robertst
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| posted on 21/6/07 at 12:16 PM |
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harness bolts
i have searched around and the common size for the harness bolts seem to be 7/16 UNF.
Question is, can i use 8mm ones instead? or any other metric size for that matter?
Thanks
Tom
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nitram38
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| posted on 21/6/07 at 12:18 PM |
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Whatever you use must be fine thread and have a graded mark of 8.8 for sva
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Peteff
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| posted on 21/6/07 at 12:22 PM |
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Supposed to be equivalent to the 7/16 UNF
which gives you a minimum of an 11mm bolt.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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robertst
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| posted on 21/6/07 at 12:24 PM |
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11mm? i think there's no such thing as an 11mm bolt. i might get 10mm or 12mm which seems a bit overkill for a seat belt.
maybe the top harness mounts would take 12mm?
and the bottom 10 or 8?
what do you think?
Cheers
Tom
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BenB
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| posted on 21/6/07 at 12:29 PM |
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On the quick release Samco harnesses they use 8mm bolts- and after seeing Mr Kubica destruction testing his harness I'd say they work okay....
I've seen a few mentions of the "7/16 or equivalent" floating around recently- is it based upon the manual or heresay? (or some SVA
tester talking out of his sphincter)...
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nitram38
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| posted on 21/6/07 at 12:32 PM |
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All my sva inspector checked was the 8.8 grade as I had mistakenly used two unmarked toyota ones.
I had to change them. He never removed a bolt to check.
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iank
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| posted on 21/6/07 at 12:38 PM |
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The minimum size is 11mm it's in the SVA manual 5.2.4 Note 1.
As Nitram says they must be 8.8 grade or better. (grade S for imperial IIRC)
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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robertst
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| posted on 21/6/07 at 12:41 PM |
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ok just checked the SVA manual... it says a minimum of 11mm.... or comparable strength... so does this mean if i get a 12.9 grade m8 bolt its strength
should be comparable to that of an 8.8 m12?
i'm in the process of welding the plates to the chassis and i want to get it right...
what's the common size on harnesses? 7/16?
Tom
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iank
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| posted on 21/6/07 at 12:49 PM |
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I doubt that reasoning would work, but who knows.
Personally I'd stick with 7/16 grade S, or M12 grade 8.8 given the amount of work it would be to change later on.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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BenB
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| posted on 21/6/07 at 12:56 PM |
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http://www.tech.plym.ac.uk/sme/desnotes/boltb.htm
suggest as 8.8 11mm is stronger than a 8mm 12.9 bolt
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robertst
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| posted on 21/6/07 at 01:08 PM |
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quote:
Originally posted by BenB
http://www.tech.plym.ac.uk/sme/desnotes/boltb.htm
suggest as 8.8 11mm is stronger than a 8mm 12.9 bolt
yep, much stronger...
done, 12mm it is
thanks guys!
Tom
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matt_claydon
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| posted on 21/6/07 at 01:50 PM |
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Since an 8mm bolt has less than half the cross-sectional area of a 12mm bolt, going from 800N/mm2 to 1200N/mm2 tensile strength won't make up
for the loss in area.
For proper European type-approval the specification is that bolts must be 11.11mm dia (i.e. 7/16" ) but alternatives are allowed if they meet
the strength tests. For SVA the requirement is similar, but without the need to test.
[Edited on 21/6/07 by matt_claydon]
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Alex B
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| posted on 23/6/07 at 08:00 AM |
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Mine are 12mm metric and are the Rawl eyebolts from heavy duty construction fixings. They aint marked though........maybe a fail point?
Alex
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