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Old 27th May 2013, 11:35   #21
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That simplifies it a lot, thanks.
Wiki doesn't help much other than illustrating why I asked: http://en.wikipedia.org/wiki/Screw

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Old 27th May 2013, 12:41   #22
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They are flanged head bolts. Given the softness of the head I would be surprised if the bolt is that hard, but it could have been induction hardened. They are 60mm including the head (I know I should have measured the threaded portion), and as you can see, a good 5mm is non-loaded.
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Old 27th May 2013, 12:42   #23
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Sorry, should have uploaded the photo!

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Old 27th May 2013, 13:03   #24
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The end of that screw has been specially machined, I wonder why ? Looks part bleed nipple part self tapper - weird, especially at M12. What function is that conical end performing I wonder.
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Old 27th May 2013, 13:16   #25
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Quote:
Originally Posted by Froggy-Mk2 View Post
The end of that screw has been specially machined, I wonder why ? Looks part bleed nipple part self tapper - weird, especially at M12. What function is that conical end performing I wonder.
Looks like it's designed to also locate the part as well as hold it and the end of the bolt is designed to locate properly, to minimise any cross-threading!
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Old 27th May 2013, 13:39   #26
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Quote:
Originally Posted by MrDoodles View Post
Looks like it's designed to also locate the part as well as hold it and the end of the bolt is designed to locate properly, to minimise any cross-threading!
That makes sense, but then it would mean this is a special screw, not an off-the-shelf
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Old 27th May 2013, 13:45   #27
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Quote:
Originally Posted by Froggy-Mk2 View Post
That makes sense, but then it would mean this is a special screw, not an off-the-shelf
Correct!

I'm on the phone at the moment, have you looked on the Rimmers site for availability?
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Old 27th May 2013, 14:30   #28
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Rimmers NLA, Brown and Gammon NLA, X-Part 1 off - and thats all the google results pull up with that part number
I have also found a posting from another forum that shows them NLA in May 2006, and they confirm its M12 fine thread too.
Its starting to look like a special run off from a machine shop
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Old 27th May 2013, 15:15   #29
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If you can find a machine shop that will happily work with 12.9 grade bolts! Although there is no stamping on the head of these so it is possible (unlikely) that these are "normal" steel. I think the end of the thread is designed to clean out the threads as they are removed, like a tap. I doubt if it gives any physical properties to the bolt. Interestingly Rover only recommend a torque load of 100Nm which is not a lot, given the stresses on these bolts. Just going from 8.8 to 12.9 bolts gives a 30% increase in strength, but I just wonder how much stress these bolts need to take?
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Old 27th May 2013, 15:39   #30
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Hi, I would use these with a suitable washer https://www.spaldingfasteners.co.uk/...olts-grade-129

Regards John
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