Primitive Archer
Main Discussion Area => Bows => Topic started by: tkdHayk on June 19, 2017, 02:53:46 pm
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So, one of my limbs on a 40 inch sinew backed bow has a slight deflex close to the handle. The deflex is Very slight. It will not cause any problems for me. However, I am curious what would happen if one limb was substantially deflexted while the other was reflexed? When such a bow is drawn, the reflexed limb needs to move further to visually appear the same as a straight or deflexed limb. Should one make the reflexed limb weaker in order to achieve a visually symmetrical tiller? Or should one make sure that the limbs are doing the same amount of work, even if it means that the tiller will not be visually symmetrical? Which is more important? Should one aim for visual symmetry, or work load balance? What factors should be considered?
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Making it look balanced at full draw.Stave bows are adjusted for balance pretty much all of the time.The main factor to me is how it shoots.Shooting it out of balance or not in tiller would not be good.The timing of each limb tip hitting home when the arrow left would be different and cause hand shock.
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well here are my 2 cents:
It essentiall if that deflex appered while shooting the bow or was it natural. In the first case it is a tiller let loose developing a hinge - not good! you have to bring that in line asap.
In the second case, the natural dflex: If it's me Iwould bring that in balance (before sinewing).
If you want to go with that natural imperfection, that thing would be visible in all profiles unbraced, braced, and fd.
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Rather than make it LOOK balanced at full draw, you should make it ACT balanced at full draw. A bow with limb shapes as you describe will not appear balanced as folks are accustomed to seeing, when they are in fact perfectly balanced relative to each other and the archer's holds. With the handle level, as they're drawn, one will stay ahead of the other, and they should each reflect some flexing semblence of their own unbraced profiles, yet will be dynamically balanced in strength so that when drawn on the rope and pulley type tillering tree, the arrow nock comes straight back and leaves straight away, being pulled in neither direction toward a stronger ACTING limb. This is how I tiller all bows, regardless of their limb profiles. It actually makes things a lot easier, straightforward, and there is no guesswork.
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Perfect explanation, Jeffro.
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Reminds me of the Andaman bows described in TBB4..3?
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Thanks for the responses guys, much appreciated.
What do you guys think about using dry heat to correct the slight deflex? Will the heat strengthen or weaken the wood fibers? The bow is a sine backed red oak board. I don't know how dry it is and don't want to risk making it too dry. and there is sinew on the other side, but it should not experience any heat gain if I use a heat gun on the belly. Good idea?
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well here are my 2 cents:
It essentiall if that deflex appered while shooting the bow or was it natural. In the first case it is a tiller let loose developing a hinge - not good! you have to bring that in line asap.
In the second case, the natural dflex: If it's me Iwould bring that in balance (before sinewing).
If you want to go with that natural imperfection, that thing would be visible in all profiles unbraced, braced, and fd.
I think this deflex was caused by the floor tillering process, so it is most likely set rather than natural curvature of the wood. however i could be wrong. It is very slight deflex but because its close to the handle, it translates half a centimeter of movement at the tip. Should I use a heat gun to correct this?
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Floor tillering should not cause any set unless the wood is wet.
Anyway, I agree with DWS.
To add...
The deflexed and reflexed limbs need to move the same when drawn to full draw.
You won't get that perfect tiller picture but the handle pressure as you draw the bow will be even.
Jawge