Sep 2025
SAE J995
SAE J995 defines the mechanical and chemical properties of inch-series nuts used across automotive and industrial applications. The standard covers sizes up to 1-1/2" inches and classifies them into three grades – 2, 5, and 8. These grades specify different strength levels and material requirements to suit varied applications. Standard hex pattern nuts in Grades 2, 5, and 8 are commonly stocked and widely used in fastening systems.
SAE J995 Mechanical Properties of Hex Nuts:
| Grade |
Nominal Size (inches) |
Proof Load (psi) |
Rockwell Hardness |
| 2 |
1/4 thru 1-1/2 |
90,000 |
C32 Max |
| 5 |
1/4 thru 1 |
120,000 |
C32 Max |
| Over 1 thru 1-1/2 |
105,000 | C32 Max |
| 8 |
1/4 thru 5/8 | 150,000 | C24-C32 |
| Over 5/8 thru 1 | 150,000 | C26-C34 |
| Over 1 thru 1-1/2 | 150,000 | C26-C36 |
|
SAE J995 Chemical Composition of Hex Nuts :
| Grade |
Carbon (%) |
Phosphorus (%) |
Manganese (%) |
Sulfur (%) |
| 2 |
0.47 max |
0.120 max |
— |
0.15 max |
| 5 |
0.55 max |
0.050 max |
0.30 min |
0.15 max |
| 8 |
0.55 max |
0.040 max |
0.30 min |
0.05 max |
Tensile Stress Areas for UNC and 8 TPI Thread Sizes:
| UNC Thread Size |
Stress Area (sq. in.) |
8 TPI Thread Size |
Stress Area (sq. in.) |
| 1/2-13 |
0.142 |
— |
— |
| 5/8-11 |
0.226 |
— |
— |
| 3/4-10 |
0.334 |
— |
— |
| 7/8-9 |
0.462 |
— |
— |
| 1-8 |
0.606 |
1-8 |
0.606 |
| 1-1/8-7 |
0.763 |
1-1/8-8 |
0.790 |
| 1-1/4-7 |
0.969 |
1-1/4-8 |
1.000 |
| 1-3/8-6 |
1.155 |
1-3/8-8 |
1.233 |
| 1-1/2-6 |
1.405 |
1-1/2-8 |
1.492 |
|