5/8" Grade 5 Torque Specification

Torque Values by Surface Condition

Stress area: 0.226 in² · Proof load: 19,210 lbs · Clamp load (75%): 14,408 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	150.1	203.5	1801.2	2075.1
Oiled	0.15	112.6	152.7	1351.2	1557.1
Zinc Plated	0.18	135.1	183.2	1621.2	1868.1
Waxed	0.1	75.0	101.7	900.0	1037.1
MoS₂	0.12	90.0	122.0	1080.0	1244.1
Galvanized	0.25	187.6	254.4	2251.2	2594.2

Stress area: 0.256 in² · Proof load: 21,760 lbs · Clamp load (75%): 16,320 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	170.0	230.5	2040.0	2350.5
Oiled	0.15	127.5	172.9	1530.0	1763.1
Zinc Plated	0.18	153.0	207.4	1836.0	2114.9
Waxed	0.1	85.0	115.2	1020.0	1174.7
MoS₂	0.12	102.0	138.3	1224.0	1410.3
Galvanized	0.25	212.5	288.1	2550.0	2937.8

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 85,000 psi × 0.226 in² = 14,408 lbs

Step 2 — Torque (dry): T = 0.20 × 0.625 in × 14,408 lbs ÷ 12 = 150.1 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.

Size5/8"

Grade5

Diameter0.625" (15.88 mm)

TPI (UNC)11

Tensile120,000 psi

Yield92,000 psi

Proof85,000 psi