Better way to check for cracks in cranks?

Discussion in 'Cycling Equipment' started by x, Jun 15, 2003.

Thread Status:
Not open for further replies.
  1. x

    x Guest

    Some months ago, the manager of my LBS showed me a broken crank and pointed out the new-looking core
    and the darker edge - explaining that the darker edge was corrosion from air/water getting into a
    crack that had been there for awhile.

    At that point a little voice said to me "Gee, Pete, you could save yourself a lot of grief someday
    by checking your cranks for cracks every so often".

    Then I forgot all about it.

    Today, just pulling away from a stop, standing on the pedals, my crank broke off. It didn't come out
    too badly - but I think it's just as likely my Better Half could have gotten a phone call from a
    stranger...

    Now the little voice has changed and it's saying "CHECK THE $(%*@#^@%@ CRANKS YOU
    &&^!!!!)*#$^ MORON!"

    The cranks being black and me not being all that obsessive, this is looking to be not quite as
    simple as it sounds.

    Aside from taking them to my friendly local MagnaFlux machine operator, is there a better way than
    just eyeballing them?

    I'm thinking white polishing compound: just wipe a glob of the stuff up and down each crank and
    assume it'll fill in a crack with white and make it stand out.
    -----------------------
    PeteCresswell
     
    Tags:


  2. S. Anderson

    S. Anderson Guest

    "(Pete Cresswell)" <[email protected]> wrote in message news:[email protected]...
    > Some months ago, the manager of my LBS showed me a broken crank and
    pointed out
    > the new-looking core and the darker edge - explaining that the darker edge
    was
    > corrosion from air/water getting into a crack that had been there for
    awhile.
    >

    <<snip..>>

    > Aside from taking them to my friendly local MagnaFlux machine operator, is
    there
    > a better way than just eyeballing them?
    >
    > -----------------------
    > PeteCresswell

    Actually, I think you can buy a sort of do-it-yourself magnaflux kit, at least you used to be able
    to. It's not much more than a liquid and a UV light source. When I built engines I used to have it
    done by the machine shop, but they did say it was very easy and I should do it myself..however, all
    that money in an engine..I just didn't trust myself to do it. So you might be able to buy a small
    kit and go crazy on your parts.

    Cheers,

    Scott..
     
  3. Jon Bond

    Jon Bond Guest

    "S. Anderson" <[email protected]> wrote in message
    news:[email protected]...
    >
    > "(Pete Cresswell)" <[email protected]> wrote in message news:[email protected]...
    > > Some months ago, the manager of my LBS showed me a broken crank and
    > pointed out
    > > the new-looking core and the darker edge - explaining that the darker
    edge
    > was
    > > corrosion from air/water getting into a crack that had been there for
    > awhile.
    > >
    >
    > <<snip..>>
    >
    > > Aside from taking them to my friendly local MagnaFlux machine operator,
    is
    > there
    > > a better way than just eyeballing them?
    > >
    > > -----------------------
    > > PeteCresswell
    >
    > Actually, I think you can buy a sort of do-it-yourself magnaflux kit, at least you used to be able
    > to. It's not much more than a liquid and a UV light source. When I built engines I used to have it
    > done by the machine shop, but they did say it was very easy and I should do it
    myself..however,
    > all that money in an engine..I just didn't trust myself to do it. So you might be able to buy a
    > small kit and go crazy on your parts.
    >
    > Cheers,
    >
    > Scott..

    BTW, how much did that cost? I might do that to my frame before I end up shipping it back to gary
    fisher, if its cheaper than shipping will be. If not, well, I'll let them have at it ;)

    Jon Bond
     
  4. S. Anderson

    S. Anderson Guest

    "Jon Bond" <[email protected]> wrote in message
    news:[email protected]...
    >
    >
    > BTW, how much did that cost? I might do that to my frame before I end up shipping it back to gary
    > fisher, if its cheaper than shipping will be. If not, well, I'll let them have at it ;)
    >
    > Jon Bond
    >
    >

    IIRC, it was about $20 to check a crank, $15-$20 I think. Probably the same for your frame. However,
    the paint may have to be removed where you suspect there is a crack. The liquid may collect in small
    scratches and may LOOK like a crack. Normally, on engine parts, there is no paint in place. I'm not
    sure what the equipment would cost to do it yourself, probably not much more than that.

    Cheers,

    Scott..
     
  5. Marcus Coles

    Marcus Coles Guest

    Jon Bond wrote:
    > "S. Anderson" <[email protected]> wrote in message
    > news:[email protected]...
    >
    >>"(Pete Cresswell)" <[email protected]> wrote in message news:[email protected]...
    >>
    >>>Some months ago, the manager of my LBS showed me a broken crank and
    >>
    >>pointed out
    >>
    >>>the new-looking core and the darker edge - explaining that the darker
    >
    > edge
    >
    >>was
    >>
    >>>corrosion from air/water getting into a crack that had been there for
    >>
    >>awhile.
    >>
    >><<snip..>>
    >>
    >>>Aside from taking them to my friendly local MagnaFlux machine operator,
    >
    > is
    >
    >>there
    >>
    >>>a better way than just eyeballing them?
    >>>
    >>>-----------------------
    >>>PeteCresswell
    >>
    >>Actually, I think you can buy a sort of do-it-yourself magnaflux kit, at least you used to be able
    >>to. It's not much more than a liquid and a UV light source. When I built engines I used to have it
    >>done by the machine shop, but they did say it was very easy and I should do it
    >
    > myself..however,
    >
    >>all that money in an engine..I just didn't trust myself to do it. So you might be able to buy a
    >>small kit and go crazy on your parts.
    >>
    >>Cheers,
    >>
    >>Scott..
    >
    >
    > BTW, how much did that cost? I might do that to my frame before I end up shipping it back to gary
    > fisher, if its cheaper than shipping will be. If not, well, I'll let them have at it ;)
    >
    > Jon Bond
    >
    >
    Check here: http://www.magnaflux.com/index.asp
     
  6. Phil Brown

    Phil Brown Guest

    >Actually, I think you can buy a sort of do-it-yourself magnaflux kit, at least you used to be able
    >to. It's not much more than a liquid and a UV light source.

    That isn't Magnaflux (which only works on ferrous metals) it's Zyglo. Phil Brown
     
  7. S. Anderson

    S. Anderson Guest

    "Phil Brown" <[email protected]> wrote in message
    news:[email protected]...
    >
    > That isn't Magnaflux (which only works on ferrous metals) it's Zyglo. Phil Brown

    That could very well be. I only ever had cast/forged iron stuff Magnafluxed. Have you ever tried
    this at home Phil? I can't see it being that difficult or expensive.

    Cheers,

    Scott..
     
Loading...
Thread Status:
Not open for further replies.
Loading...