SAE J429 covers the mechanical and material requirements for inch series fasteners
used in automotive and related industries in sizes to 1-1/2” inclusive.
Below is a basic summary the most common grades. SAE J429 covers a number of other grades
and grade variations not covered in this summary, including 4, 5.1, 5.2, 8.1, and 8.2.
| J429 Mechanical Properties |
| Grade |
Nominal Size, inches |
Full Size Proofload, psi |
Yield Strength, min, psi |
Tensile Strength, min, psi |
Elong, min, % |
RA, min, % |
Core Hardness, Rockwell |
Tempering Temperature, min |
| 1 |
1/4 thru 1-1/2 |
33,000 |
36,000 |
60,000 |
18 |
35 |
B7 to B100 |
N/A |
| 2 |
1/4 thru 3/4 |
55,000 |
57,000 |
74,000 |
18 |
35 |
B80 to B100 |
N/A |
| Over 3/4 thru 1-1/2 |
33,000 |
36,000 |
60,000 |
18 |
35 |
B70 to B100 |
| 5 |
1/4 thru 1 |
85,000 |
92,000 |
120,000 |
14 |
35 |
C25 to C34 |
800F |
| Over 1 thru 1-1/2 |
74,000 |
81,000 |
105,000 |
14 |
35 |
C19 to C30 |
| 8 |
1/4 thru 1-1/2 |
120,000 |
130,000 |
150,000 |
12 |
35 |
C33 to C39 |
800F |
| Grade 2 requirements for sizes 1/4" thru 3/4" apply only to bolts 6" and shorter,
and to studs of all lengths. For bolts longer than 6", Grade 1 requirements shall apply. |
| J429 Chemical Requirements |
| Grade |
Material |
Carbon, % |
Phosphorus, % |
Sulfur, % |
Grade Marking |
| 1 |
Low or Medium Carbon Steel |
0.55 max |
0.030 max |
0.050 max |
None |
| 2 |
Low or Medium Carbon Steel |
0.15 - 0.55 |
0.030 max |
0.050 max |
None |
| 5 |
Medium Carbon Steel |
0.28 - 0.55 |
0.030 max |
0.050 max |
 |
| 8 |
Medium Carbon Alloy Steel |
0.28 - 0.55 |
0.030 max |
0.050 max |
 |
| J429 Recommended Hardware |
| Nuts |
Washers |
| J995 |
N/A |
For fasteners larger than 1-1/2″ in diameter, the following ASTM grades should be considered.
| Alternate Grades |
| SAE J429 Grade |
ASTM Equivalent |
| Grade 1 |
A307 Grades A or B |
| Grade 2 |
A307 Grades A or B |
| Grade 5 |
A449 |
| Grade 8 |
A354 Grade BD |
| This chart compares SAE and ASTM specifications that are similar but not identical in diameters through 1½". |