A 1/2-inch Grade 5 bolt takes 75.4 ft·lbs (102.2 N·m) dry, or 56.5 ft·lbs oiled. Every size in the range is listed below — click a value for the full spec including all six surface conditions and fine-thread figures.
| Size | TPI (UNC) | ft·lbs (dry) | N·m (dry) | ft·lbs (oiled) |
|---|---|---|---|---|
| #6 | 32 | 1.3 | 1.8 | 1.0 |
| #8 | 32 | 2.4 | 3.3 | 1.8 |
| #10 | 24 | 3.5 | 4.7 | 2.7 |
| 1/4" | 20 | 8.4 | 11.4 | 6.3 |
| 5/16" | 18 | 17.4 | 23.6 | 13.0 |
| 3/8" | 16 | 30.9 | 41.9 | 23.2 |
| 7/16" | 14 | 49.4 | 67.0 | 37.1 |
| 1/2" | 13 | 75.4 | 102.2 | 56.5 |
| 9/16" | 12 | 108.8 | 147.5 | 81.6 |
| 5/8" | 11 | 150.1 | 203.5 | 112.6 |
| 3/4" | 10 | 266.2 | 360.9 | 199.6 |
| 7/8" | 9 | 429.5 | 582.3 | 322.1 |
| 1" | 8 | 643.9 | 873.0 | 482.9 |
| 1-1/8" | 7 | 794.0 | 1076.5 | 595.5 |
| 1-1/4" | 7 | 1120.4 | 1519.1 | 840.3 |
| 1-3/8" | 6 | 1469.0 | 1991.7 | 1101.8 |
| 1-1/2" | 6 | 1949.5 | 2643.2 | 1462.1 |
Dry/plain steel, K = 0.20 · UNC coarse thread · Clamp load 75% of proof load · Click any ft·lbs value for full details
Identification: Three radial lines on the head. Head markings are the only reliable way to tell grades apart — plating and finish tell you nothing about strength.
Material and strength: Medium carbon steel, quenched and tempered. Tensile strength 120,000 psi (105,000 psi above 1"), proof load 85,000 psi (74,000 psi above 1") per SAE J429.
Where it is used: The default automotive and machinery fastener — suspension brackets, engine accessories, general chassis hardware.
Worth knowing: Grade 5 is the most widely used imperial grade. Above 1 inch the specified strength steps down slightly, which is reflected in the torque figures.
Every figure comes from T = K × D × F, where K is the nut factor (0.20 dry, 0.15 oiled), D is nominal diameter, and F is clamp load set at 75% of the bolt's proof load. Proof stress and tensile stress area come from SAE J429.
These are engineering reference values for a standard hex bolt in a steel joint. Where a manufacturer publishes a specific figure for an assembly, that figure takes precedence. Full methodology →
It depends on diameter. A 1/4-inch Grade 5 takes 8.4 ft·lbs, a 1/2-inch takes 75.4 ft·lbs, and a 3/4-inch takes 266.2 ft·lbs — all dry, plain steel, UNC coarse thread. The full table on this page covers #6 through 1-1/2 inch.
Three radial lines on the head. Head markings are the only reliable way to identify grade — never assume from appearance or plating.
Medium carbon steel, quenched and tempered, with a tensile strength of 120,000 psi (105,000 psi above 1") and a proof load of 85,000 psi (74,000 psi above 1") per SAE J429.
Yes. Lubrication cuts the friction coefficient from about 0.20 to 0.15, so the same clamp load needs roughly 25% less torque. A 1/2-inch Grade 5 goes from 75.4 ft·lbs dry to 56.5 ft·lbs oiled.