I need a screw! (M7 Content)

  • This topic has 23 replies, 12 voices, and was last updated 5 years ago by  Drac.
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  • I need a screw! (M7 Content)
  • Roofrack woes πŸ™ Now I need to source an M7 Bolt/Screw.

    Google and previous training seems to be telling me I need M7 Socket-Button/Socket-Cap/Allen-Head-Cap ones. Ideally stainless-steel. Sadly Google is not telling me where to buy them πŸ™

    B&Q and Screwfix have also let me down (they don’t do any M7 stuff apparently).

    Ebay have regular steel ones for $999.99 (yes that is the genuine price and ‘people’ are watching the auction)

    Help! Can anyone point me in the right direction?

    Google a local “fixings” supplier.

    andyl
    Member

    http://www.inoxbolt.co.uk/zen/index.php?main_page=product_info&cPath=189_328_531&products_id=974&zenid=b72a2ae7abbd4a7baf0ee3784ac0d82f

    What make roof rack. You have to make sure you get the correct tensile grade. I remember Thule had a recall to replace some failing bolts a while back.

    Blimey DD, that was quick!!!

    Many thanks, I now have a couple of possible leads, but any more ideas gratefully received πŸ™‚

    Premier Icon maccruiskeen
    Subscriber

    M7 does seem to be a bit rare, looking a the places I buy from – Buck & Hickman or Orbital Fasterners – they sell taps for making m7 threads in holes but nothing you can actually screw into that threaded hole once you’ve done that

    Beware as Jamie talks some rare sense there. M7 is unusual. All my Thule bolts have been M6 – and if I’m not mistaken, most mounting holes in car rooves are M6 as standard aren’t they?

    @Jamie – Yup, def M7. I was suprised as well, but managed to find a couple of M7 bolts that I thought would do the job. The thread is fine, but the head had to be ‘modified’ to make it fit and is a bit ‘string and sellotape’ so I need a better fix

    @andyl – Worrying info as I know far to little about Tensile strength πŸ™

    PS – It’s the car that dictates the thread. I tried M6 and M8, but when I called the roofrack manufacturers they were adamant that it was M7 and when I managed to buy the hex-head bolts they were a perfect fit :-/

    No, no, I insist…it must be M6. πŸ˜€

    @DD – Can I put your ‘name’ on the insurance document as a guaranteed source of info re the M6 bit? πŸ˜‰

    @Jamie – I have just ordered some from SJS, many thanks πŸ˜€ NB there must be some Karma in the fact that it is a bike site/shop

    @Everyone else who replied – Many thanks for the info/knowledge πŸ˜€

    Jamie
    Member

    Glad to hear you got sorted. 20mm seems a bit short though, and I hope they are the correct tensile strength.

    As an aside, do the roof bar manufacturers not offer spares?

    They are actually about 12-15mm long so I need to cut them down hence the preferance for stainless rather than coated/plated

    As for the roofbar peeps, it was roofbox.co.uk who seem great/helpfull :-), but they are just a dealer so spares are an issue

    Tensile strength is still making me ‘twitch’ though. Can you point me in the direction of any knowledge?

    irc
    Member

    Tensile strength is still making me ‘twitch’ though. Can you point me in the direction of any knowledge?

    Posting from a position of engineering ignorance would the fact most roof bolts are M6 while yours is M7 and therefore beefier not be enough insurance?

    Its not M7 – its 1/4″ x 28 otherwise known as 1/4″UNF. Tensile strength should be 12.9, don’t use stainless – go with nickel plated steel.

    Mikeypies
    Member

    I am not sure about using stainless for load bearing bolts where a failure could Cause the rack to fail. Here is some info I found

    http://www.volksbolts.com/faq/basics.htm

    I would be looking for high tensile bolts tbh if they are under any stress

    I would be looking for high tensile bolts tbh if they are under any stress

    Tensile strength should be 12.9, don’t use stainless

    Premier Icon Drac
    Subscriber

    Contact Thule with your woes about they’re great product they have a good history of customer service so may well send you some.

    cheez0
    Member

    Drill it out.. tap it M8. Job done

    footflaps
    Member

    Contact Thule with your woes about they’re great product they have a good history of customer service so may well send you some.

    Not a very safe product though, the Thule bolts I had regularly snapped letting the bike carrier depart from the roof of the car and each time Thule just said ‘yes, it happens a lot’ and posted out a new bolt which then snapped a few months later….

    Hmmm more ideas/comments since last night. In summary

    Its def M7. I borrowed some calipers and dug out my old engineers ref book and it is not 1/4″UNF

    It’s a lease vehicle so drilling and tapping is not an option

    It looks as if most of the ‘load’ is taken elsewhere, I ‘think’ these bolts are just there to stop the roofrack sliding round a bit so shear stregth is the most important bit

    It’s not a Thule rack so they would not/could not help (although I do have 2 thule racks in the garage from previous cars so could try a blag, but the comment about thier bolts breaking above puts me off a bit…)

    Looks like I need High Tensile bolts from a local company that I can ask questions (for such a small sale value as well, I already feel sorry for them)

    Premier Icon Drac
    Subscriber

    Ah not sure where I picked it up it was a Thule one from.

    I’ve had Thule bars and carriers for about 17 years now and never had a bolt snap. πŸ˜€

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