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  1. #1
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    Is this stem safe to use?

    Hi all, I just wanted to get some opinions on this "new" stem I've bought. It was advertised as NOS, but has some mysterious markings on the underside, like so;





    I contacted the seller, who said that it was perhaps just the finish on the stem. The the innerside of the clamp and the inserting column are clean as a whistle, no marks or scratches at all so odds are it is NOS after all. Has anyone ever seen markings like this on a stem, and am I going to die if I use it? Of course I won't hold anyone responsible, I'm just after opinions...

  2. #2
    Senior Member gmorris's Avatar
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    Looks like a casting mark. Depending on the depth, I would say it's completely superficial

  3. #3
    It's an old photo Boss Moniker's Avatar
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    +1 for casting marks, but you never can be too sure. Stems failing isn't too uncommon. What I would do is sand the underside down to make sure they don't go too deep. Maybe use a file or dremel (lightly). Then you'd want to polish it up.. here's a nice thread about how to do that: Do It Yourself (DIY)
    Quote Originally Posted by dutret View Post
    Just because I'm not angry anymore doesn't mean I don't think bossmoniker and every other hipster **** I see riding around on aerowheels isn't a piece of **** thats only use is to be an easy target for ridicule.

  4. #4
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    thanks for the quick response - will give the ole file and polish a go!

  5. #5
    Senior Member Joshua A.C. New's Avatar
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    Yeah, that looks to me like the mold wasn't up to temperature when that was cast, but I'd be pretty surprised if it was more than a millimeter deep.
    Joshua A.C. Newman,
    Passionate lover of construction

  6. #6
    Sometimes knows stuff. rmfnla's Avatar
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    Quote Originally Posted by Boss Moniker View Post
    +1 for casting marks, but you never can be too sure. Stems failing isn't too uncommon. What I would do is sand the underside down to make sure they don't go too deep. Maybe use a file or dremel (lightly). Then you'd want to polish it up.. here's a nice thread about how to do that: Do It Yourself (DIY)
    Yeah, but the good news is they don't usually fail in that particular area.
    Today, I believe my jurisdiction ends here...

  7. #7
    Perineal Pressurized dobber's Avatar
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    Agree with the sand and polish.
    This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.

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    I would think that emery tape that plumbers use would take those marks out and shine at the same time. If the marks did not come out I would be wary.

  9. #9
    Senior Member Grand Bois's Avatar
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    It looks to me like the stem is anodized, so sanding will ruin the finish unless you strip off all of the anodizing and polish the whole thing.

    They look like scratches to me.

  10. #10
    or tarckeemoon, depending marqueemoon's Avatar
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    Quote Originally Posted by Dirtdrop View Post
    It looks to me like the stem is anodized, so sanding will ruin the finish unless you strip off all of the anodizing and polish the whole thing.

    They look like scratches to me.
    +1

    It's on the underside of the stem. I personally would grease it up, put it on my bike, and ride it. I am not anal retentive enough to care about such things.

  11. #11
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    from experience with cars... anything NOS is just the assembly line rejects, id have to agree with poor casting on this but double check it just the same.

  12. #12
    Hammer Time C_LOGAN's Avatar
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    Quote Originally Posted by Dirtdrop View Post
    It looks to me like the stem is anodized, so sanding will ruin the finish unless you strip off all of the anodizing and polish the whole thing.

    They look like scratches to me.
    I agree. You will need to sand and polish the whole stem - and lose the finish - as if you sand + polish one area there will be a haze between the anodised metal and the sanded/polished. I suppose it will not matter if it is on a part of the stem which is not visible.

    I would send it back to the seller, as it is not perfect at all - and I suppose in the back of your mind you may always be paranoid of it snapping...

  13. #13
    Non Tribuo Anus Rodentum and off to the next adventure (RIP) Stacey's Avatar
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    Magnaflux it to be sure!

  14. #14
    Sometimes knows stuff. rmfnla's Avatar
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    Quote Originally Posted by Stacey View Post
    Magnaflux it to be sure!
    Yeah, 'cause everone has that stuff lying around.
    Today, I believe my jurisdiction ends here...

  15. #15
    Senior Member Bill Kapaun's Avatar
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    Quote Originally Posted by Stacey View Post
    Magnaflux it to be sure!
    So did you invent some new method to Magnaflux non ferrous metals?

  16. #16
    just ride
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    I am pretty conservative regarding safety, so if it were my stem I would deep six it. Aluminum alloy is susceptible to fatigue breaking and some people recommend regularly replacing stems even when they show no signs of distress. Since your stem already shows irregularities, these are likely to become stress risers from which cracks may propigate at some point. Since no one knows what that point may be, why chance it ? I would be especially concerned if you regularly get out of the saddle to climb since you will be putting torsion in this area.

    I'm not an expert and I've never seen a stem fail, so I'm not speaking form first hand experience - just what I've read. But my impression from what I've read is "don't mess around with stems"

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