1-3/8" Grade 5 Torque Specification

Torque Values by Surface Condition

Stress area: 1.155 in² · Proof load: 85,470 lbs · Clamp load (75%): 64,102 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	1469.0	1991.7	17628.0	20309.8
Oiled	0.15	1101.8	1493.8	13221.6	15232.6
Zinc Plated	0.18	1322.1	1792.5	15865.2	18278.5
Waxed	0.1	734.5	995.8	8814.0	10154.4
MoS₂	0.12	881.4	1195.0	10576.8	12185.7
Galvanized	0.25	1836.3	2489.7	22035.6	25388.0

Stress area: 1.315 in² · Proof load: 97,310 lbs · Clamp load (75%): 72,982 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	1672.5	2267.6	20070.0	23123.2
Oiled	0.15	1254.4	1700.7	15052.8	17342.4
Zinc Plated	0.18	1505.3	2040.9	18063.6	20811.5
Waxed	0.1	836.3	1133.9	10035.6	11562.6
MoS₂	0.12	1003.5	1360.6	12042.0	13874.3
Galvanized	0.25	2090.6	2834.5	25087.2	28904.0

Formula: T = K × D × F

Step 1 — Clamp load: F = 0.75 × 74,000 psi × 1.155 in² = 64,102 lbs

Step 2 — Torque (dry): T = 0.20 × 1.375 in × 64,102 lbs ÷ 12 = 1469.0 ft·lbs

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

Same as Grade 5 but with 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.

Size1-3/8"

Grade5

Diameter1.375" (34.92 mm)

TPI (UNC)6

Tensile105,000 psi

Yield81,000 psi

Proof74,000 psi