9/16" Grade 5 Bolt Torque: 108.8 ft·lbs / 147.5 N·m

Torque Values by Surface Condition

UNC — Coarse Thread — 12 TPI

Stress area: 0.182 in² · Proof load: 15,470 lbs · Clamp load (75%): 11,602 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	108.8	147.5	1305.3	1503.8
Oiled	0.15	81.6	110.6	979.0	1127.9
Zinc Plated	0.18	97.9	132.7	1174.8	1353.5
Waxed	0.1	54.4	73.8	652.6	751.9
MoS₂	0.12	65.3	88.5	783.2	902.3
Galvanized	0.25	136.0	184.4	1631.6	1879.8

UNF — Fine Thread — 18 TPI

Stress area: 0.203 in² · Proof load: 17,255 lbs · Clamp load (75%): 12,941 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	121.3	164.5	1455.9	1677.4
Oiled	0.15	91.0	123.4	1091.9	1258.0
Zinc Plated	0.18	109.2	148.1	1310.3	1509.6
Waxed	0.1	60.7	82.3	727.9	838.7
MoS₂	0.12	72.8	98.7	873.5	1006.4
Galvanized	0.25	151.7	205.7	1819.9	2096.7

Torque by surface condition

UNC thread, ft·lbs. Values from the table above.

Same bolt, same target clamp load: thread friction alone moves the required torque from 54.4 ft·lbs (waxed) to 136.0 ft·lbs (hot-dip galvanized), 2.5× as much. Match the row to the fastener's actual finish and lubrication.

How This Value Is Calculated

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 85,000 psi × 0.182 in² = 11,602 lbs

Step 2 — Torque (dry): T = 0.20 × 0.5625 in × 11,602 lbs ÷ 12 = 108.8 ft·lbs

Proof stress per SAE J429 Table 3. Stress area per ASME B1.1. Typical K-factor, consistent with VDI 2230 friction values.

When to Use Grade 5

Automotive, agricultural equipment, general machinery — the most common high-strength SAE grade. Equivalent to ISO 8.8.

Important Notes

• 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.

Specifications

Size9/16"

Grade5

Diameter0.5625" (14.29 mm)

TPI (UNC)12

Tensile120,000 psi

Yield92,000 psi

Proof85,000 psi

9/16" Grade 5 Torque Spec