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  1. #1
    :jarckass: deathhare's Avatar
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    NJS hubs forged?

    Are all NJS hubs forged?

  2. #2
    i don't stop travsi's Avatar
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    ..nope, a few of them are genuine.

  3. #3
    Hi. I'm in Delaware. Robbykills's Avatar
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    no only yours are counterfeit.



    zing.

  4. #4
    i don't stop travsi's Avatar
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    my real answer is: all the ones i've ever seen are forged,
    that is to say not cnc-machined. but i don't know if they are
    cold or hot forged ...i would assume hot.

  5. #5
    :jarckass: deathhare's Avatar
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    I read somewhere once that some arent or werent.
    It seems to me that with the NJS certification that there would have to be some sort of leveled manufacturing for all of them to comply with NJS. Unless maybe the rules changed at some point.
    Basically i wanted to know if theyre all forged but i guess more specifically whether or not my Sansin hubs are forged.
    thanks

  6. #6
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    This has been covered before, but NJS hubs (and equivalent hubs in other drillings) are actually manufactured by a technique called metalspinning. A blank is put in a metalworking lathe and spun rapidly. A relatively dull tool is then pushed against it and causes the metal to flow gradually to form the shape of the hub, much like one would push clay into shape while spinning on a potter's wheel. You typically make a separate blank for each side and then put them together and use spinning to fuse the two halves together. You will occasionally see signs of this fusion joint at the centerline of the hub.

    Metalspinning works out the stresses and any flaws in the metal extremely well so the hubs have very low failure rates from cracking. It also allows the hub flanges to be made very thin (i.e., lightweight) without compromising strength. Spinning doesn't compact the metal structure like forging so it doesn't offer the strength of forging, but forging isn't really relevant for hub design -- spinning is actually a better method. Forging works better for products taking strikes (such as hammer faces) or for products facing lever forces (wrenches, crankarms, etc.). And forging works much better when many forging steps are used (the top Sugino crankarms are forged something like 23 times while 75's are only forged about 6-8 times, for example); on hubs, there isn't much opportunity to do to many forging steps. If one uses a stress-relieved billet of aluminum and then mills (CNCs) it you can get the same net performance as with spinning but you have to leave more metal in place so CNC'd hubs tend to be heavier.

  7. #7
    raodmaster shaman
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    Very interesting. Thanks!

    since we are on the subject, how many of the cranks out there are forged as opposed to cast?

  8. #8
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    Nice one 11.4

  9. #9
    Senior Member nateintokyo's Avatar
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    somewhat related (since Sugino cranks came up):

    I was talking to a representative from Sugino a few weeks back and asked about comparative stiffness between the 75's and Mighty's. He said the 75's were stiffer by design. The Grand Mighty are made to be a bit more pliant. He said experienced riders with very smooth cadence appreciate the slight flex on the Mighty and don't suffer from much power loss since they are efficient, while riders who are sloppier or sprinting more aggressively should benefit from the stiffer 75's.

  10. #10
    :jarckass: deathhare's Avatar
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    Good info Nate.

  11. #11
    oldsprinter oldsprinter's Avatar
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    Quote Originally Posted by 11.4 View Post
    This has been covered before, but NJS hubs (and equivalent hubs in other drillings) are actually manufactured by a technique called metalspinning. A blank is put in a metalworking lathe and spun rapidly. A relatively dull tool is then pushed against it and causes the metal to flow gradually to form the shape of the hub, much like one would push clay into shape while spinning on a potter's wheel. You typically make a separate blank for each side and then put them together and use spinning to fuse the two halves together. You will occasionally see signs of this fusion joint at the centerline of the hub..
    So this means Campagnolo C-Record NJS ("Sherrif Star") hubs are made entirely differently to the normal C-Record hubs?

  12. #12
    :jarckass: deathhare's Avatar
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    My hubs are from the 80s too and im thinking they didnt have this hi-tech process back then. Same with the campys im guessing.
    So...forged?

  13. #13
    ganbatte! sashae's Avatar
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    Quote Originally Posted by deathhare View Post
    My hubs are from the 80s too and im thinking they didnt have this hi-tech process back then. Same with the campys im guessing.
    So...forged?
    Previously, on bikeforums.net!

    Quote Originally Posted by 11.4
    You really have to abuse your hubs to have a problem with Campagnolo hubs. Campy made steel hubs back in the 50's, but they had three-piece bodies and actually weren't all that good. In the 60's they came out with their all-aluminum one-piece Record hubs, which were so good that they were simply adopted into Campy's Super Record line (and not even called Super Record). They were finally replaced by the C-Record ("sheriff's star") hubs. The Record hubs are readily identifiable because they had the elongated oval holes on the flanges rather than the triangular ones on the C-Record. They were made of a softer alloy that resisted cracking better and they were manufactured by a method called spinning. In this method, a thick-walled aluminum tube was put on a metalworking lathe and special tools were pushed against the metal as it spun at high speed. It actually caused the metal to flow (or be pushed -- imagine how clay would move under your hands while you spin it on a potter's wheel). Spinning causes the metal of the flanges to rise up while the central portion of the hub decreases in diameter and becomes very thin. This method has the great benefit of removing stresses and weaknesses from the metal so it's much less prone to breakage (it has many of the same benefits as forging the metal). This is the same method used for Suntour Superbe Pro and Dura Ace 7600 high flange hubs. Campy used this method up until they came out with the C-Record line (the "sheriff's star" track and road hubs), at which point they simply turned the hubs on a lathe. Unlike Phil Wood, which used special high grade aluminum blanks and made their flanges sufficiently strong, Campy used what was frankly pretty cheap aluminum and then machined it more (it wasn't the best of times for Campagnolo). Now the upside is that it was a good bit lighter than a current Phil Wood hub, but the negative was that it wasn't absolutely bombproof.

  14. #14
    :jarckass: deathhare's Avatar
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    Weird. I would have thought that NJS would have required all hubs to be made with the same process.

  15. #15
    do-over... SugarPILL's Avatar
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    It is a very interesting process, there is a pretty big metal spinning shop just down the way from mine.

    I could sit and watch for hours, they can do huge domes and stuff... here is a clip although not the best camera quality.

    http://www.youtube.com/watch?v=o4KhTg66ctg

  16. #16
    oldsprinter oldsprinter's Avatar
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    Quote Originally Posted by sashae View Post
    Previously, on bikeforums.net!

    So, I'm still confused. I'd seen that quote about the Sherrif Star hubs being lathed - which is not the same as forged - and yet, it is possible to buy Sherri Star NJS hubs - which begs the question, are the Sherrif Star NJS hubs manufactured to NJS standards (ie forged) and therefore a far better hub than was sold outside of Japan?

  17. #17
    LF for the accentdeprived
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    Why does everyone think that NJS officials prescribe to you how you work your goddamn metals? I imagine they couldn't care less. Material, design... those may be controlled. Processes... hopefully not.
    Quote Originally Posted by dutret
    Do you deny that you are clueless or do you just think that "moron" didn't need to be tacked on there?
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  18. #18
    ganbatte! sashae's Avatar
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    None of the NJS hubs are forged -- see 11.4's original post about spinning.

  19. #19
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    The Sheriff's Star Campy C-Record hubs are milled (same method as CNC but not computer driven). Campy equipment at that time had huge status in the keirin circuit and riders with rare Nuovo Record track components were envied. Women married them for their Nuovo Record track groups.

    Well, this certainly helped get an NJS stamp for the C-Record track ensemble. Here's a good example of how NJS certification doesn't really mean you have the best equipment -- like with the Shimano Dura Ace 7410 seatpost, C-record components just weren't all that good, at least in their early configurations (think about the aero seatposts breaking, about the problems with Delta brakes, and the early C-Record cranks). But the equipment did get a certification. It's identical to non-stamped equipment (except for the stamp of course). There's no piece-by-piece testing when it leaves the factory, but when you build up a NJS wheel and plan to race it at a parimutuel keirin track, the wheel is then subjected to stringent testing. You have to pay a fee for every piece of equipment that gets stamped, which is why Campy only did a fairly small amount of the stuff. The word got out in Japan eventually that the C-Record stuff was pretty but not as reliable as Sanshin, Suntour, etc., and demand withered. Campy didn't really bother to pursue that market again. They were at the low point in their manufacturing history and it took a few years to get back in stride. Today they hardly care about track and offer just a paltry range of dimensions in some very dated equipment. They haven't spent a dollar on track equipment design in fifteen years. They simply see the road market as their focus.

  20. #20
    cab horn
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    Not to mention the sheriff star hubs had a habit of blowing up.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  21. #21
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    Quote Originally Posted by operator View Post
    Not to mention the sheriff star hubs had a habit of blowing up.
    Yes. I think that was implicit in some of the posts above. The metallurgy wasn't all that great and the hub design was focused more on aesthetics than on mechanical integrity. The result was a hub that had more than its share of failures.

    The C-Record hub also had the useless cosmetic dust covers on the ends of the hubs. They needed a special Campy cap puller that's of course no longer made and very expensive when you find them. Alternatively, you can make do with a couple hacksaw blades, but you risk dinging a hub every time you want to service or adjust the hubs. The only redeeming grace is that the dust covers had a tendency to loosen a bit over time and either fall off on their own (or rattle incessantly while riding). Italian design at its best -- like a 1970s Fiat. Thank heaven that Campy came back from that debacle.

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