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"High strength bolt testing and marking Q&A"

Current question and answers:

April 16, 2021

Q. I have some M6 x 1 x 35mm flange bolts and would like to know what testing is required for this size bolt per the ISO 898-1 [affil. link to spec at Techstreet].

Alex Hernandez
student - Chicago, Illinois

April 2021

A. Hi Alex. Sorry but there are many thousands of specs and standards and I have no need for that spec, so I don't have it. You've indicated that you are a student and those specs can be prohibitively expensive for student papers, so if any reader can help you, I hope they do!

But if you are interning, that's a whole different matter. If your company has accepted or is bidding upon a contract calling for ISO-898-1 fasteners, they absolutely must obtain that spec for themselves, not rely on anyone's interpretation or summary of it.

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Previous closely related Q&A's, oldest first:

August 21, 2016

Q. I want to know what is the purpose of marking the manufacturer trade symbol and the grade of the bolt 8.8 and above on the head of the bolt? And could it be a reason for rejection of the bolts? What about if the contractor received the bolts and fixed them and after a while he claimed that he does not want them because there was no marking on the heads as per BS 3692 [affil. link to spec at Techstreet].

Mohamed Mohamed

August 2016

Hi Mohamed. The marking is for essentially the same reason as for labeling anything else in the world: so people know what it is -- grade 8.8 high strength bolt -- and who has certified that it is what it is marked (the manufacturer's symbol). The markings are deliberately raised rather than depressed because that makes forgery substantially harder (unlike stamped letering, raised letters can essentially only be done at the time of manufacture).

Certainly it is not necessary to label all hardware -- every hardware store in the world has shelves full of unlabeled bolts -- but it could be a life-threatening disaster if those hardware store bolts were used where high strength grade 8.8 bolts are needed. If the contract called for grade 8.8 bolts, I think you're not going to find supporting material that labeling is not a necessary part of the 8.8 standard. Good luck.


pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

August 22, 2016

Q. Thank you Ted for this valuable answer. Does the BS 3692 [affil. link to spec at Techstreet] and ISO 898-1 [affil. link to spec at Techstreet] -1988 specify that such standards cannot be applied to used bolts and nuts, i.e., mechanical and chemical properties requirements?

Mohamed Mohamed [returning]
- Dubai, UAE

A. Sorry, Mohamed, but while I'd like to continue trying to help, you absolutely must not lob the requirements for standards compliance into someone else's court :-)

You are offering products that are required to comply with standards, and you absolutely must obtain those standards yourself and assure for yourself that you are in full compliance; you cannot rely on someone's else's summary of the requirements. Good luck.


pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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