Primitive Archer
Main Discussion Area => Bows => Topic started by: redhillwoods on January 16, 2018, 09:12:18 am
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What are the contributing factors/causes of handshock and string vibration after the arrow leaves the bow?
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IMO, and in no particular order.
Arrow too light.
Brace height too low.
Poor tiller.
Insufficient twists in bow sting when "hard" string is used,
Uncomfortable grip, gives the feel of hand shock, even though it's just a normal bow.
Anvils tied to ends of limbs
Del
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x2
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Tiller will be the culprit most often. Using heavier arrows is just putting make up on a pig. If a bow requires heavy arrows to feel good, something is wrong, IMO.
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Tiller will be the culprit most often. Using heavier arrows is just putting make up on a pig. If a bow requires heavy arrows to feel good, something is wrong, IMO.
Yeah, but you do get some newbies shooting 5/16 target arrows from an 80+ pounder... ::) (Esp in UK where we don't have hunting weight arrows)
Bit like these modern target archers with recurves and compounds with lightweight carbon arrows who are striving for ever increasing arrow speed and then have to screw 3 tons of stabilizers and silencers on to try to calm it down ::)
I notice it when shooting in bows over about 60#, I need to go up to 11/32" shafts, more for the weight than the spine.
Del
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That's a good point. Our world is mostly a hunting world and yours is mostly a flight world. I struggle to make an arrow under 525 grains for my draw length and a 50# bow. Regardless of what materials I use.
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I think Tiller is the biggest single culprit assuming reasonable sized outer limbs. My thoughts are that perfectly round tillers are bad for handshock. We shoot 150 and 200 grain arrows from 50 and 60# bows with no handshock. A few years ago I played around using the Gizmo on several bows. All of a sudden my bows had handshock and the tillers looked perfect. I still use the gizmo up to about 22" and then I switch to eyeball. About 10 years ago I built a 60# 69" osage elb. The tiller was as perfect as I have ever gotten one. The first shot out of the bow my hand felt like it was broken. After about 5 shots I couldn't use my hand for a week. I took it home and dropped it down to 50# making the tiller more elyptical and the shock all but went away.
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as badger alluded to, if the tips have too much mass. do you have a handshocky bow? post pics unbraced, braced , fulldraw,front profile
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Wide/"fat" tips don't cause hand shock. I would have argued otherwise years ago. Now, I know better.
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I think dynamic limb imbalance is usually the root cause, and things like extra mass on the tips, less mass in the handle, bendy handles, light arrows, lower brace heights, and such do more exacerbate it than create it themselves.
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pearl, can you elaborate on how too much tip mass does not cause handshock?
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When the limb design and tiller match a little extra tip width means nothing. I have shot tons and tons and tons of bows. Some had 1/4" wide tips and some had 3/4" plus wide tips and when the tiller matched the profile the bows shot just fine. I've shot bows that had super narrow tips and rattled fillings loose because the tillers sucked. Gary Davis is a fine example. Quite often his tips are twice the width I go for, and his bows shoot just dandy. Like Jeff said, extra tip mass can become an issue when there are underlying issues, the tips just amplify something else that is wrong. Limb balance, as Jeff pointed out, is a prime factor. Adding more weigh to something already out of balance just makes it worse.
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I personally feel that extra tip mass affects speed more than handshock.
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Limb timing and tiller style.
In addition to the tillering tree I trace one limb at brace then flip to see that both sides match. Iff it's off it will be slower and most likely have unnecessary hand shock. Probably not a useful method on a bow with lots of character.
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thanks, pearl
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About 10 years ago I built a 60# 69" osage elb. The tiller was as perfect as I have ever gotten one. The first shot out of the bow my hand felt like it was broken. After about 5 shots I couldn't use my hand for a week. I took it home and dropped it down to 50# making the tiller more elyptical and the shock all but went away.
I am guessing that not all that much wood was removed, to be able to blame "excess mass" for the initial cause.
nor would think that uneven tiller was the cause.
something about how the limb vibrates maybe?
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If mass alone is to blame, wouldn't those Viking bows be absolute nightmares to shoot?
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I think what badger is saying about tiller makes sense. A sraight bow with a round tiller puts all the force in the handle. Having an eliptical tiller or a reflex deflex design disperses it through the limb more.
Like Dell mentioned also the string can affect it also. I think bows with dacron strings seem more shocky.
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One thing you might see a lot of disagreement on even among the veterans is on limb timing. I don't think limb timing has anything to do with the tips stopping at the same time. I think limb timing has to do with how a limb straightens back out. Ideally it would straighten from near the handle and work out to the tips. If the tips hit before the inner limb is straight the timing is off. The tips can easily get ahead of the inner limbs. Keeping the outer limb stiffer with even stiffer tip areas helps to avoid this.
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Hummm....just trying to visualize the tip hitting or ending before the inner limb does... would that be the result of a bad tiller?
DBar
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I think limb timing has to do with how a limb straightens back out. Ideally it would straighten from near the handle and work out to the tips
Good point Steve. So, short of some kind of photographic/scientific analysis, a bow that is damp in the hand may be more efficient, at least when it comes to vibration? Can you comment about the shockiness/vibration qualities of a bow proven for flight shooting?
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I don't think the limb timing theory is the reason either. Nor tip mass.
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OK PatM I'll bite ...... what do you think causes it??
DBar
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I think limb timing has to do with how a limb straightens back out. Ideally it would straighten from near the handle and work out to the tips
Good point Steve. So, short of some kind of photographic/scientific analysis, a bow that is damp in the hand may be more efficient, at least when it comes to vibration? Can you comment about the shockiness/vibration qualities of a bow proven for flight shooting?
Willie we are shooting arrows as light as 150 grains with no handshock at all. The biggest single loss of energy in all types of bows is limb vibration, it can't be avoided 100% but it can be tillered in such a way that it is minimized and in sinc.
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Maybe timing was the wrong word. I dont know if the limbs can reach home at different times or not. I was refering to the tillering between top and bottom limb being identical based on tracing lines as opposed to going by eye. I think if they are off they can be imbalanced and fight eachother after they hit home causing handshock. At the least a slower bow.
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Maybe timing was the wrong word. I dont know if the limbs can reach home at different times or not. I was refering to the tillering between top and bottom limb being identical based on tracing lines as opposed to going by eye. I think if they are off they can be imbalanced and fight eachother after they hit home causing handshock. At the least a slower bow.
Jesse, I would agree with that, I think the limbs need to match also. That could be a major reason for shock in some bows.
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What is "handshock"? Everybody knows it in practise but how it is defined physically? Is it forward (in direction of the arrow) momentum of the bow, which can be felt? See this video:
https://www.youtube.com/watch?v=xGgWZYny9RM
As you can see, the bow is flying forward, in the direction of arrow (if there would be an arrow...). Try this and every bow is flying forward.
Is the root cause momentum of the kinetic energy of bow after arrow has leaved the bow? Momentum is vector quantity and it has direction. A bow has some kinetic energy (bows potential energy minus arrow's kinetic energy minus hysteresis minus other losses), and momentum, which has direction. So, it would be possible to measure the real handshock with some kind of force sensor, which is put in front of the bow.
Regarding Steve's experience that more elliptical bow has less handshock is valid, because there is less mass (of the bow) which is moving forward. Very elliptical tillered bow has only tiny tips, which are moving forward -> less forward moving mass, i.e. momentum to direction of the arrow.
Note, that tiller difference or limb imbalance has quite minor effect - the bow is staying upright, neither of the limbs are not leaning forward or backward. The bow is flying straight forward.
Easy way to see objectively, how much a certain bow has handshock: Shoot it with open grip and see how far the bow flies... >:D
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Easy way to see objectively, how much a certain bow has handshock: Shoot it with open grip and see how far the bow flies... >:D
(-S
A good explanation of handshock is in the book of Stim Willcox "Art of .....".
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Vibration or kick in the handle upon release is unpleasant.I'm sure as stated by others on here of the different reasons.The lightest arrows I shoot are usually no less than 8gpp arrows and if I don't feel anything it's good to me but normally I usually always shoot at least 10 gpp arrows.
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Limb timing and tiller are important contributing factors to me. Timing and tiller are not the same.
Also, limb mass. Too much mass for the design will add shock.
Yes, indeed, a bow that bends TOO much in the handle will shock.
Jawge
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Limb timing and tiller are important contributing factors to me. Timing and tiller are not the same.
Also, limb mass. Too much mass for the design will add shock.
Yes, indeed, a bow that bends TOO much in the handle will shock.
Jawge
You said timing and tiller are not the same. I agree with that but what is your description of timing? I see it as simply an imballance from top to bottom limb where they fight eachother and rob energy from where it should be going. Imbalance puts energy back in the bow instead of the arrow.
Thats just how i visualize it. I could be wrong. That said on the type of bow i make which is mostly r/d longbow shot 3 under. I make the top and bottom exactly the same with no bend in the handle and shock is not an issue. If they are off a bit the chronograph shows it as well.
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You would have to be a pretty poor bowyer to tiller a bow out with bad limb timing but I'm sure it can be done. Limb timing and tiller are related but there are other factors you would have to screw up to affect limb timing.
Some people describe limb timing as a bow with limbs that come back to rest at different times. For that to happen the bow you would have to have limb tips with vastly differing mass and a cockeyed tiller
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You would have to be a pretty poor bowyer to tiller a bow out with bad limb timing but I'm sure it can be done. Limb timing and tiller are related but there are other factors you would have to screw up to affect limb timing.
Some people describe limb timing as a bow with limbs that come back to rest at different times. For that to happen the bow you would have to have limb tips with vastly differing mass and a cockeyed tiller
subtle diferences do affect the performance though. I dont know how to post pictures anymore now that photobucket doesnt work. I have pictures where you can not see anything wrong with the tiller by eye but when traced at brace the limbs have slight differences. After correction the performance goes up as confirmed by the chronograph. Its Such an easy way to fine tune the tiller because the lines show exactly where the limbs are different. You can fine tune it to the point that when traced with a mechanical pencil you will only see one thin line.
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If you have one limb that is narrow and thick and one that is wide and thin but the draw weight and mass are equal could it be "balanced"?
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If you have one limb that is narrow and thick and one that is wide and thin but the draw weight and mass are equal could it be "balanced"?
i would think so . I have made mostly tri lam type bows where its easy to keep everything matching perfectly.
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This is why I love this forum so much. In the past, I have only had TBB 1-4 as a guide. They're an incredible foundation to learn from, but the opportunity to just ask a question and receive so many insightful answers from so many competent bowyers is an absolute revelation. I don't have a problem with handshock in my bows however I have noticed differing degrees of it from none at all to a certain feeling of it and I wanted to learn as much as I could so as to minimize it as much as possible. I will continue to post questions/queries and remain in utter appreciation to everyone for the answers and feedback. Thanx everybody. Dave
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I have pictures where you can not see anything wrong with the tiller by eye but when traced at brace the limbs have slight differences. After correction the performance goes up as confirmed by the chronograph.
interesting. just to clarify. Are you observing tiller at full draw? on the tree or in a pic?
And when the chronograph shows an improvement, can you notice a difference in handshock?
thanks
willie
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It has been my experience with handshock that very often the most perfect looking tillers are the worst offenders. Unless you know what you are looking for.
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Jesse,
timing to me is when both limbs return at the same time but not necessarily together depends on the wood's character of lack of it.
Good tiller is when each part of the limb is doing its share of the work but yet working harmoniously with the other limb.
There are times (character bows) when the tiller may appear off but, nevertheless, the tiller is right for that particular bow...different limb entry points in the handle, one limb reflexed or deflexed, the presence of knotted areas which should not bend much in relation to the rest of the limb,etc....Here well timed limbs may not end up in the same place relatively but that is ok.
Let's take the situation where one limb is reflexed and the other is not. The reflexed limb needs to bend just as much as the one that is not reflexed. It will stop higher than the other...timing good...tiller good but appears off.
With flawless staves, a good tiller means the limbs will be timed properly.
Tired now. Not sure I am getting my points across.
Thoughts?
Jawge
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I make most of my bows with 1" difference in length between the top and bottom limbs. All my bows are bendy handle HHB bows with an elliptical tiller and most are around 67" length n/n. Even though I have relative thin handle sections (both in width and thickness) I have few problems with hand shock and if I feel a bit of it during tillering, I thin out the limbs a bit more and it goes away. I am however using relatively beefy string silencers that are between 2.5" and 3" long from grey fox and lynx that have relatively long fur.
Now to the Questions: Other than having an elliptical tiller, do the string silencers affect hand shock and to what extent do they affect speed? Also does your shooting style impact it? I shoot mediterranean style and hold the handle comanche style with the thumb upright on the belly.
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Watch this - it seems that limbs are working in unison, right? Are the limbs timed well or not. Tiller is way off but has it really any kind of meaning?
https://www.youtube.com/watch?v=6iHEiBa7zMg
There is a bit handshock (see my fingers) but nothing special. Every bow has that kind of forward motion. Look this video - a lot of handshock because of no arrow:
https://www.youtube.com/watch?v=od8e1MqS_w8
Here is the last example (and my first slow motion video...) - bendy handle bow with shorter lower limb. Seems that limbs are workin in unison but right after brace height, they are NOT vibrating in unison. What really is happening there? Is the reason different limb masses?
https://www.youtube.com/watch?v=T9EUraxn82M
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Hand shock comes from lots of things. B50 is a Hugh cause. Believe me I argued with Rick Barby for a year about this. Two much extra mass around knots and crooked limbs and such. To much mass on the tips!!! Flipped tips that don't bend especially when real wide. Little or no handle. Yes heavy arrows help cover up hand shock but now you have made a slow bow slower. When talking about hunting speed is not everything for sure. A well placed slow heavy arrow will get it done. Heaven bows have more shock just cause . From my experience the two big contributors are b-50 and too much mass on the outer limbs! Arvin
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I have pictures where you can not see anything wrong with the tiller by eye but when traced at brace the limbs have slight differences. After correction the performance goes up as confirmed by the chronograph.
interesting. just to clarify. Are you observing tiller at full draw? on the tree or in a pic?
And when the chronograph shows an improvement, can you notice a difference in handshock?
thanks
willie
I tiller on the tree but then when it looks right by eye i go to the bench . At full brace height I lay the bow on its side on top of paper so i dont mark up the bench. Then i mark an index at the start of the fade and another at the string groove on one limb. I then trace the limb profile onto the paper between the marks. Next i switch to the other limb and line up the two points on the bow to the previous index marks and then trace the limb. If its off there will be 2 lines instead of one. The part where the lines are furthest appart is what needs work. I sand then exercise on the tree and re check. As far as this improving speed yes. As for shock its a bit harder to say because the bows i make do not have a problem with this generaly. the more i think about this i think its probably a combination of things that add up in the bows that are really bad.
Thanks Jawge great explanation on timing.
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My biggest culprit in the beginning was the fact that I did not tiller from "MY" fulcrum point...Letting the tree depict to me the tiller, once I learned to tiller in the hand the last 3-4" by using a camera or a mirror and especially the feel in my own hand 90% of the vibration, noise, bow kick stopped...
The interesting thing is when it feels and looks good in the hand it can look like crap on the tree when final weight and tiller is achieved...
I have seen so many beautiful bends on tiller tree pictures and then the final draw in hand is so different...
You see so many variables in shooting stiles...Heel down, high grip or whatever...My fulcrum point gives me my final tiller and balanced limb timing...It's very easy to see, take pictures of your bow drawn heel down, mid handle and a high grip and compare the change in the photo's...A tiller tree is NOT a human being...
Just my 2 $ , Don
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That's a good point to bring up. If your shooting fulcrum point is not the center of the bow or the deepest part of your grip like on the tree it will be an issue.
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Jesse,
Once you have learned your fulcrum point you can incorporate it to your tree and pull from a predetermined nocking point and come dam close...But I still do the final adjustment based on feel and pics...I shoot 3 under and have a piece of leather that resembles my fingers under my nocking point that I pull with...If you look carefully you will see the "projected" nocking point attached and marked, the 3 under leather strap I use as my fingers...This is a character stave and has a wiggle at the bottom limb so it appears stiff in the pic near the string...I also think Nocking points should be taken into consideration when tillering, hardly ever talked about...Fulcrum and Nocking points work together and I try to incorporate both simultaneously in my build....
This is by far from perfect, just an example and my 2 cents...Hoping to help someone with an idea...
Don
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Don, do you clamp your bow to the tree? Any time I try and do the fulcrum and nocking point thing the bow sits at an angle. Way different than what your picture shows.
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DC,
No, but probably should, here is an open pic of my tree with a rounded base for the handle...Usually if I'm close at floor, the pressure will balance...If not, I go back and adjust my brace and try again...If you notice the first set of pics, there is what I call a guard board to keep from slipping off the tree towards me...This set up brings me really close to balanced in the hand...If my bow starts slipp'n I am way out of balance...
Don
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Nice set up Butch. I use a flexible strap on my ELBs mostly now, it allows them to tilt if they are out of balance without sliding off.
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I have a friend, Richard..."half eye" that doesn't even own a tiller tree or stick...He does all his from floor, then to his knee, then in hand which I think is astonishing and about as real as it gets...I proudly own 4 of his bows and even these shorty's are dead in the hand no vibration...No tree depicts his tiller or balance...
Rich, hope you don't mind me using these pictures Sir...
Don
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Here is one more example of fulcrum placement...This was a bend experiment with OS...My fulcrum on the bow is almost 2" below center, see hand placement...I was trying to get the arrow slightly above center of both limbs...I was using split finger because I was building this bow for "half eye"...
Nothing is perfect here, but I want you to see the "differences in bend" from hand to tree as I was weighing the bow...Looks crazy...vibration, hand shock was low on this build for my form...Rich would have to give the final report...
Sorry to keep rambling here, Don
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Wow! There's some talent on this site.
I think tillering from where you will grip the string is just fine.
I just could never get used to it.
I tiller form the center and then finish it in the hand by using a large mirror, in front of a window at night or digi tillering.
Also, I once tillered a bow made with stone tools by using shadows.
Jawge
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I shape the handle before tillering. My tree has a rounded profile that fits the grip at the fulcrum point. This one is stiff top limb yet in the picture. Just trying to show the tree setup