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How do you control or modify hand shock in an otherwise efficient bow
ssrhythm:
The idea mentioned that hand shock is due to the limbs returning to brace out of time…is certainly true. Too heavy limb tips cause shock…other aspects of the design do, I’m sure, as well. But limb return timing or limb synch certainly is a big factor.
I had my current build, a 35# @ 28” Osage longbow build for my son, well tillered with a dead even tiller. It is asymmetrical with 1.25” up from center and 2.75” down from center handle. I reduced the top limb to achieve a 1/8” positive tiller, as this is what I’ve read was necessary for this design to keep the shorter bottom limb from being overworked. There was no hand shock when the tiller was even, but that 1/8” positive tiller added a noticeable amount of shock.
It makes sense that a shorter, stronger bottom limb will return to brace more quickly than the longer, weaker top limb; it’s stronger and has less mass to move. It certainly contributes to the felt shock. I’m going to take the wisdom one sage poster suggested in my “bow-design” thread and adjust the length of my fades to yield equal length limbs on my next build while designing the handle in such a way that the bow string will be pulled as close to the center as possible…and I’m going for a neutral tiller.
I don’t think I addressed what you are asking, but it’s some good for thought.
Woodbear:
Thanks for the extended thoughts on de-vibrating my bow.
My usual hold on the bow is with the pressure point in the web of the hand between the base of the thumb and index finger, with my fingers lightly wrapped around the bow. I tried holding the fingers open and only closing on the bow to retain it after the shot. The vibration is actually felt more as I catch/retain the loose bow. In fact, a slightly tighter hold seemed to dampen the vibration more than the open hold. My other bows of similar length and tiller are heavier and require more pressure on the handle at full draw (forward push, not grip). Perhaps the lighter hand pressure on the lighter weight bow dampens vibration less?
Unfortunately, shifting the hand position up & down the handle in ˝ inch steps made no difference to the feel of vibration.
The B55 string is my concession to the modern world, mostly because I hate having to replace linen or hemp strings, and the B55 is practically indestructible. I also added otter fur silencers to the string. The otter fur quiets the string but not the bow handle vibration.
In my experience linen is less stretchy than B50, so I will have to give it another try.
I have been put off using DynaFlight / FastFlight etc. by the warnings against using it on wood bows. Can you guys give me your experience on DynaFlight 97 durability and how to protect a wood bow using it? It’s not primitive, but if I can tolerate B55 why not DF97?
Thanks for the thoughts on asymmetry and positive tiller. The bow is nominally absolutely symmetric, and the pressure point of the hand exactly central. The arrow pass in 15mm (0.60”) above center which is as close as I can get it to center. The bow has about 0.10” negative tiller mid limb at brace, but the full draw overlay shows positive “tiller” of 0.40”, so I went with that as the top limb. That said the vibration feels the same with the bow either way up, so I don’t think the positive/negative tiller is significant.
Dave
superdav95:
The d97 stuff is very good. It’s my go to for
Most of my bows with some exceptions. I stick with my b55 or sinew string for my composite horn bows. I did try to use some d97 on a 5
Piece horn bow build and found faster chrono speeds but not significantly faster. The b55 seemed to feel little better on the bow. Can’t explain it really. Maybe just the right amount of stretch?? Working on a sinew string for this bow now using natural tennis racket string. Will report on how it does when done.
superdav95:
--- Quote from: superdav95 on August 28, 2024, 11:10:19 pm ---The d97 stuff is very good. It’s my go to for
Most of my bows with some exceptions. I stick with my b55 or sinew string for my composite horn bows. I did try to use some d97 on a 5
Piece horn bow build and found faster chrono speeds but not significantly faster. The b55 seemed to feel little better on the bow. Can’t explain it really. Maybe just the right amount of stretch?? Working on a hog gut string for this bow now using natural tennis racket string. Will report on how it does when done.
--- End quote ---
ssrhythm:
The D97 worried me at first, as I don’t put tip overlays on my bow, and I try to make my tips narrow as possible…resulting in just a very thin area of back ring and not a lot of wood beneath the loop and between grooves. Despite my worries about D97 damaging the tips, it’s never been a problem. The added performance and crispness of the string is noticeable and worth it.
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