#10 Grade 5 Bolt Torque: 3.5 ft·lbs / 4.7 N·m

Torque Values by Surface Condition

UNC — Coarse Thread — 24 TPI

Stress area: 0.0175 in² · Proof load: 1,488 lbs · Clamp load (75%): 1,116 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	3.53	4.79	42.4	48.8
Oiled	0.15	2.65	3.59	31.8	36.6
Zinc Plated	0.18	3.18	4.31	38.2	44.0
Waxed	0.1	1.77	2.39	21.2	24.4
MoS₂	0.12	2.12	2.87	25.4	29.3
Galvanized	0.25	4.42	5.99	53.0	61.1

UNF — Fine Thread — 32 TPI

Stress area: 0.02 in² · Proof load: 1,700 lbs · Clamp load (75%): 1,275 lbs

Surface Condition	K Factor	ft·lbs	N·m	in·lbs	kgf·cm
Plain/Dry	0.2	4.04	5.47	48.5	55.8
Oiled	0.15	3.03	4.11	36.3	41.9
Zinc Plated	0.18	3.63	4.93	43.6	50.2
Waxed	0.1	2.02	2.74	24.2	27.9
MoS₂	0.12	2.42	3.28	29.1	33.5
Galvanized	0.25	5.05	6.84	60.6	69.8

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 1.77 ft·lbs (waxed) to 4.42 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 × 0.0175 in² = 1,116 lbs

Step 2 — Torque (dry): T = 0.20 × 0.19 in × 1,116 lbs ÷ 12 = 3.5 ft·lbs

Proof stress per SAE J429 Table 3. Stress area per ASME B1.1. Typical K-factor, consistent with VDI 2230 friction values. SAE J429 formally covers 1/4" to 1-1/2" diameters; for numbered machine screws these figures apply the same grade proof stress (as used for Grade 5/8 machine screws sold to SAE-equivalent strength) — check the screw supplier's rating.

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

Size#10

Grade5

Diameter0.19" (4.83 mm)

TPI (UNC)24

Tensile120,000 psi

Yield92,000 psi

Proof85,000 psi

#10 Grade 5 Torque Spec