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Re: [SCA-Archery] Spine tester

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  • blooney@wi.rr.com
    Cian, According to the AMO (Archery Manufacturers Organization) Standard, the shaft deflection is measure in inches with shaft supported on 26 centers and
    Message 1 of 11 , Jan 12, 2007
      Cian,

      According to the AMO (Archery Manufacturers Organization) Standard,
      the shaft deflection is measure in inches with shaft supported on 26"
      centers and depressed with a two-pound weight. You should be able to
      rig something up w/ your gauge. I've attached the AMO chart that
      matches the deflection w/ the spine weight.

      William of Mann


      ----- Original Message -----
      From: Cian of Storvik <firespiter@...>
      Date: Friday, January 12, 2007 8:49 am
      Subject: [SCA-Archery] Spine tester
      To: SCA-Archery@yahoogroups.com

      > Does anyone have a plan to make an instrument to measure spine
      > weight?
      > I keep getting tempted to buy a spine tester. But the least
      > expensive one is almost $100.00. I have an out of round gauge
      > (mic)
      > and base. And I figure it's just a matter of putting two dowels in
      > a
      > board and mounting the mic on it.
      >
      > The cheap spine tester I've seen looks like it's 2 horizontal
      > dowels
      > that the arrow sits in. The first dowel; the arrow rests
      > underneath
      > just behind the pile. The second dowel appears to have the arrow
      > resting on top of it near the center-point of the arrow, and a
      > weight hangs off of the nock side making the arrow deflect, which
      > is
      > then measured with a compass gauge.
      >
      > What weight is placed on the arrow and at what distance? I believe
      > that spine = the compression force at which the arrow will deflect
      > 1". But how much deflection is this when using an ounce
      > measurement
      > to apply lateral force?
      >
      > In a related question, how much does a finish like tongue oil
      > affect
      > the spine weight of the arrow? I usually buy arrows "pre-spined"
      > and
      > wonder how much 3 or 4 liberal coats of tongue oil affects the
      > spine. (which is why I am interested in the spine tester to begin
      > with).
      >
      > -Cian
      >
      >


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