Rust proofing steel threads?

craker Posts: 1,739
edited December 2009 in Workshop
Trying to repair my car roof cycle carrier.. I ordered some galvanised bolts off ebay but the thread looks a bit short. I've got taps and dies at home so I can extend the thread but that'll take of the galvanised coating.

Is there a DIY fix?


  • Depending on your location - nip down to your local fastener supplier and get some stainless nuts and bolts and solve the problem for ever, it won't be more than a couple of quid.
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  • Paint them. There is also cold galvanizing spray paint in aerosol, but would be cheaper to get new bolts. ... 069515.pdf
  • GavH
    GavH Posts: 933
    Not sure if it'll work, but I was once told to use vaseline on the threads of cleats for golfing shoes as it stopped them rusting and thus siezing.
  • A word of caution when extending bolt threads.

    The original threads are rolled into the metal. This makes the bolt strong by work hardening the metal, it also means that the grain of the metal follows the profile of the thread. When you cut a thread you cut through the grain of the metal and this can cause the bolt to fail prematurely.

    Replacng the bolts is a better option for this reason.
  • lae
    lae Posts: 555
    Grease or vaseline. But new bolts is the easiest and best option.
  • rake
    rake Posts: 3,204
    string never goes rusty.