SAE J429 (Revised JAN1999), Table 1
Six radial lines. Medium carbon alloy steel, quenched and tempered.
| Size range | Proof | Yield min | Tensile min | Core hardness |
|---|---|---|---|---|
| 1/4 in through 1-1/2 in | 120 ksi (827 MPa) | 130 ksi (896 MPa) | 150 ksi (1034 MPa) | Rockwell C33 to C39 |
Inch grades are published in ksi and metric classes in MPa. The other column on every row is a conversion at 1 ksi = 6.894757 MPa, rounded to the nearest whole unit - it is arithmetic on the published figure, not a second published figure.
Six radial lines on the head, spaced 60 degrees apart, plus the manufacturer's identifier.
Six lines. With Grade 5's three, this is the whole of the count-plus-two rule, and the rule does not extend past these two grades.
Count the radial lines and add two. That rule identifies exactly two grades - SAE Grade 5 with three lines and SAE Grade 8 with six - and it fails everywhere else. Grades 1, 2 and 4 carry no marking at all, so an unmarked head is not evidence of Grade 2; it is evidence of nothing, and unmarked hardware that meets no standard looks exactly the same. ASTM grades are stamped with the specification (A325, A490, BC, BD, 307A) rather than lines, and metric classes are stamped with the class number. Four marking systems share one bin.
Medium carbon alloy steel, quenched and tempered. Highly loaded joints, suspension and driveline work, structural machinery.
One band across the whole range, unlike Grade 5. J429 defines nothing above 1-1/2 in, so a larger bolt is outside the standard rather than merely unlisted.
Over 1/4 in through 1-1/2 in, SAE Grade 8 requires a minimum tensile strength of 150 ksi (1034 MPa), a minimum yield of 130 ksi (896 MPa) and a proof load of 120 ksi (827 MPa).
Six radial lines on the head, spaced 60 degrees apart, plus the manufacturer's identifier.
Medium carbon alloy steel, quenched and tempered. Highly loaded joints, suspension and driveline work, structural machinery.
Twenty-two grades and classes: the SAE J429 inch grades, five ASTM specifications and the ISO 898-1 property classes. It is not every grade in circulation. Stainless classes (ISO 3506 A2 and A4, ASTM F593), the ASTM A193 and A320 high and low temperature grades, ASTM F1554 anchor rod grades and SAE grades 3, 5.1 and 8.1 are not carried here.
Dimensions are as defined by SAE J429 (Revised JAN1999), Table 1. This site is an independent reference and is not affiliated with, endorsed by or approved by any standards body.
Every value on this page was cross-checked against 8 independent published sources:
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