Speedmart Tech Support
Head Marking |
Grade/Class, |
|
Mechanical Properties | ||
Proof Load |
Min. Yield Strength |
Min. Tensile Strength | |||
US Bolts | |||||
|
Grade 2 Low or medium carbon steel, not for use on race cars. |
1/4 thru 3/4 |
55,000 |
57,000 |
74,000 |
Over 3/4 thru 1-1/2 |
33,000 |
36,000 |
60,000 | ||
|
Grade 5 Medium Carbon Steel, Quenched and Tempered, do to the stress and vibrations involved in racing these are not recommended for use on race cars. |
1/4 thru 1 |
85,000 |
92,000 |
120,000 |
Over 1 thru 1-1/2 |
74,000 |
81,000 |
105,000 | ||
|
Grade 8 Medium Carbon Alloy Steel, Quenched and Tempered, highly recommended for use in racing. |
1/4 thru 1-1/2 |
120,000 |
130,000 |
150,000 |
Hex Bolts
Hex bolts are measured from under the head to the tip of the bolt.
For fasteners that are designed to be countersunk, the measurement is made from the point on the head where the surface of the material is, to the end of the fastener
Countersunk