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thread size/pitch rear shocker

Discussion in 'The Garage' started by tyke61, Mar 26, 2020.

  1. tyke61

    tyke61 XS650 New Member XS650.com Supporter

    hi guys,
    whilst rebuilding/light restoring my bike.It came with a box of various nuts that need to go back on it.By mistake i put the wrong pich?thread nut on the top rear shock and have partily stripped the thread.What size thread file do i need to restore it please?
  2. kevski

    kevski XS650 Addict

    kent uk
    Ideally you need a die, you need to measure the bolt diameter it will be a 10 or 12 mm fine pitch.
  3. tyke61

    tyke61 XS650 New Member XS650.com Supporter

    thanks,as iv,e damaged it i thought a die may take off to much metal so a thread file would have been a better idea?
  4. kevski

    kevski XS650 Addict

    kent uk
    The die will be accurate and follow the original line, if it's too badly damaged you may have to have it properly repaired.
    tyke61 likes this.
  5. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

  6. arcticXS

    arcticXS XS650 Guru Top Contributor

    Gary, are you sure about M12x1.50?
    I have never come across that thread. Regular european coarse pitch thread (metric equivalent to UNC) would be M10x1.50 and M12x1.75.
    Japanese bikes and cars generally use M10x1.25 and M12x1.25
    Which is sort af an intermediate thread, as DIN standard fine pitch is actually finer.
    The shock nuts, as well as footpeg mount nuts and exhaust flange nuts are all M10x1.25 on the XS.
    gggGary and tyke61 like this.
  7. gggGary

    gggGary Stop that! XS650.com Supporter Top Contributor

    nah guilty of using a random metric thread chart and believing what they showed. I'll remove it.
  8. DogBunny

    DogBunny Motorcychologist Top Contributor

    IMHO a thread file is probably a better choice than a die in this situation. Use the thread file first, and then if you still need a die it will thread on correctly.
    The thread file doesn't care what the bolt diameter is. Metric thread files are sized by pitch only (SAE thread files are sized by threads per inch). An 8-way metric thread file is not very expensive and very useful. If you have one, you don't need to know either the metric bolt diameter or the pitch. Just try the different faces of the file until you hit on the right one.
    Last edited: Mar 26, 2020
    tyke61, arcticXS, GLJ and 1 other person like this.
  9. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    Hi tyke and welcome,
    if that partially rogered stud end thread can't be fixed, others on this site with that problem have cut the threaded end off with a hacksaw,
    tapped the remaining stud end M6 and held the rear shock on with an M6 bolt & large OD plain washer.
  10. 5twins

    5twins XS650 Guru Top Contributor

    But do get a metric thread file, it's a wonderful tool. I've fixed many, many half buggered up threads on these old bikes with one. Axles in particular seem to need a little attention. Their threaded ends always seem to take a beating.
    tyke61, arcticXS and gggGary like this.
  11. arcticXS

    arcticXS XS650 Guru Top Contributor

    I consider using a die to be last resort. A fine triangular file (for the obvious bad spots), a metric thread file, a smallish hammer, and a regular nut of right diameter and pitch is my preferred "tools". First clean up the worst with the triangular file, then the thread file. Oil the threads lightly, and screw on the nut BY HAND, until feeling resistance. Then tap the nut with the hammer, from all directions. This will flatten any high spots without removing material. Then screw the nut a little bit further, and tap again. This works. If you dont believe me, take a random bolt from your "miscellaneous box", and hammer the threads flat in a couple of spots, bad enough to stop the nut. Then oil it, hit it with the hammer as described, ren the nut a bit further, hit it again, and so on. Before you know it, the nut will screw on like new.
    For wheel axles and swing arm pivot bolts, you don't even need a hammer. Just something a bit substantial, like a vise or anvil, or some other heavy and solid steel object. Just hold the axle as a hammer, and tap the nut against your "anvil" of choice, on all 6 flats, then screw it a bit further, until next rough spot, and repeat.

    My mentor at the shipyard where I did my apprenticeship in the 80s taught me this trick. He was already in his 60s, and absolutely refused to fit any nut or bolt that wouldn't thread on all the way just by hand. And he hated Loctite, Nyloc nuts, and stainless fasteners with a passion :)
    RIP Einar.

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