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Fastener Head Markings Decoded
Question: Sometimes there are lines on the bolt head. What do they mean?
Answer: The lines on the head of a bolt indicate its grade. SAE J429 (Society of Automotive Engineers) bolts have radial lines, whereas ASTM (American Society for Testing and Materials) uses a combination of letters and numbers to indicate the grade. Three radial lines will indicate an SAE grade 5 fastener, while six radial lines will indicate an SAE grade 8 fastener. These are the most common grades, but there are others. Our Fastener Identification Markings Chart has a complete list of bolt grades with accompanying head markings.
@Jess Elliott – That sounds like a manufacturer’s head stamp. For example, our grade 5 bolts look like the image above.
The US Patent and Trademark Office has a long list of registered manufacturer head insignia. You might take a look at it and see if any of them match the markings on your bolt.
August 9, 2010 at 9:15 amWe recently received HHCS with “SJ” in addition to the normal three, grade 5 hash marks.
What does the “SJ” mean? Is it manufacturer or a foreign source material standard?
Regards,
July 28, 2010 at 11:16 amJess