7/8" Grade 2 Torque Specification

Torque Values by Surface Condition

Stress area: 0.462 in² · Proof load: 15,246 lbs · Clamp load (75%): 11,434 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	166.8	226.2	2001.6	2306.6
Oiled	0.15	125.1	169.6	1501.2	1729.4
Zinc Plated	0.18	150.1	203.5	1801.2	2075.1
Waxed	0.1	83.4	113.1	1000.8	1153.3
MoS₂	0.12	100.1	135.7	1201.2	1383.8
Galvanized	0.25	208.4	282.6	2500.8	2881.7

Stress area: 0.509 in² · Proof load: 16,797 lbs · Clamp load (75%): 12,598 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	183.7	249.1	2204.4	2540.1
Oiled	0.15	137.8	186.8	1653.6	1904.8
Zinc Plated	0.18	165.3	224.1	1983.6	2285.2
Waxed	0.1	91.9	124.6	1102.8	1270.6
MoS₂	0.12	110.2	149.4	1322.4	1523.5
Galvanized	0.25	229.6	311.3	2755.2	3174.4

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 33,000 psi × 0.462 in² = 11,434 lbs

Step 2 — Torque (dry): T = 0.20 × 0.875 in × 11,434 lbs ÷ 12 = 166.8 ft·lbs

Proof stress per SAE J429 Table 3. Stress area per ASME B1.1. K-factor per VDI 2230.

Large general-purpose bolts, same grade but reduced strength at larger diameters

• 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.

Size7/8"

Grade2

Diameter0.875" (22.22 mm)

TPI (UNC)9

Tensile60,000 psi

Yield36,000 psi

Proof33,000 psi