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Re: [7x10minilathe] Re: Weird thread

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  • Gregg Eshelman
    What make and model of 1970 s Japanese motorcycle is this weird thread on, and what part of it? ===== It will be total Fandemonium! Nampa Civic Center, August
    Message 1 of 17 , Dec 1, 2004
      What make and model of 1970's Japanese motorcycle
      is this weird thread on, and what part of it?

      =====
      It will be total Fandemonium!
      Nampa Civic Center, August 5th to August 7th, 2005!
      http://www.fandemonium.org



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    • gerry.waclawiak
      Not personally, but try the technical pages on this site www.tapdie.co.uk which are full of useful info on threads, tapping drills, equivalent sizes etc. Best
      Message 2 of 17 , Dec 1, 2004
        Not personally, but try the technical pages on this site
        www.tapdie.co.uk which are full of useful info on threads, tapping
        drills, equivalent sizes etc. Best of luck with your search!!

        Gerry
        Leeds
        UK

        -----Original Message-----
        From: Peter [mailto:crazypj10@...]
        Sent: 01 December 2004 04:40
        To: 7x10minilathe@yahoogroups.com
        Subject: [7x10minilathe] Re: Weird thread



        Hi Gerry,
        I hadnt thought of ME. do you have any details?
        PJ
        Transplant from South Wales to Florida

        --- In 7x10minilathe@yahoogroups.com, <gerry.waclawiak@n...> wrote:
        > Its not British BA or ME (Model engineering ) thread by any chance.
        BA is a wierd mix of metric diameter threads. A lot of the smaller ME
        taps use 32 and/or 40 tpi (3/16",1/4")
        >
        > Gerry
        > Leeds
        > UK








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      • zzz_zinger
        ... Peter, This is indeed an interesting thread - no pun intended. I have tried to do a little research and here is what I have come up with. The BSCy or
        Message 3 of 17 , Dec 1, 2004
          --- In 7x10minilathe@yahoogroups.com, "Peter" <crazypj10@y...> wrote:
          >
          > Because of the general consensus about 0.6mm pitch I re-checked.
          > the only pitch gauge that fits exactly over the entire half inch of
          > thread is Whitworth 40tpi(using a 5xloupe)but diameter is too big at
          > 0.1375" for 1/8th and thread angle is 55 not 60.
          > I guess its going to be one of the mysteries of life.
          > If I figure out a way to make a die I'll let you know ( I'm not going
          > to try and cut a thread inside a hole less than 0.120" dia!)
          > PJ

          Peter,
          This is indeed an interesting thread - no pun intended. I have tried
          to do a little research and here is what I have come up with.

          The BSCy or BSCycle (British Standard Cycle) at one time had small
          diameter taps/dies and the small ones seem to coincide with the swg
          sizes. For example, I have found that a 10swg is 0.128 nominal size
          with an actual O/D of 0.141 and a T.P.I. of 40. Recommended Tap drill
          size is 3.1mm and the Clearance drill size is 3.75mm.

          This size is a little larger than the standard 1/8 BSCy - 40 TPI that
          has a clearance drill size of 3.5mm.

          No specification on the thread angle for these sizes is mentioned.
          However, further research shows that the more modern sizes (ones
          currently offered for sale today) use a 60 degree thread angle but
          they no long show the sizes I quoted as being offered/available.

          The 9swg or nominal 0.144 BSCy - 40 TPI has an actual O/D of 0.157 and
          the tap drill size is 3.5mm with a clearance of 4.25mm.

          I managed to rule out the BSF, BSW, BSB, BSP, ME, BA, Metric and of
          course UNF & UNC. The best I could find close to your thread was the
          BSCy.

          The BSCycle is specifically designed for bicycles (late 1800's) and
          later motorcycles with characteristics to reduce loosening in a
          vibration environment. The larger sizes are popular today.

          I suspect that you have Japan's version of the same type thread
          described above with alterations as they so commonly did after WWII.

          Interesting researching this - it is remarkable what you can find on
          the web.
          Hope this is of some help.
          Jim-M
        • roylowenthal
          It doesn t match anything listed in Guide to World Screw Threads. I ve lost track of the original goal of this project; I assume you re trying to tap a hole.
          Message 4 of 17 , Dec 1, 2004
            It doesn't match anything listed in "Guide to World Screw Threads."

            I've lost track of the original goal of this project; I assume you're
            trying to tap a hole. You can make a "sort of" tap by threading an
            existing HSS round "something of suitable diameter" by using carbide
            tooling & forming grooves with an abrasive cut-off wheel. It's not a
            thing of beauty & the resulting threads will probably be a little
            ratty looking - its virtue is that it makes a workable fix.

            Roy

            --- In 7x10minilathe@yahoogroups.com, "Peter" <crazypj10@y...> wrote:
            >
            > Because of the general consensus about 0.6mm pitch I re-checked.
            > the only pitch gauge that fits exactly over the entire half inch of
            > thread is Whitworth 40tpi(using a 5xloupe)but diameter is too big
            at
            > 0.1375" for 1/8th and thread angle is 55 not 60.
            > I guess its going to be one of the mysteries of life.
            > If I figure out a way to make a die I'll let you know ( I'm not
            going
            > to try and cut a thread inside a hole less than 0.120" dia!)
            > PJ
            >
            >
            > > 3.5mm X 0.6 is a standard metric thread (although not frequently
            > > used). I just counted the points on my tap and 0.6 is 40 TPI.
          • lurch
            9/64-40 perhaps? what kind of bike is it off of? ... From: zzz_zinger [mailto:zipididude@cox.net] Sent: Wednesday, December 01, 2004 3:05 PM To:
            Message 5 of 17 , Dec 2, 2004
              9/64-40 perhaps?  what kind of bike is it off of?
              -----Original Message-----
              From: zzz_zinger [mailto:zipididude@...]
              Sent: Wednesday, December 01, 2004 3:05 PM
              To: 7x10minilathe@yahoogroups.com
              Subject: [7x10minilathe] Re: Weird thread


              --- In 7x10minilathe@yahoogroups.com, "Peter" <crazypj10@y...> wrote:
              >
              > Because of the general consensus about 0.6mm pitch I re-checked.
              > the only pitch gauge that fits exactly over the entire half inch of
              > thread is Whitworth 40tpi(using a 5xloupe)but diameter is too big at
              > 0.1375" for 1/8th and thread angle is 55 not 60.
              > I guess its going to be one of the mysteries of life.
              > If I figure out a way to make a die I'll let you know ( I'm not going
              > to try and cut a thread inside a hole less than 0.120" dia!)
              > PJ

              Peter,
              This is indeed an interesting thread - no pun intended.  I have tried
              to do a little research and here is what I have come up with.

              The BSCy or BSCycle (British Standard Cycle) at one time had small
              diameter taps/dies and the small ones seem to coincide with the swg
              sizes.  For example, I have found that a 10swg is 0.128 nominal size
              with an actual O/D of 0.141 and a T.P.I. of 40. Recommended Tap drill
              size is 3.1mm and the Clearance drill size is 3.75mm.

              This size is a little larger than the standard 1/8 BSCy - 40 TPI that
              has a clearance drill size of 3.5mm.

              No specification on the thread angle for these sizes is mentioned.
              However, further research shows that the more modern sizes (ones
              currently offered for sale today) use a 60 degree thread angle but
              they no long show the sizes I quoted as being offered/available.

              The 9swg or nominal 0.144 BSCy - 40 TPI has an actual O/D of 0.157 and
              the tap drill size is 3.5mm with a clearance of 4.25mm.

              I managed to rule out the BSF, BSW, BSB, BSP, ME, BA, Metric and of
              course UNF & UNC.  The best I could find close to your thread was the
              BSCy.

              The BSCycle is specifically designed for bicycles (late 1800's) and
              later motorcycles with characteristics to reduce loosening in a
              vibration environment.  The larger sizes are popular today.

              I suspect that you have Japan's version of the same type thread
              described above with alterations as they so commonly did after WWII.

              Interesting researching this - it is remarkable what you can find on
              the web.
              Hope this is of some help.
              Jim-M




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