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While having a little trouble getting perfect arrow flight with my new to me Border Black Douglas, I was involved in a conversation with Sid Sr. at Border archery about what was going on with my new bow. He offered some great comments on how hand placement affects the way a bow shoots. He said it would be fine to post our email communication on TT. I think its some great info and hope you folks get as much out of the discussion as I did. Here's the email:

"This bow was probably made for someone intending to shoot with three under and therefor zero balance. Nock point height is a function of many factors arrow spine for one. Weak arrows will not jump as high or as far left as a stiff shaft will (RH shooter) and so different spines will require a nock height alteration. Arrows with exaggerated FOC heavy point weights again the ability of the arrow to jump off the rest up and left (RH shooter) is reduced reducing nock point height and then again there is shooting technique how the archer actually shoots the bow. The geometry of the bow and the balance is already set in the bow design.

The convention is even tiller or up to 1/8” for three under. However I have shot bows of neutral and normal balance and apart from a small nock height change really did not notice any big difference.

With shooting technique what happens is that depending on how and where you pressurize the bow grip surface, straight wrist (high on the grip) or heel down (low on the grip), you alter the pressure on the limbs. If you go for a seriously high grip placing all the hand pressure high in the throat of the grip you tend to pull the top limb too far back and consequentially if you heel the grip (pressurize the lower part of the grip closer to your wrist) then the bottom limb comes back too much (this is more common especially in those who prefer low grips) So to see what is happening in reality exaggerate the action, actually grip the bow below the bow grip (exaggeratedly low) now pull the string from your normal nock point height and look at the bow profile in a mirror. You will notice that the angle between the string and limb on the top limb is less than that of the bottom limb the bottom limb is more open it has been drawn back farther than the top in this instance. If you were to shoot the bow like this then on release the string would start to wrap the top recurve first and the shot sequence would end with the string having full wrapped on the top with the bottom recurve still wrapping string. This has two issues to it. Firstly it sets up a massive vibration in the after shot sequence as the limbs are seesawing against each other wrapping string and unwrapping as the vibrations come to a stop. Top limb going forward then going back as the bottom wraps that then being pulled back again as the other limb goes forward again. Okay the second issue is that when the bottom limb is going forward as the top limbs starts to come back the very first cycle from release as the arrow leaves the string, the string is unwrapping on the top limb and wrapping on the bottom limb your nock height is on a downward path and you would have an exceptionally nock point height in order to try and compensate for this shooting error. If the top limb was being pulled back farther then the opposite would happen. You want this balanced and horizontal nock travel if possible or as close to that as possible and adjust nock height to compensate the small difference

Bows are generally set up with the arrow higher than the bow centre and this affects how far the limbs are being pulled one compared to the other. Ideally you want both limbs coming back evenly symmetrically with string to limb angle as close to equal on both limbs. So the bottom limb is made stronger this then forces the top limb to come back evenly or as close to even as can be managed and compensates for the off centre position of the arrow and draw-hand position and the fact that the bow hand pressure is generally below the centre of the bow.

So there is a sweet spot on the grip that balances the bow and as an archer it is your job to find that. It depends on how the bowyer set and tillered the limb balance, the actual position of the grip in the bow relative to limb balance and bow centre, changing the point on the grip that you pressurize with you bow hand to better balance the limbs until vibrations are at a minimum. There will always be some limb vibrations as you do have a string that has some elasticity and so stretches and shrinks due to the loadings placed on it because of the shot process. Spectra or Dyneema stretches approx. 3.5% until failure occurs. On a 60” string this would be equal to approx. 2” of elastic stretch.

With this in mind you need to experiment with your bow hand position and where and how your bow hand actually pushes the bow. As said you are trying to find that combination that enables the bow limbs equally drawn back (string angles between limbs are string as close to equal as possible) This will give the knock path as close a path to horizontal as possible and as low a nock height as possible.

However having said that the actual nock height is also dependent on other issues as well and what is most important is that the point of the arrow is in a harmonious position relative to the nock as possible at the point of nock separation from the string. Whatever nock height to achieve that is what is most important

Hope that this helps
Best regards
Sid
 
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