1-1/4" Grade 2 Torque Specification

Torque Values by Surface Condition

Stress area: 0.969 in² · Proof load: 31,977 lbs · Clamp load (75%): 23,983 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	499.6	677.4	5995.2	6907.6
Oiled	0.15	374.7	508.0	4496.4	5180.2
Zinc Plated	0.18	449.7	609.7	5396.4	6217.2
Waxed	0.1	249.8	338.7	2997.6	3453.8
MoS₂	0.12	299.8	406.5	3597.6	4145.2
Galvanized	0.25	624.6	846.8	7495.2	8635.0

Stress area: 1.073 in² · Proof load: 35,409 lbs · Clamp load (75%): 26,557 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	553.3	750.2	6639.6	7649.9
Oiled	0.15	414.9	562.5	4978.8	5735.9
Zinc Plated	0.18	497.9	675.1	5974.8	6884.1
Waxed	0.1	276.6	375.0	3319.2	3824.0
MoS₂	0.12	332.0	450.1	3984.0	4589.8
Galvanized	0.25	691.6	937.7	8299.2	9561.9

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 33,000 psi × 0.969 in² = 23,983 lbs

Step 2 — Torque (dry): T = 0.20 × 1.25 in × 23,983 lbs ÷ 12 = 499.6 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.

Size1-1/4"

Grade2

Diameter1.25" (31.75 mm)

TPI (UNC)7

Tensile60,000 psi

Yield36,000 psi

Proof33,000 psi