How are nipple threads made?

Discussion in 'Cycling Equipment' started by Jt, Jun 20, 2003.

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  1. Jt

    Jt Guest

    Spoke threads are rolled (usually).

    Are nipple threads made with a forming tap?
     
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  2. Skuke

    Skuke Guest

    On Fri, 20 Jun 2003 15:53:27 -0300, jt wrote:

    > Spoke threads are rolled (usually).
    >
    > Are nipple threads made with a forming tap?

    Speaking from a machinist point of view, I'd say yes.

    The form taps (also called roll taps) would probably cause a slight deformation of the outside
    diameter (due to the relatively thin wall), so the milling of the wrench flats would be a later
    operation and eliminate the "bulging". I would think that a form tap would be used for both Aluminum
    and brass nipples. The brass tends to be "grabbier" and has a tendency to grab the small taps and
    break them. But since nipples are probably made by the gazillion on a Swiss screw machine, and those
    usually run in a oil flood, it shouldn't really be a problem especially once the process is
    optimized.

    The form taps are also stronger since there is no flute for chip removal and thus more body for
    strength. However, they are more critical of tap hole diameter. You need an accurate size hole for
    proper threading and thread strength. Accurate holes size is not a problem for Swiss screw machines.

    As with roll forming the spokes threads, I'd would think the forming (as opposed to cutting) of
    female threads in the nipples have a similar increase in strength.

    --
    Skuke Reverse the domain name to send email
     
  3. A Muzi

    A Muzi Guest

    "jt" <[email protected]> wrote in message
    news:[email protected]...
    > Spoke threads are rolled (usually).
    >
    > Are nipple threads made with a forming tap?

    What's a "forming tap"?

    Nipples are headed from brass , milled for the wrench flats*, threaded with our industry's odd
    2x56tpi** tap, milled for the end slot, then tumble-plated.

    I have a Torringon one with half of a tap still in it, and several other aberrant spokes and nipples
    from a lifetime of handling them.

    *or, for six sided format, cut from hex stock. **or the appropriate diameter if else.
    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  4. Jobst Brandt

    Jobst Brandt Guest

    I have not seen how they are made but I have seen spoke nipples that were forged to final shape
    except for the screwdriver slot. Their wrench flats were formed in a die that gave a transition from
    the round body that could not be created by machining. I suspect these also have had formed rather
    than cut threads.

    http://tinyurl.com/ewlz

    In any case, "express" taps produce a stronger thread than cutting taps. Just the same I see many
    machined spoke nipples.

    Jobst Brandt [email protected] Palo Alto CA
     
  5. Jobst Brandt

    Jobst Brandt Guest

    I have not seen how they are made but I have seen spoke nipples that were forged to final shape
    except for the screwdriver slot. Their wrench flats were formed in a die that gave a transition from
    the round body that could not be created by machining. I suspect these also have had formed rather
    than cut threads.

    http://www.besly.com/stdtaps.htm http://tinyurl.com/ewlz

    In any case, "X-press" taps produce a stronger thread than cutting taps. Just the same I see many
    machined spoke nipples.

    Jobst Brandt [email protected] Palo Alto CA
     
  6. Skuke

    Skuke Guest

    On Sat, 21 Jun 2003 08:09:40 -0500, A Muzi wrote:

    > What's a "forming tap"?

    A form or roll tap as they are known (not express, which I believe is a trade name) does not cut
    female threads. They "mash" them into shape. Not that different than rolling the male threads on
    spokes. The forming/rolling/mashing... keeps the grain structure of the material "flowing". If you
    were to cut the threads the grain gets interupted and a loss of strength is the result.

    Take a look at the links that Jobst posted. They show what a form tap looks like. Pretty much looks
    like a regular tap except there is no cutting edge or flute (for chip evacuation).

    FWIW, larger form taps (some 1/4", most 5/16 and up) have a very narrow flute on one side. I don't
    know what it's for since it's too small for chips. It maybe a place to trap some cutting oils.

    >
    > Nipples are headed from brass , milled for the wrench flats*, threaded with our industry's odd
    > 2x56tpi**

    2-56 taps are not odd, unusual, rare or otherwise different. I've been cutting (or forming) that
    thread for 20 years. It may be strange in the bike industry only because most things are metric
    threaded. Except of course for pedals, BB... I guess there have been too many "standards" in the
    bike industry and now there is just a mish-mash bastardization of standards for a bike.

    --
    Skuke Reverse the domain name to send email
     
  7. Skuke

    Skuke Guest

    On Sat, 21 Jun 2003 20:46:41 GMT, [email protected] wrote:

    > I have not seen how they are made but I have seen spoke nipples that were forged to final shape
    > except for the screwdriver slot. Their wrench flats were formed in a die that gave a transition
    > from the round body that could not be created by machining.

    Hmmm? A progressive die would be a good, fast way to make strong nipples. When did you see this?? A
    modern Swiss screw machine with a "live" head(s) could mill the flats, saw the screwdriver slot,
    drill and tap pretty darn quickly. Might be a toss-up for speed, but the die method may be stronger.
    Cold forging if you will. Then again, the die method may require a second setup and machine which
    would then require human handling and increase time and costs.

    --
    Skuke Reverse the domain name to send email
     
  8. Jobst Brandt

    Jobst Brandt Guest

    Skuke who? writes:

    >> I have not seen how they are made but I have seen spoke nipples that were forged to final shape
    >> except for the screwdriver slot. Their wrench flats were formed in a die that gave a transition
    >> from the round body that could not be created by machining.

    > Hmmm? A progressive die would be a good, fast way to make strong nipples. When did you see this??
    > A modern Swiss screw machine with a "live" head(s) could mill the flats, saw the screwdriver slot,
    > drill and tap pretty darn quickly. Might be a toss-up for speed, but the die method may be
    > stronger. Cold forging if you will. Then again, the die method may require a second setup and
    > machine which would then require human handling and increase time and costs.

    All the spoke nipples (DT) I use at the present time are cold formed and I am fairly certain that
    the thread is also formed, not cut although the thread shows brass while the nipple is plated. I
    think the blanks are formed and plated then drilled, form threaded, and slotted by screw machines.

    Jobst Brandt [email protected] Palo Alto CA
     
  9. Skuke

    Skuke Guest

    On Sun, 22 Jun 2003 04:36:46 GMT, [email protected] wrote:

    > Skuke who? writes:

    Lywalker of course! :)

    --
    Skuke Reverse the domain name to send email
     
  10. Jim Adney

    Jim Adney Guest

    >"jt" <[email protected]> wrote in message
    >news:[email protected]...
    >> Spoke threads are rolled (usually).
    >>
    >> Are nipple threads made with a forming tap?

    I have a nipple that came from the factory with a normal fluted cutting tap broken off in it.

    In the same box I also got a few nipples that had no center hole and a few with a center hole, but
    no threads. I assume the latter came thru the threading maching before anyone noticed that the tap
    was broken.

    -
    -----------------------------------------------
    Jim Adney [email protected] Madison, WI 53711 USA
    -----------------------------------------------
     
  11. A Muzi

    A Muzi Guest

    > On Sat, 21 Jun 2003 08:09:40 -0500, A Muzi wrote:
    > > What's a "forming tap"?

    "skuke" <[email protected]> wrote in message news:[email protected]...
    > A form or roll tap as they are known (not express, which I believe is a trade name) does not cut
    > female threads. They "mash" them into shape.
    Not
    > that different than rolling the male threads on spokes. The forming/rolling/mashing... keeps the
    > grain structure of the material "flowing". If you were to cut the threads the grain gets
    > interupted and a loss of strength is the result.
    >
    > Take a look at the links that Jobst posted. They show what a form tap looks like. Pretty much
    > looks like a regular tap except there is no cutting edge or flute (for chip evacuation).
    >
    > FWIW, larger form taps (some 1/4", most 5/16 and up) have a very narrow flute on one side. I don't
    > know what it's for since it's too small for chips. It maybe a place to trap some cutting oils.
    >
    >
    >
    >
    > >
    > > Nipples are headed from brass , milled for the wrench flats*, threaded
    with
    > > our industry's odd 2x56tpi**
    >
    > 2-56 taps are not odd, unusual, rare or otherwise different. I've been cutting (or forming) that
    > thread for 20 years. It may be strange in the bike industry only because most things are metric
    > threaded. Except of course for pedals, BB... I guess there have been too many "standards" in the
    > bike industry and now there is just a mish-mash bastardization of standards for a bike.

    I knew these as "rolling taps".. Hadn't heard "forming" before. Thanks.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  12. Chalo

    Chalo Guest

    skuke <[email protected]> wrote:

    > On Sat, 21 Jun 2003 08:09:40 -0500, A Muzi wrote:
    >
    > > Nipples are headed from brass , milled for the wrench flats*, threaded with our industry's odd
    > > 2x56tpi**
    >
    > 2-56 taps are not odd, unusual, rare or otherwise different. I've been cutting (or forming) that
    > thread for 20 years. It may be strange in the bike industry only because most things are metric
    > threaded.

    Well if you had been a cycle-centric machinist during your tenure, you might have noticed that
    spokes are not threaded #2-56, but rather 2mm-56tpi, which *is* a strange bastard thread; Mr. Muzi
    is right about that. #2-56 thread is close, in that a #2-56 nut will spin on to a 14ga spoke
    thread, but the fit is too loose and a nipple would be prone to thread failure if it were tapped
    with that thread.

    True to form, 15ga spokes are threaded 1.8mm-56tpi.

    It's analogous to some of the threads of the Italian standard which mix a metric diameter with an
    inch pitch, e.g. 10mm-26tpi axles in Campy hubs. Italian BBs are what, 36mm-24tpi? It defies
    understanding unless you assume that Italian industry were getting their thread cutting equipment
    from Old Blighty.

    Chalo Colina
     
  13. Skuke

    Skuke Guest

    On 23 Jun 2003 00:23:02 -0700, Chalo wrote:

    > skuke <[email protected]> wrote:
    >
    >> On Sat, 21 Jun 2003 08:09:40 -0500, A Muzi wrote:
    >>
    >>> Nipples are headed from brass , milled for the wrench flats*, threaded with our industry's odd
    >>> 2x56tpi**
    >>
    >> 2-56 taps are not odd, unusual, rare or otherwise different. I've been cutting (or forming) that
    >> thread for 20 years. It may be strange in the bike industry only because most things are metric
    >> threaded.
    >
    > Well if you had been a cycle-centric machinist during your tenure, you might have noticed that
    > spokes are not threaded #2-56, but rather 2mm-56tpi, which *is* a strange bastard thread; Mr. Muzi
    > is right about that. #2-56 thread is close, in that a #2-56 nut will spin on to a 14ga spoke
    > thread, but the fit is too loose and a nipple would be prone to thread failure if it were tapped
    > with that thread.
    >
    > True to form, 15ga spokes are threaded 1.8mm-56tpi.
    >
    > It's analogous to some of the threads of the Italian standard which mix a metric diameter with an
    > inch pitch, e.g. 10mm-26tpi axles in Campy hubs. Italian BBs are what, 36mm-24tpi? It defies
    > understanding unless you assume that Italian industry were getting their thread cutting equipment
    > from Old Blighty.
    >
    > Chalo Colina

    Thanks! I learned something new today.

    Yes, I misread/understood Mr. Muzi's statement to be #2-56tpi and not 2mm-56tpi.

    How on Earth did the bike industry wind up with that bastardization of a thread "standard"??

    BTW, I do consider myself to be a cycling-centric machinist. I've made many custom component for
    myself and others. I have not had the need (obviously) to thread either nipples or spokes. I try not
    to make things that are easily (and more cheaply) purchased at the LBS.

    --
    Skuke Reverse the domain name to send email
     
  14. Chalo

    Chalo Guest

    [email protected] wrote:

    > I have not seen how they are made but I have seen spoke nipples that were forges to final shape
    > except for the screwdriver slot.

    Most spokes besides DT come furnished with nipples that are clearly swaged to form the square
    section. There is a telltale pillowy characteristic to the flats on these nipples, and I find that
    their somewhat rounded faces are more vulnerable to further rounding than are the machined type.

    Chalo Colina
     
  15. Mark Hickey

    Mark Hickey Guest

    skuke <[email protected]> wrote:

    >How on Earth did the bike industry wind up with that bastardization of a thread "standard"??

    Hey, the bike industry is the HOME of bastardized "standards" (that aren't). As soon as it can be
    conclusively determined that something works, it MUST be changed.

    Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame
     
  16. Chalo

    Chalo Guest

    skuke <[email protected]> wrote:

    > BTW, I do consider myself to be a cycling-centric machinist. I've made many custom component for
    > myself and others. I have not had the need (obviously) to thread either nipples or spokes. I try
    > not to make things that are easily (and more cheaply) purchased at the LBS.

    Amen to that.

    After building a bike for which I machined the hubs, front brakes, fork crown and steerer, stem,
    seatpost, bottom bracket, chainring spider and guards, and pump, I resolved to make do thereafter
    with commercially available components when they will do the job. Though commodity parts have fewer
    bragging rights attached, they are much cheaper in the big picture-- and easily replaceable.

    Chalo Colina
     
  17. On Mon, 23 Jun 2003 18:58:25 GMT, Mark Hickey <[email protected]> wrote:

    >Hey, the bike industry is the HOME of bastardized "standards" (that aren't). As soon as it can be
    >conclusively determined that something works, it MUST be changed.

    If you think the bicycle industry is the premier exhibitor of that effect, you've never
    worked in IT.

    Jasper
     
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