Primitive Archer

Clint, I've been cutting firewood safely for over 50 years and a dead pine, not part of what I was cutting, took me down. You just never know. And even with the severity of this accident I was extremely lucky it wasn't worse than a scalp wound.

I'm glad it wasn't worse Pat.  Tree cutting accidents happen fast.  I've had some close calls with osage over the years but nothing anywhere near what happened to you

Pappy, I'm glad you are getting use out of that brain blaster.  It sure makes it easier to clean them.  Good to hear your better half is on the mend.  I'm going to try my best to make it to the Classic this coming year.  It's been too long.  Congratulations on the deer!

    Measuring stored energy is kind of a pain. But if you are interested in knowing where your energy is going it really is a necessity to get a fairly accurate reading of how much energy your bow stores. I am going to propose a simplified method for fairly accurate assessments. One person doesn't really make enough bows to supply enough data so I am asking the community here to help us out and see what we can come up with in a short amount of time. The method I am proposing involves taking one simple draw weight measurement at exactly one-half your draw stroke. Example: bow draws 50# @ 28", bow has a 6" brace height. So the power stroke is 22". So we measure 1/2 of the draw stroke plus brace height equals 17". This is where we measure the weight.

  If someone here knows excel they can track this for us and give us the data. Before I go into detail, I want to show what I am thinking it will produce.

   Measurement @ 1/2 draw,        Stored            SEPDF                 Backset              style         Bow Length
    50# bow, 28" draw                  Energy
   
                          22#                  40.3#              80.6%               -1"                   straight         65"
                          23#                  42.06               84.1%                -5"                  straight         64"
                          24#                  44.00               88.0%               0                      R/D              65"                     
                          25#                  45.80               91.6%               .5"                    R/d               67"
                          26#                  47.6                95.5%                 1"                   recurve          64"
                          27#                  49.5                 99%                   2"                     R/D              67"
                          28#                  51.3                 102%                 3"                     recurve         66"
                          29#                  53.1                 106.2%               3"                    R/d               74"
                          30#                  55#                  110%                 6"                      recurve        65"


    These are just theoretical examples of what I think it will look like. If we can get in about 100 samples from the crew here we could establish a credable data base to figure where we were at and what the different numbers might mean to an everyday bow maker.

  The info I will need is . Draw weight, #" at 1/2 draw.  bow length, style and back set. I will probably add some optional rows just for reference.

Spine does matter!
If you’ve ever shot a bare-shaft test, you know it absolutely matters. And using a bare-shaft test is the only reliable way to determine the correct arrow parameters—it immediately shows whether an arrow is dynamically correct, too weak, or too stiff.

The old rule of 5# per inch of arrow length applies only when the bow’s draw weight is around 65–75#. The rule was “created” by Saxton Pope, who shot bows in that range. For weaker bows, the rule simply doesn’t hold. In reality, the correlation is non-linear. For example, with 35–40# bows, the “rule” is roughly 2.5# per inch. And so on.

It’s also commonly assumed that a 28" arrow requires spine matching the bow weight—for example, a 30# bow needs a 30# arrow. But again, in practice this varies from archer to archer. One shooter may need 35# or even 40# arrows, while another may need 25# arrows for the same 30# bow. A bare shaft test will tell the truth.

The cut-in window has no effect. The required arrow spine is the same for wide-handle bows, narrow-handle bows, or windowed bows. If you don’t believe it, do a bare-shaft test using the same bow with different handle widths.

And finally, arrow point weight has almost no effect on required shaft spine. A 25-grain change influences spine by about 1# or less. Again—shoot a bare-shaft test to see for yourself!