SAE J995 covers the mechanical and chemical requirements for inch series nuts in three grades used in automotive and related industries in sizes to 1-1/2” inclusive. SAE J995 Grades 2, 5, and 8 nuts are readily available in a standard hex pattern.
J995 Mechanical Properties
| Grade |
Nominal Size, inches |
Proofload, UNC and UN 8 Threads, 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 |
| *Values listed are not normally applicable to jam, slotted, castle, heavy or thick nuts. |
J995 Chemical Requirements
| 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 |
J995 Tensile Stress Area
| Thread, UNC |
UNC Stress Area, sq inches |
Thread, 8TPI |
8 TPI Stress Area, sq inches |
| 1/2-13 |
0.1419 |
|
|
| 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 |
| To calculate individual nut proofload value, simply multiply the tensile stress area by the appropriate psi proofload value. |
