Hi, looking at bolt markings what are ok for HT use. Some are 8.8 which i think are HT but not sure what other markings mean they are HT. Can anyone help.
Thanks

10.9 is considered to be HT

Would 8.8 not be recommended for suspension/wishbone bolts etc then?

i was under the impression 8.8 and up were high tensile.

all my suspension bolts are 8.8 M12s. even at that, they're massively overspecced for the job.

tom

8.8. 10.9 and 12.9 are the common HT metric. Imperial equivalents have different markings (different numbers of lines usually).

Unless you know what you are doing don't use stainless bolts in the suspension. I've also read in one of my books that 12.9 should be avoided (very strong, but break instead of bend when they do let go).

8.8 is fine for suspension stuff. I used higher grades only for stuff like harnesses (especially when they're the smaller 8mm not the 7/16UNF ones)

8.8 is HT and just fine.

The higher the grade number the higher the UTS and elastic limmit BUT the less warning you get of failure.

Any bolt that isn't marked on the head can be any old rubbish.

It is also important to buy from a reputable source, such as Unbrako, Alen etc

Bear in mind that the 8.8, 10.9 etc is only a number on the head. Anybody can put any number on a bolt head of dubious quality........................

Thanks for the response. With the ones with lines etc what does it all mean?

For imperial I believe 3 radial lines means grade 'S' which is equivalent to 8.8

do a google search for 'bolt head markings' if you have something else, there seem to be a lot of different marks used around the world.

Thats good ive got a few of them but i'l try to keep to the 8.8's. Any good online suppliers for HT bolts?

I've used Namrick who are pretty good.
Do a search and you will find some others.

http://www.namrick.co.uk