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Re: [KnotTyers] Re: turks head calculators

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  • Lindsey Philpott
    Hi Douglas, Well, while I applaud your statements of accurate measurement which we should all find no fault with for accuracy, we are dealing with string here
    Message 1 of 12 , Sep 20, 2007
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      Hi Douglas,

      Well, while I applaud your statements of accurate measurement which we should all find no fault with for accuracy, we are dealing with string here and it is not beyond even the least reasonable person to interpret that it takes practice to find the true length of a TH knot, because each person will tighten the line to a different degree and may well reduce the thickness down even more than the original 1/8-inch thickness! Perhaps I should have been clearer about that, but I acknowledge my error in not having said so explicitly.

      To look again at your last example - I would challenge you to show me a TH knot made with 18 bights around a 2-inch dowel and having three passes and 5 leads (are you calling leads as parts where I am using the letter P to mean passes or am I much mistaken?) using a 1/8-inch cord. The practical side of things makes a difference, which in this case results in 1/8-inch line making bends of 0.349-inches (max.) and each bend inside of the outer one will be 0.125-inches less, meaning that the inside pass of the three passes will be folded over itself - and I haven't even allowed for the thickness of one line crossing another - for all the number-crunchers out there, this doesn't make sense to me. Have I missed some obvious fact?

      Otherwise - excellent advice would be, as Lily has expressed it (thanks Lily), practice makes perfect!

      Douglas Varney <varney@...> wrote:
      --- In knottyers@yahoogroups.com, Lindsey Philpott
      <pilgrimsailor@...> wrote:
      >
      > Hi Howard,
      >
      If you just want a formula to work out a simple Turk's Head use
      this:
      >
      > 22/7 * D * L * P * 1.15
      >
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      The equation above will give reasonable accuracy for square THs and
      for Long THs that incorporate a large diameter and/or a small number
      of bights. It neglects the effect of cordage diameter especially
      important if you are making multiple passes.
      As long as the circumference is large relative to these factors then
      the equation will give decent results.

      For the 7pX5b with a diameter of 4 inches and a cordage diameter of
      O.125 inches the follow data is:
      # of passes Length from equation above Actual Length Diff
      1 101 88 +15%
      2 202 179 +13%
      3 303 276 +18%

      For the 5pX18b with a diameter of 4 inches and a cordage diameter of
      O.125 inches the follow data is:
      # of passes Length from equation above Actual Length Diff
      1 72 67 +7%
      2 124 157 -27%
      3 216 284 -31%

      The problem even becomes more pronounced when the diameter is reduce
      to 2 inches and everything else held constant
      # of passes Length from equation above Actual Length Diff
      1 36 39 -8%
      2 72 113 -57%
      3 108 232 -115%

      You can see that by not considering the number of bights and the
      diameter of the cordage can lead to a signifigant cordage shortage.

      I am not sure if the other operating systems ike MAC have EXCEL
      available to them but I have an EXCEL program in the "FILES" on this
      forum that will compute the lengh of cordage necessary to tie a TH.

      Regards,
      knotworkn







      Lindsey
      Board Member IGKTPAB


      [Non-text portions of this message have been removed]
    • jchamml
      My Javascript turks head calculator has moved to here: http://turkshead.50webs.org/ I tie them by printing off T.J. Bartruff s crossing chart found here:
      Message 2 of 12 , Sep 20, 2007
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        My Javascript turks head calculator has moved to here:
        http://turkshead.50webs.org/
        I tie them by printing off T.J. Bartruff's crossing chart found here:
        http://www.folsoms.net/knots/tejay/index.htm
        (after cropping and sizing as necessary with irfanview)
        roll it up into a tube and tape, stuff it with pillow poly, and start
        pinning the cord down.
      • KnotHead
        AMEN to that bro... ... From: Lindsey Philpott To: knottyers@yahoogroups.com Sent: Thursday, September 20, 2007 6:29 PM Subject: Re: [KnotTyers] Re: turks head
        Message 3 of 12 , Sep 20, 2007
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          AMEN to that bro...

          ----- Original Message -----
          From: Lindsey Philpott
          To: knottyers@yahoogroups.com
          Sent: Thursday, September 20, 2007 6:29 PM
          Subject: Re: [KnotTyers] Re: turks head calculators


          Hi Douglas,

          Well, while I applaud your statements of accurate measurement which we should all find no fault with for accuracy, we are dealing with string here and it is not beyond even the least reasonable person to interpret that it takes practice to find the true length of a TH knot, because each person will tighten the line to a different degree and may well reduce the thickness down even more than the original 1/8-inch thickness! Perhaps I should have been clearer about that, but I acknowledge my error in not having said so explicitly.

          To look again at your last example - I would challenge you to show me a TH knot made with 18 bights around a 2-inch dowel and having three passes and 5 leads (are you calling leads as parts where I am using the letter P to mean passes or am I much mistaken?) using a 1/8-inch cord. The practical side of things makes a difference, which in this case results in 1/8-inch line making bends of 0.349-inches (max.) and each bend inside of the outer one will be 0.125-inches less, meaning that the inside pass of the three passes will be folded over itself - and I haven't even allowed for the thickness of one line crossing another - for all the number-crunchers out there, this doesn't make sense to me. Have I missed some obvious fact?

          Otherwise - excellent advice would be, as Lily has expressed it (thanks Lily), practice makes perfect!

          Douglas Varney <varney@...> wrote:
          --- In knottyers@yahoogroups.com, Lindsey Philpott
          <pilgrimsailor@...> wrote:
          >
          > Hi Howard,
          >
          If you just want a formula to work out a simple Turk's Head use
          this:
          >
          > 22/7 * D * L * P * 1.15
          >
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
          The equation above will give reasonable accuracy for square THs and
          for Long THs that incorporate a large diameter and/or a small number
          of bights. It neglects the effect of cordage diameter especially
          important if you are making multiple passes.
          As long as the circumference is large relative to these factors then
          the equation will give decent results.

          For the 7pX5b with a diameter of 4 inches and a cordage diameter of
          O.125 inches the follow data is:
          # of passes Length from equation above Actual Length Diff
          1 101 88 +15%
          2 202 179 +13%
          3 303 276 +18%

          For the 5pX18b with a diameter of 4 inches and a cordage diameter of
          O.125 inches the follow data is:
          # of passes Length from equation above Actual Length Diff
          1 72 67 +7%
          2 124 157 -27%
          3 216 284 -31%

          The problem even becomes more pronounced when the diameter is reduce
          to 2 inches and everything else held constant
          # of passes Length from equation above Actual Length Diff
          1 36 39 -8%
          2 72 113 -57%
          3 108 232 -115%

          You can see that by not considering the number of bights and the
          diameter of the cordage can lead to a signifigant cordage shortage.

          I am not sure if the other operating systems ike MAC have EXCEL
          available to them but I have an EXCEL program in the "FILES" on this
          forum that will compute the lengh of cordage necessary to tie a TH.

          Regards,
          knotworkn

          Lindsey
          Board Member IGKTPAB

          [Non-text portions of this message have been removed]





          [Non-text portions of this message have been removed]
        • Dave Hedgepeth
          String is cheap here so I don t worry how much I used. I ve done projects while at sea where I could not get anymore string and pulled it through in one
          Message 4 of 12 , Sep 21, 2007
          • 0 Attachment
            String is cheap here so I don't worry how much I used. I've done projects while at sea where I could not get anymore string and pulled it through in one direction to recapture the slack.

            Dave

            Lindsey Philpott <pilgrimsailor@...> wrote:
            Hi Douglas,

            Well, while I applaud your statements of accurate measurement which we should all find no fault with for accuracy, we are dealing with string here and it is not beyond even the least reasonable person to interpret that it takes practice to find the true length of a TH knot, because each person will tighten the line to a different degree and may well reduce the thickness down even more than the original 1/8-inch thickness! Perhaps I should have been clearer about that, but I acknowledge my error in not having said so explicitly.

            To look again at your last example - I would challenge you to show me a TH knot made with 18 bights around a 2-inch dowel and having three passes and 5 leads (are you calling leads as parts where I am using the letter P to mean passes or am I much mistaken?) using a 1/8-inch cord. The practical side of things makes a difference, which in this case results in 1/8-inch line making bends of 0.349-inches (max.) and each bend inside of the outer one will be 0.125-inches less, meaning that the inside pass of the three passes will be folded over itself - and I haven't even allowed for the thickness of one line crossing another - for all the number-crunchers out there, this doesn't make sense to me. Have I missed some obvious fact?

            Otherwise - excellent advice would be, as Lily has expressed it (thanks Lily), practice makes perfect!

            Douglas Varney <varney@...> wrote:
            --- In knottyers@yahoogroups.com, Lindsey Philpott
            <pilgrimsailor@...> wrote:
            >
            > Hi Howard,
            >
            If you just want a formula to work out a simple Turk's Head use
            this:
            >
            > 22/7 * D * L * P * 1.15
            >
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            The equation above will give reasonable accuracy for square THs and
            for Long THs that incorporate a large diameter and/or a small number
            of bights. It neglects the effect of cordage diameter especially
            important if you are making multiple passes.
            As long as the circumference is large relative to these factors then
            the equation will give decent results.

            For the 7pX5b with a diameter of 4 inches and a cordage diameter of
            O.125 inches the follow data is:
            # of passes Length from equation above Actual Length Diff
            1 101 88 +15%
            2 202 179 +13%
            3 303 276 +18%

            For the 5pX18b with a diameter of 4 inches and a cordage diameter of
            O.125 inches the follow data is:
            # of passes Length from equation above Actual Length Diff
            1 72 67 +7%
            2 124 157 -27%
            3 216 284 -31%

            The problem even becomes more pronounced when the diameter is reduce
            to 2 inches and everything else held constant
            # of passes Length from equation above Actual Length Diff
            1 36 39 -8%
            2 72 113 -57%
            3 108 232 -115%

            You can see that by not considering the number of bights and the
            diameter of the cordage can lead to a signifigant cordage shortage.

            I am not sure if the other operating systems ike MAC have EXCEL
            available to them but I have an EXCEL program in the "FILES" on this
            forum that will compute the lengh of cordage necessary to tie a TH.

            Regards,
            knotworkn

            Lindsey
            Board Member IGKTPAB

            [Non-text portions of this message have been removed]






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