Which thread gauge should I buy?

Discussion in 'Cycling Equipment' started by Adam Rush, Feb 2, 2006.

  1. Adam Rush

    Adam Rush Guest

    I'm going to need to identify some threading on a bicycle soon, and I
    was wondering, which inch-thread system should I be looking out for.
    The only gauge I've seen which specifically mentioned which system it
    uses was for Whitworth threads.
     
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  2. spin156

    spin156 Guest

    Adam Rush wrote:
    > I'm going to need to identify some threading on a bicycle soon, and I
    > was wondering, which inch-thread system should I be looking out for.
    > The only gauge I've seen which specifically mentioned which system it
    > uses was for Whitworth threads.


    Are you talking about thread pitch gauges, or screw pitch gauges?
    If so, check out my reply in this thread:

    http://groups.google.com/group/rec....ae07d1aa2d9/24c6e21d77755194#24c6e21d77755194

    I give some reference sources and options for obtaining the gauges.

    Cheers,
    Bill
     
  3. Adam Rush

    Adam Rush Guest

    You confused me there for a minute; the link went to one of G.
    Daniels's posts :)

    I guess what I'm looking for is a thread pitch gauge. There are
    several models of inch-based thread pitch gauges for sale here. The
    systems they claim to use are:

    Whitworth
    UNF
    UNC

    Which of these would I want to buy? My bicycle is an old (WWII)
    Swedish roadster and could concievably have some English specifications
    in it. Also, what on earth is UNF/UNC? Are one of those BSA or SAE?
     
  4. Adam Rush writes:

    > I'm going to need to identify some threading on a bicycle soon, and
    > I was wondering, which inch-thread system should I be looking out
    > for. The only gauge I've seen which specifically mentioned which
    > system it uses was for Whitworth threads.


    Here is the most common and versatile thread gauge:

    http://www.generaltools.com/product.asp?action=prdupc&part=251

    Jobst Brandt
     
  5. spin156

    spin156 Guest

    Adam Rush wrote:
    > You confused me there for a minute; the link went to one of G.
    > Daniels's posts :)
    >
    > I guess what I'm looking for is a thread pitch gauge. There are
    > several models of inch-based thread pitch gauges for sale here. The
    > systems they claim to use are:
    >
    > Whitworth
    > UNF
    > UNC
    >
    > Which of these would I want to buy? My bicycle is an old (WWII)
    > Swedish roadster and could concievably have some English specifications
    > in it. Also, what on earth is UNF/UNC? Are one of those BSA or SAE?


    Sorry, I guess I should have just quoted myself. I meant that you
    need to find my posting (="spin156") in that thread. In that post
    I list a couple of links to thread pitch gauges.

    I have a couple from Starrett Tool myself, and the one Jobst shows are
    very nice. Other than metric and English, the other standard that I
    know of (from working on old MGs, and Rovers) is what I was told is
    "British Standard". An old car mechanic told me about British
    Standard (which he explained is measured in tenths of inches) after I
    complained about neither metric nor English wrenches working (i.e. many
    rounded-off nuts and bolt heads). I don't think it's used anymore.
    Hopefully, I got that all right. Maybe that's what you have
    (???).
     
  6. spin156

    spin156 Guest

    Adam Rush wrote:
    > You confused me there for a minute; the link went to one of G.
    > Daniels's posts :)
    >
    > I guess what I'm looking for is a thread pitch gauge. There are
    > several models of inch-based thread pitch gauges for sale here. The
    > systems they claim to use are:
    >
    > Whitworth
    > UNF
    > UNC
    >
    > Which of these would I want to buy? My bicycle is an old (WWII)
    > Swedish roadster and could concievably have some English specifications
    > in it. Also, what on earth is UNF/UNC? Are one of those BSA or SAE?


    Hi Adam,
    I found a page that explains the history of British thread types
    (including all that you have listed):

    http://www.enginehistory.org/british_fasteners.htm

    Hope this helps ;-)

    Cheers,
    Bill
     
  7. Leo Lichtman

    Leo Lichtman Guest

    "Adam Rush" wrote: (clip) what on earth is UNF/UNC? Are one of those BSA
    or SAE?
    ^^^^^^^^^^^^^^^^
    I don't know about the "U," but NF is national fine, and NC is national
    coarse. NF is the same as SAE.
     
  8. Adam Rush writes:

    > Whitworth
    > UNF
    > UNC


    > Which of these would I want to buy? My bicycle is an old (WWII)
    > Swedish roadster and could conceivably have some English specifications
    > in it. Also, what on earth is UNF/UNC? Are one of those BSA or SAE?


    Unified National Coarse/Fine back when everyone had his own thread type.
    1/4-20 and 1/4-28 or 4-40 and 4-48 are examples of the coarse and fine
    threads given in TPI or Threads Per Inch.

    I would expect a Swedish bicycle to have metric thread but then
    bicycles have always been "different" as in:

    --------------------------------

    The four kinds of BB threads in common use today are Italian, British,
    French, and Swiss, possibly in that order of occurrence.

    Diameter Pitch Right Left Cup
    -------- ----- ----- -----
    Italian 36mm x 24F TPI right right TPI (threads per inch)
    British 1.370" x 24F TPI left right
    French 35mm x 1mm right right
    Swiss 35mm x 1mm left right

    --------------------------------



    Jobst Brandt
     
  9. A Muzi

    A Muzi Guest

    Adam Rush wrote:
    > I'm going to need to identify some threading on a bicycle soon, and I
    > was wondering, which inch-thread system should I be looking out for.
    > The only gauge I've seen which specifically mentioned which system it
    > uses was for Whitworth threads.


    That gauge is mostly useful to Raleigh & other vintage UK
    bikes and the Roadster clones of Asia.
    If you can only get the WW model it is still useful on SAE
    threads and covers our common 24, 26, 28 tpi. Even with the
    difference of form a WW gauge is plenty accurate to tell a
    24 from a 26.

    Look for one with SAE and metric, which the French snootily
    call "SI".
    In standard DIN metric for example a 5mm bolt has a pitch of
    0.8 with an 8mm wrench flat. The French version is 0.9 with
    a 9mm wrench. Some "system internationale", eh?

    When you say "need to identify some threading on a bicycle"
    which threads? For many problems a thread gauge isn't all
    that useful. For axle sets it surely helps.
    --
    Andrew Muzi
    www.yellowjersey.org
    Open every day since 1 April, 1971
     
  10. [email protected] wrote:
    > http://cratepro.com/


    Gene is joining the ranks of Florida homebuilders, apparently.

    > en.wikipedia.org/wiki/Linseed_oil


    To avoid cutting and pasting:
    <http://en.wikipedia.org/wiki/Linseed_oil>.

    >From the article; "Bicycle Repair thread fixative for spoked bicycle

    wheels". Time for Trevor Jeffrey to contribute an article. ;)

    --
    Tom Sherman - Fox River Valley
     
  11. john

    john Guest

    >Are you talking about thread pitch gauges, or screw pitch gauges?

    There's a difference between thread pitch gauges, and screw pitch
    gauges? This is something very new to me & I've been working w/ nuts &
    bolts & threads for over 40 yrs. Could please elaborate?

    Thanks, John
     
  12. Adam Rush

    Adam Rush Guest

    > That gauge is mostly useful to Raleigh & other vintage UK
    > bikes and the Roadster clones of Asia.
    > If you can only get the WW model it is still useful on SAE
    > threads and covers our common 24, 26, 28 tpi. Even with the
    > difference of form a WW gauge is plenty accurate to tell a
    > 24 from a 26.


    Okay, that's really good to know. What is the least painful way to
    measure diameter?

    > Look for one with SAE and metric, which the French snootily
    > call "SI".
    >
    > In standard DIN metric for example a 5mm bolt has a pitch of
    > 0.8 with an 8mm wrench flat. The French version is 0.9 with
    > a 9mm wrench. Some "system internationale", eh?


    Wow.

    > When you say "need to identify some threading on a bicycle"
    > which threads? For many problems a thread gauge isn't all
    > that useful. For axle sets it surely helps.


    I'm getting an old Swedish army bicycle soon and would like to make an
    online guide to its maintenance. The problem is that, at that point in
    time, there is no telling which threading standard(s) they used, and
    the documentation is quite hard to come by. It could be any threading
    system, really, except for the American ones. I'm looking to identify
    all of the threads.
     
  13. spin156

    spin156 Guest

    Adam Rush wrote:
    > > That gauge is mostly useful to Raleigh & other vintage UK
    > > bikes and the Roadster clones of Asia.
    > > If you can only get the WW model it is still useful on SAE
    > > threads and covers our common 24, 26, 28 tpi. Even with the
    > > difference of form a WW gauge is plenty accurate to tell a
    > > 24 from a 26.

    >
    > Okay, that's really good to know. What is the least painful way to
    > measure diameter?
    >

    Calipers. Dial calipers are good, digital are better (plus you can
    toggle
    between metric and English with most of them).

    > > Look for one with SAE and metric, which the French snootily
    > > call "SI".
    > >
    > > In standard DIN metric for example a 5mm bolt has a pitch of
    > > 0.8 with an 8mm wrench flat. The French version is 0.9 with
    > > a 9mm wrench. Some "system internationale", eh?

    >
    > Wow.
    >
    > > When you say "need to identify some threading on a bicycle"
    > > which threads? For many problems a thread gauge isn't all
    > > that useful. For axle sets it surely helps.

    >
    > I'm getting an old Swedish army bicycle soon and would like to make an
    > online guide to its maintenance. The problem is that, at that point in
    > time, there is no telling which threading standard(s) they used, and
    > the documentation is quite hard to come by. It could be any threading
    > system, really, except for the American ones. I'm looking to identify
    > all of the threads.


    Adam, when I gave you my earlier answer, I just googled [Whitworth UNC
    UNF].
    It came back with pages and pages of reference sites. If you do
    this you
    are bound to find what you are looking for.

    I have spent most of my life building engineering prototypes for
    electromechanical
    devices and, as a result, have spent a lot of time working with
    machinists. When you give them an unknown threaded device they do
    two things. First, they break out the calipers and measure the
    diameter (O.D. for screws/axles/etc, and I.D. for nuts and the like),
    and then they break out the thread pitch gauge and check the thread.
    Measuring a diameter can be ambiguous, as to whether it's metric or
    English, but thread pitches don't lie. Some the older British types
    have different angles to the threads themselves and any decent
    machinist is going to see this right away.
     
  14. Chalo

    Chalo Guest

    Leo Lichtman wrote:
    >
    > "Adam Rush" wrote: (clip) what on earth is UNF/UNC? Are one of those BSA
    > or SAE?
    > ^^^^^^^^^^^^^^^^
    > I don't know about the "U," but NF is national fine, and NC is national
    > coarse. NF is the same as SAE.


    And NC is the same as USS.

    Chalo
     
  15. Chalo

    Chalo Guest

    spin156 wrote:
    >
    > Adam Rush wrote:
    > >
    > > Okay, that's really good to know. What is the least painful way to
    > > measure diameter?
    > >

    > Calipers. Dial calipers are good, digital are better (plus you can
    > toggle between metric and English with most of them).


    Dial calipers don't toggle units. ;^)

    Note that most fasteners run undersized to the order of .005" or .1mm
    beneath their nominal diameter. This can cause some confusion when
    trying to distinguish close equivaments, e.g. 8mm and 5/16".

    > First, they break out the calipers and measure the
    > diameter (O.D. for screws/axles/etc, and I.D. for nuts and the like),
    > and then they break out the thread pitch gauge and check the thread.
    > Measuring a diameter can be ambiguous, as to whether it's metric or
    > English, but thread pitches don't lie.


    That's the ticket. It's often possible to improvise without a pitch
    gauge if you have a decent caliper, by measuring peak to peak across a
    known number of threads and then doing the arithemetic-- but a pitch
    gauge is easier and more determinate.

    Chalo Colina
     
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