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bow weight

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  • John edgerton
    There is a general formula for estimating the increase of bow draw weight for an increase in thickness or in width. At the moment I can neither remember it or
    Message 1 of 6 , Jun 3, 2005
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      There is a general formula for estimating the increase of bow draw
      weight for an increase in thickness or in width. At the moment I can
      neither remember it or find a reference to it in my books. Could
      someone please post it?

      Thanks for any help you can give.

      Jon
    • Eadric Anstapa
      It depends almost entirely on the materials used to construct the bow. You can find various references for lemonwood or yew or osage or .... that are all a
      Message 2 of 6 , Jun 3, 2005
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        It depends almost entirely on the materials used to construct the
        bow.

        You can find various references for lemonwood or yew or osage
        or .... that are all a little different. Of course laminiated
        bows of either wood, horn or synthetic laminates change all of
        that.

        And of course the design of the bow also matters. A bow that has
        radical reflex/deflex/recurve action or a bow with siyahs or a
        longbow will all be different. But any one design should have a
        pretty linear increase in draw weight.

        Regards,

        -EA
        (who is in Europe visiting museums at the moment. Saw a real
        several thousand year old Holmegard style bow in a museum today)

        John edgerton <sirjon1@...> said:

        > There is a general formula for estimating the increase of bow
        draw
        > weight for an increase in thickness or in width. At the moment I
        can
        > neither remember it or find a reference to it in my books.
        Could
        > someone please post it?
        >
        > Thanks for any help you can give.
        >
        > Jon
        >
        >
        >
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        eadric@...
      • Kinjal of Moravia
        ... I believe you will find that when ordering a horsebow for a specified draw weight that the bow doesn t change at all -- only the size and number of the
        Message 3 of 6 , Jun 3, 2005
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          --- In SCA-Archery@yahoogroups.com, "Eadric Anstapa" <smills@s...>
          wrote:
          > It depends almost entirely on the materials used to construct the
          > bow.
          > .................................................................

          I believe you will find that when ordering a horsebow for a specified
          draw weight that the bow doesn't change at all -- only the size and
          number of the sinew (possibly artificial) strands inlaid under the
          outer skin -- that a 60# bow is no 'thicker' that a 35# one. It is
          sort of like adding a leaf spring to your truck suspension rather than
          changing the thickness of the main spring.

          kinjal
          >
        • jameswolfden
          The difference in thickness between a 60 pound bow and 35 pound is minimal regardless of bow type. This is one of the reasons why many first time bowyers end
          Message 4 of 6 , Jun 4, 2005
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            The difference in thickness between a 60 pound bow and 35
            pound is minimal regardless of bow type. This is one of the
            reasons why many first time bowyers end up building bows far
            lighter than they planned.

            The poundage is usually controlled by the width of the limbs
            rather than the thickness of the limbs as it is less sensitive. The
            rule of thumb is that doubling the width will make a bow twice as
            strong while doubling the thickness will make a bow 8x as
            strong.

            If I add another layer of sinew, I am changing the thickness of the
            bow. Typically, you will want the thickness of the sinew layers to
            equal the thickness of the horn layer. The horn layer can be
            gently scraped to drop poundage although some modern
            bowyers will preshape the core wood before laminating based
            on their experience.

            James Wolfden

            --- In SCA-Archery@yahoogroups.com, "Kinjal of Moravia"
            <gusarimagic@c...> wrote:
            > --- In SCA-Archery@yahoogroups.com, "Eadric Anstapa"
            <smills@s...>
            > wrote:
            > > It depends almost entirely on the materials used to construct
            the
            > > bow.
            > > .................................................................
            >
            > I believe you will find that when ordering a horsebow for a
            specified
            > draw weight that the bow doesn't change at all -- only the size
            and
            > number of the sinew (possibly artificial) strands inlaid under
            the
            > outer skin -- that a 60# bow is no 'thicker' that a 35# one. It is
            > sort of like adding a leaf spring to your truck suspension rather
            than
            > changing the thickness of the main spring.
            >
            > kinjal
            > >
          • John edgerton
            Thank you. That was the rule of thumb that I had read and heard before. But, just could not get my feeble olde brain to remember. Jon
            Message 5 of 6 , Jun 4, 2005
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              Thank you. That was the rule of thumb that I had read and heard
              before. But, just could not get my feeble olde brain to remember.

              Jon
              On Saturday, June 4, 2005, at 12:06 PM, jameswolfden wrote:

              > The difference in thickness between a 60 pound bow and 35
              > pound is minimal regardless of bow type. This is one of the
              > reasons why many first time bowyers end up building bows far
              > lighter than they planned.
              >
              > The poundage is usually controlled by the width of the limbs
              > rather than the thickness of the limbs as it is less sensitive. The
              > rule of thumb is that doubling the width will make a bow twice as
              > strong while doubling the thickness will make a bow 8x as
              > strong.
              >
              > If I add another layer of sinew, I am changing the thickness of the
              > bow. Typically, you will want the thickness of the sinew layers to
              > equal the thickness of the horn layer. The horn layer can be
              > gently scraped to drop poundage although some modern
              > bowyers will preshape the core wood before laminating based
              > on their experience.
              >
              > James Wolfden
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