — Torque (dry): T = 0.20 × 0.164 in × 578 lbs ÷ 12 = 1.6 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.

Size#8"

Grade2

Diameter0.164" (4.17 mm)

TPI (UNC)32

Tensile74,000 psi

Yield57,000 psi

Proof55,000 psi