Primitive Archer
Main Discussion Area => Bows => Topic started by: Badger on March 20, 2008, 02:59:21 pm
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I have seen the topic of handshock come up every now and then. I have never really seen a perfect answer as to why some bows have handshock and some don''t. Some bows look like they would be shocky and are not while other bows look like they would not be shocky and are very shocky. Last weekend I shot a bunch of different bows, every one I could get my hands on. The majority had more shock than I like but tolerable while others were miserable to shoot. I spent several hours just watching the bows being shot to see if I could pin point anything worth looking into. You could actually see with the naked eye the center of the limbs bulging forward and vibrating after the shot. Some bows had a slow reverberating heavy type shock while other bows had a sharp quick painful jolt. A couple of the bows were very narrow low mass bows but still had painful handshock. Pyramid bows in general seemed to have less shock. Most all of the r/d bow designs with stiff outer tips were almost shock free. Even some of the bendy handled longbows were shock free. The most obvoius predictable shockers were overbuilt bows with long paralell limbs tapering the last several inches to the tips.
I still haven't come up with a good answer that covers it but it sure does look to me like limb timing is the biggest culprit right along with unevenly stressed limbs. I took one of my bows that had a sharp painful jolt to it and just narrowed it a bit midlimb, took about 3# off it and got it bending a little more in that area and the shock just disappeared, Anyone else have thoughts on handshock? Steve
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narrower tips help. string silencers reduce vibration also.
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my two bows have very little to no handshock
one is 70" ntn and 1 1/2 at midlimb with the last 15" inches tapering to 3/8 at the tips
the other is 66" and 2" at midlimb with the last 15" tapering to 3/8 at the tips
both these bows are a pleasure to shoot i love them
that gets me thinking i still havent posted pictures of that second bow
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Although I typically try to have the last 4-6" to the tips nonbending, I try and keep the mass weight as low as possible in the tips.
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Hmmmm....could you explain what you mean by "limb timing"?
As for unevenly stressed limbs adding to handshock...I don't know about that one. For example, it's been observed that "whip tillering" helps to reduce hand shock....and so does a stiff handle.
I've been shooting like crazy lately to discover what causes hand shock in short bows. It seems to me that there are two "stages" of hand shock....the 1st stage is at the moment of release and the 2nd stage is when the string snaps tight after the arrow leaves the bow. The 1st stage messes with your accuracy and the 2nd stage messes with your pain tolerance. ;D
My bows made of high stiffness wood (like HHB) have 1st stage hand shock and my bows made with low stiffness wood (like Juniper) have 2nd stage hand shock. My bows made of ipe seem to have BOTH stages of hand shock. :-\
Overall, a loose grip eliminates hand shock.....which leads me to believe that whatever causes the handle to vibrate is the culprit. Lighter tips and a heavier grip seem to be the logical cure.
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Good point Jack, I think there are actually several culprits. A lot of folks feel harmonics plays into it and it does make sense. The one little bow I had the problem with you really couldnt even feel the shock, just the pain as it was very sharp when it hit, I really don't get many bows that are shocky but I have had a few doosies that always puzzled me. Steve
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Center section mass vs. tip mass. If the center is too light than the mass and energy of the limbs will move the center. Mainly seems to come from the limbs moving more and more forward of the center, hecne either narrow tips or high brace heights.
They had it in an old magazine article on why some longbows (fiberglass laminated) were so much less reliable than modern recurves.
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I agree also that's there's several causes of handshock Steve. Biggest one for me is hand placement and timing. Take for instance you grip a bow designed for a low wrist and then shoot it using a high wrist, or vice verse. Limb mass is now out of sync and you'll experience handshock. Proper grip for proper design is required. But even that isn't enough for proper timing if dimensional center and static balance is out. They should be one and the same.-ART B
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I have found that reflexing the tip and keeping the last 4-6 inches non- bending eliminates most of the hand shock. On extremely snakey bows I do the final tillering by feel rather then sight. It's kind of hard to explain, but on these bows I can usually determine where the shock is coming from when I shoot them. Although I don’t use the harmonic theory when tillering, I have found that the bows with the least amount of hand shock have the limbs bending evenly throughout the draw. i.e... Both tips when drawn are at the 10”, 12”, 20”, ECT, at the same time throughout the entire draw.
Walt Francis
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I agree with Walt.
Evenly bending limbs are a recipt against handshock.
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There are other more obvious causes like a bow that bends too much in the handle and nocks that are too heavy. Timing is the one that is the least understood. Limb timing is very important. I can watch the limbs flex and return on my rope and pulley. That will give me somewhat of indication. Later when I go out to shoot the new bow. I pay attention to handle pressure to make sure it is even as I draw and release the arrow. Limb timing and tiller are related but they are not the same. A bow can appear out of tiller, still have good timing and shoot well. Tillering character bows makes a bowyer really aware of timing . Anyway, that's it for now. Here is an example of tiller and timing. Jawge
http://mysite.verizon.net/georgeandjoni/seneca.html
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I've only shot my own bows and truth be told I've never noticed hand shock. When I get to Pappy's I'm
hoping to get a chance to shoot lots of other folks bows for comparison sake. So if any of are going to TOJAM
and ya have a real teeth rattler please bring it, I need to experience it first hand. One thought I have on hand shock is
even when I was shooting compounds I noticed so many people gripping the handle like they were choking a rat
and I believe this also contributes to hand shock. I was taught loose grip not death grip.
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I notice handshock when I'm shooting light arrows. I have some Goldtip Traditional carbons, and when I shoot them out of most of my bows over 45#, recoil becomes an issue. With the same bow, and hunting weight arrows, handshock is gone.
I agree, a well tillered bow, with limbs working equally and properly timed, will have less recoil. I also notice more handshock with shorter bows. There is nothing more smooth than a 72-76" ELB. It also seems to me that bows with excessive recoil are noisy.
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My own pet theory is that a bow without handshock has limbs that straighten out near the handle before they straighten out at midlimb/tips. When such a bow slams home, there will be less mass in motion for the string to stop.
On the other hand, a bow that has much handshock, will have limbs that first straighten out at the tips/midlimb. - which means that almost all of the limbs mass will be in motion just before they gets stopped by the string.
Therefore, I think one should stress the limbs progressively more from the grip to the tips, if one should want to make a bow with little hanshock. If the outer parts of the limbs bend more than the inner, it will take the outer parts longer time to unbend than the inner, which means the inner parts of the limbs will stand still when the string stops the bow. Here one should probably also take into consideration that the outer parts of the limbs naturally will unbend later than the inner, because the outer is cast forward as they have to unbend, which means that it is perhaps not fully necessary to stress the outer limbs more than the inner.
Can it be disproven?
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kviljo That would explain why a whip tillered bow would have low shock. I have an old fg longbow that looks a little whip tillered and it is still the smoothest shooter i have. To bad its backed with f.G. Jesse
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I think most bows with hand shock is because they aren't as finely tuned as they need to be and much of this comes from experience and sometimes a bit of hands-on coaching.
I can relate Steve, and sometimes it's why I'm checking out what the guys are making to help them reach the next level as opposed to working on bows. I do that enough at home..
If this stuff was easy, it would be boring ;)
Rich
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I don't believe timing has anything to do with handshock. How the bow is tillered makes a big difference. Light tips will make some difference. Handshock happens when the string slams home and the residual energy has no place to go but to travel down the limbs and into the handle, this is especially so in bows that bend mostly in the inner limbs. If a stiff handled bow is tillered to work more of the limbs and just leave the tips stiff then when the string slams home much of that residual energy will go into the limbs by flexing them rather than traveling down the limbs into to the handle. Also the additional mass in the outer limbs don't help either
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Marc described my exact feelings. Arrow weight can have a effect (like Marc said) by NOT obsorbing residual energy from the limbs....but there are limits when it comes to arrow weight. Great description Marc...
Brian
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Timing is crucial. I used to think that bows that bend in the handle result in more hand shock. Brad Smith called me on that and he was correct. Bend in the handle bows are not automatically shock filled. Marc, I agree that tiller and timing are related but a character bow that appears out of tiller is not necessarily so because the limbs flex and return in unison. But I already sad that in a previous post. Here's the link for anyone who is interested. :) Jawge
http://mysite.verizon.net/georgeandjoni/seneca.html
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Steve, I suspect that timing and mass have a lot to do with it.
Kviljo's theory would have to do with timing and mass. I think that if a bow has the mass near the handle return to rest sooner the whip tillered ends would act as shock absorbers because they bend easily. If the the tips return faster then the handle area and your arm are the shock absorbers. In these bows with both limbs hitting brace height at the same time then you would receive from to back vibration.
Some bows could have one limb reach brace height before the other then pass it before the string slams tight. The limbs would have to vibrate back and forth to reach equilibrium at brace height. This would give you hand shock where the top moves forward and back while the bottom is doing the opposite. This is exactly why I have always been scared to make a spliced bow with top and bottom limbs of different wood.
I have some ideas I think I will try today to test these ideas. Justin
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Some interesting replies. When I refer to limb timing I don't actually mean they are not returning to brace at the same time because I believe they have to as they are attached by the same string. I have seen smooth bendy handle bows and shocky ones as jawge pointed out, I have also seen whippy ended bows that have shock. Too much mass in the last several inches I agree is a common culprit. I am leaning toward a primary cause being tiller shape not agreeing with the front view shape of the bows, for instance a pyramid bow will have approx equal thickness and a circular bend, they almost never have bad handshock, recurvesm and dr bow will usually have paralell limbs with stiff outer limbs, they very seldom have any real handshock, well made elb style bows with even tapers both in width and depth will seldon have handshock to speak of. Bows that have long paralell limbs but still remain relatively stiff in the outer limbs or even circular circular in tiller will often be the worst offenders. I think if a limb is paralell it should progressively bend more into the paralell until the limb starts to taper and at that point start to stiffen up a bit. (elyptical). I think if there is anything on the bow that doesn't seem to make sense or logic it will cause shock to one degree or another. Steve
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For grins and giggles put a bow that has excessive hand shock on a tiller tree, preferably a bow that seemingly has no obvious reason for same, pull it to full draw, let it down and see if the bow rocks in the cradle which would be indicative of poor timing. Gotta go. Jawge
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Thats a good point jawge, could maybe move the nock position around a bit also as Art suggested and see what happens. Steve
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I agree with George. Bendy handle bows are not necessarily shocky. I have a beautiful Bickerstaffe longbow, bendy handle, full compass tiller, 74" NTN, with horn nocks. It's absolutely expertly tillered, and it's the most quiet and smooth bow I've ever shot... NO hand shock. I use fairly heavy wood arrows. In speaking with Pip this past summer, he mentioned the importance of proper timing in the limbs, keeping the tips as light as possible, and the value in using non-stretch string material like FF, which he supplies on all his bows.
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I've thought about the physics involved. I hate doing this even though I love science. I spent my adult life teaching youngsters about science and trying to transmit my love for it to their lives. I mean I was out in 15 degree F temps watching the last lunar eclipse. For some reason I've chosen to limit my involvement in the science of archery. But here goes, I had some help with this but I forget who it was on here, I do believe that in properly timed bows the force vectors result in a forward movement propelling the arrow forward allowing for the most efficient energy transfer. Imagine 2 billiard balls going at the same speed each say at a 45 degree angle to each other and impacting another billiard ball. If everything is timed properly that billiard ball will go forward. Imagine those first 2 balls to be the bow's limbs. If they are synced all is well. If they are not one will hit before the other and cause erratic motion in the third ball. Same with an untimed bow. The energy is transferred to the arrow but perhaps at different times. The shock is felt by the archer. That's it. I hope I wasn't too unclear. The concept of vectors is tough to get across. As an aside the best and brightest 2nd year chem students had difficulty thinking of vectors in regard to molecular shape. Ok that's enough science. I'm retired. Jawge
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As Art mentioned varying where the arrow is shot even by small degrees may mitigate handshock. The archer will also have to change the nock point. My last hickory bow was pretty shocky when I first shot it. All is well now. I flipped the bow around and shot it the other way. The limbs must have been untimed in the first instance. Flipping it around timed them nicely. Go figure. Sometimes it's hard to see limb timing on the tiller tree. Ok. I'm done. :) Jawge
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Great analogy George.
Steve, you are right in that the string will become tight on both limbs at the same time. However one may have reached brace height faster than the other and gone beyond. The string would get tight before the second reached brace height. Both limbs will eventually settle at brace height, but they will oscillate to get there. Think of an overbuilt 60# limb on top and a super efficient limb on the bottom. The speeds will vary for these two limbs much like it would for two different bows. Like George said though, this could be corrected by raising or lowering the nocking point. I guess it will be easy to test this theory, take a sweet shooting bow and shoot it with the arrow 1/2" lower then 1/2" higher and see if it has different hand shock from what it did originally. Justin
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Thanks, Justin. Good idea about varying the nock point. Jawge
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For grins and giggles put a bow that has excessive hand shock on a tiller tree, preferably a bow that seemingly has no obvious reason for same, pull it to full draw, let it down and see if the bow rocks in the cradle which would be indicative of poor timing. Gotta go. Jawge
George
That's not poor timing. That's just a bow that has one limb too strong for the other(out of tiller). I have said this before and Steve said it above. A bows limbs have to return in unison because they are pulled back that way.
If one limb is much stronger than the other then I would have to agree that it could deliver more handshock but not necessarily so. If the stronger limb is tillered to be stiffer in the outer limb then that would increase handshock.
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I have built a lot of very efficient bows and when shooting those bow have varied the nocking point. If the bow is tillered right then moving the nocking point up or down does not increase handshock.
Now adb3112 mentions above a longbow he has that does not have any handshock. He also says he shoots heavy wood arrows from that bow and most everyone knows that heavy arrows is one way to tame handshock. I've never met a longbow that didn't have handshock, unless shot with heavy arrows.
A good way to tell if your bow has handshock and this is a full proof method is to test that bow with an arrow of 6 or 7 GPP, even better if you use an arrow of less than 6 GPP. I have shot some of my bows with arrows of 5GPP and handshock is negligible with a well tillered and efficient bow
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I think a sure fire way to find out would be to get 2 bows of similar design and weight one with lots of shock and one without and pull them to the same draw by the same person and film it with a super high speed camera. I think it would be clear what was causing the shock. Jesse
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Marc, perhaps we can agree on this. Limb timing as evidenced by a rope and pulley or by shooting the bow and sensing hand pressure on the handle, is another aid to make sure the bow's limbs are in tiller. Tiller off means limbs are not timed. Tiller is not so easy to judge in a character bow. Jawge
http://mysite.verizon.net/georgeandjoni/tillercheck0002.jpg
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George
Perhaps we are thinking of the same thing but using different words to convey our thoughts.
To me if a bow pivots, whether on your rope and pulley or by pulling by hand, it's because one limb is stronger than the other. To me this would make the bow out of tiller. Generally we make bows with 1/8" positive tiller and at that the bow stays steady in the hand when drawn. Increase the positive tiller to 1/4" or even 1/2" and then the bow will pivot. The limbs would still return in unison when shot because both limbs are tied together by the string and when pulled back.
You can move the nocking point up by 2" and the limbs would still come back in unison, they have to because they are tied together and the hand pulls them back in accordance with their requirements. The stronger limb would travel less and be under less strain than the weaker but it would also have more mass, that could increase handshock but still not necessarily so. The weaker limb would be lighter and be under more strain so will come back faster. They both will meet at brace at exactly the same time.
There are external forces that can affect the return, such as if one limbs is much wider than the other and becomes affected by wind resistance.
Tell me I'm wrong :)
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The limbs can have a different tiller, and when checked on the tiller, they will always return at the same time. But drawing it and letting it down slowly isn't the same as shooting it with an arrow or dryshooting it. If one limb is faster than the other, it will return faster, and go beyond brace height. When that happens, the string slams tight when one limb has gone past braceheight*, and the other has not reached braceheight* yet. Then the limbs have to return to the normal braced position after the string is tight, giving handshock.
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I am not the expert but Kviljo's explanation makes the most sense to me. Jesse
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The limbs can have a different tiller, and when checked on the tiller, they will always return at the same time. But drawing it and letting it down slowly isn't the same as shooting it with an arrow or dryshooting it. If one limb is faster than the other, it will return faster, and go beyond brace height. When that happens, the string slams tight when one limb has gone past braceheight*, and the other has not reached braceheight* yet. Then the limbs have to return to the normal braced position after the string is tight, giving handshock.
The one that returns faster will be the limb that is stressed more and that will be the weaker limb but it also has to travel farther because it is bent further. I'm sorry but I still stand by my explanation as the most logical one, until somebody has one that shoots mine down.
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I was tillering a bow yesterday. It was a new bow that was tillered, shooting sweet and the top limb relaxed a little and the bow got out of tiller. Hand shock went from "0" to toe nail jarring. As I scraped a little of the bottom limb, shooting a couple dozen arrows between scraping the hand shock diminished. When I had the limbs back in time the hand shock was mostly gone. It is limb timing for me that determines most of the hand shock with overbuilt limb mass being second.
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Mark, I tend to agree with yours, I honestly have struggled with this for several years. I can look at a bow now and almost tell for sure if it will have handshock or not but not really sure what I am looking at. I know that makes no sense. I think Eric brings up some good points as well. An overbuilt bow can be deceiving as well. I recently built about 1/2 dozen boo backed osage bows, most of them are near 1 1/2" and slightly less at the fades. The most overbuilt one of them is less than 1" wide near the fades and by far has the lowest mass but because of it's tiller shape it was slightly overbuilt and had the worst handshock. I slightly narrowed the just past mid limb section changing the tiller shape and the handshock was gone. I think most of the handshock takes place because of the near midlimb section of wood not bending according to it's width in relation to the rest of the bow. Steve
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The limbs can have a different tiller, and when checked on the tiller, they will always return at the same time. But drawing it and letting it down slowly isn't the same as shooting it with an arrow or dryshooting it. If one limb is faster than the other, it will return faster, and go beyond brace height. When that happens, the string slams tight when one limb has gone past braceheight*, and the other has not reached braceheight* yet. Then the limbs have to return to the normal braced position after the string is tight, giving handshock.
The one that returns faster will be the limb that is stressed more and that will be the weaker limb but it also has to travel farther because it is bent further. I'm sorry but I still stand by my explanation as the most logical one, until somebody has one that shoots mine down.
My thought goes right along with Steve's mass calculator. If one limb is wider and thinner it can bend the exact same distance as the other that is narrower but thicker. The first limb will have more mass and return slower to the original brace even though it is the same poundage of limb. It is still a 60# limb but is inefficient because it wasn't built to the best dimensions for the wood. If it is possible to conceive 2 bows that shoot 150 fps and 180 fps with the same length, draw weight and arrow weight, why not conceivable to have two like limbs with some variance? Justin
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I haven't had time to respond to your post Marc but I will asap. been at church Gotta go now too. Jawge
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The limbs can have a different tiller, and when checked on the tiller, they will always return at the same time. But drawing it and letting it down slowly isn't the same as shooting it with an arrow or dryshooting it. If one limb is faster than the other, it will return faster, and go beyond brace height. When that happens, the string slams tight when one limb has gone past braceheight*, and the other has not reached braceheight* yet. Then the limbs have to return to the normal braced position after the string is tight, giving handshock.
The one that returns faster will be the limb that is stressed more and that will be the weaker limb but it also has to travel farther because it is bent further. I'm sorry but I still stand by my explanation as the most logical one, until somebody has one that shoots mine down.
Just to be sure that I understand your argument: you are saying that the limbs of a bow, when shot, will regardless of tiller and mass placement return to the same position as the braced, without one limb going past braced position?
I think that one could be shot down quite easily with a badly made bow filmed by a high speed camera :)
Shooting it down with words will be a bit more difficult. But I don't think it is correct that the faster limb will be the one that is stressed the most. Imagine an extreme case, where you have a bow with two identical limbs. Both are equally fast, untill you add some dead weight wood to the tip of one the limbs. Now they won't be equally fast, and you could even stress the limb with the dead weight more without making it faster. The one with the dead weight will travel a lot slower, and the string will slam tight before the slow limb has returned to it's (non-motion) braced position.
This could be tested quiite easily, just taping a small weight to the tip of one limb on a bow that has no handshock. It should gain handshock. And the other way around, one should be able to take a bow with handshock, and remove the handshock by adding weights to one limb. - that is, if the handshock was due to timing between the limbs in the first place, and not due to the tiller of the bow.
Interesting discussion!
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What Kviljo said ;D! That's a why when you lose your positive tiller your arrow's trajectory drops. Here the top limb is stronger and gets home first throwing the path of the arrow downward. Not only do I set my positive tiller while shooting the bow in but I can also adjust my arrow's impact with said tiller. -ART B
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I almost hate to keep weighing in on this but I am trying to learn. It seems to me that when you are drawing back pulling on the string the limbs have to move at the same timing because they are being pulled by the string but when you release all bets are off because now the bow limbs are pulling the string and if they are going different speeds I could see that being a problem. An exact weight on one tip should demonstrate this as was said. I think some experimenting is due ;D Jesse
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Mark, I tend to agree with yours, I honestly have struggled with this for several years. I can look at a bow now and almost tell for sure if it will have handshock or not but not really sure what I am looking at. I know that makes no sense. I think Eric brings up some good points as well. An overbuilt bow can be deceiving as well. I recently built about 1/2 dozen boo backed osage bows, most of them are near 1 1/2" and slightly less at the fades. The most overbuilt one of them is less than 1" wide near the fades and by far has the lowest mass but because of it's tiller shape it was slightly overbuilt and had the worst handshock. I slightly narrowed the just past mid limb section changing the tiller shape and the handshock was gone. I think most of the handshock takes place because of the near midlimb section of wood not bending according to it's width in relation to the rest of the bow. Steve
Exactly what I mean Steve. By changing the tiller to have the wood work more mid limb you reduced handshock.
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I think that one could be shot down quite easily with a badly made bow filmed by a high speed camera :)
Shooting it down with words will be a bit more difficult. But I don't think it is correct that the faster limb will be the one that is stressed the most. Imagine an extreme case, where you have a bow with two identical limbs. Both are equally fast, untill you add some dead weight wood to the tip of one the limbs. Now they won't be equally fast, and you could even stress the limb with the dead weight more without making it faster. The one with the dead weight will travel a lot slower, and the string will slam tight before the slow limb has returned to it's (non-motion) braced position.
This could be tested quiite easily, just taping a small weight to the tip of one limb on a bow that has no handshock. It should gain handshock. And the other way around, one should be able to take a bow with handshock, and remove the handshock by adding weights to one limb. - that is, if the handshock was due to timing between the limbs in the first place, and not due to the tiller of the bow.
Interesting discussion!
You are assuming here that a high speed camera would shoot my argument down. An assumption and facts are 2 different things
Adding weight to the tips would slow the limb down but what does that have to do with this? All you are describing here is one limb that has too much mass and another that is well built. I do see your point though. You would have to have a bow that looks extremely odd to have the statistics that you are talking about but you never know. There may be bowyers out there that are unable to see the difference.
By your arguments a bow with unequal length limbs would have tremendous handshock.
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What Kviljo said ;D! That's a why when you lose your positive tiller your arrow's trajectory drops. Here the top limb is stronger and gets home first throwing the path of the arrow downward. Not only do I set my positive tiller while shooting the bow in but I can also adjust my arrow's impact with said tiller. -ART B
No offence Art but I try to see in my mind what you describe and the way I see it if the top limbs hits first the arrow should go up not down
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Holy wuh eh! All this is fascinating but my method is if it shoots and can make meat its a bow 8)
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Yeah, I'm probably wrong about that one Marc ;)!-ART B
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Marc, let's see here.
"Perhaps we are thinking of the same thing but using different words to convey our thoughts. "
Perhaps but I don't think so.
"To me if a bow pivots, whether on your rope and pulley or by pulling by hand, it's because one limb is stronger than the other. To me this would make the bow out of tiller. Generally we make bows with 1/8" positive tiller and at that the bow stays steady in the hand when drawn. Increase the positive tiller to 1/4" or even 1/2" and then the bow will pivot. The limbs would still return in unison when shot because both limbs are tied together by the string and when pulled back. "
If the limbs pivot then one is returning home before the other. Has to be or it wouldn't pivot. Agreed- out of tiller limbs will not be properly timed.
"You can move the nocking point up by 2" and the limbs would still come back in unison, they have to because they are tied together and the hand pulls them back in accordance with their requirements."
I don't think so.
"The stronger limb would travel less and be under less strain than the weaker but it would also have more mass, that could increase handshock but still not necessarily so. The weaker limb would be lighter and be under more strain so will come back faster. They both will meet at brace at exactly the same time."
I say the stronger limb would be under more strain. It may not have more mass. For example it may be reflexed and the weaker one deflexed. They may have the same mass. If the bow rocks they will not meet at the same time.
"There are external forces that can affect the return, such as if one limbs is much wider than the other and becomes affected by wind resistance."
No-inconsequential.
"Tell me I'm wrong "
I would not be so presumptuous. :)
Jawge
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George, if a bow pivots in the hand, the limbs will reach the braced position at the same time if you let the bow down slowly. The reason it pivots is because one limb travels longer. But they will still reach the braced position at the same time, as the limbs are tied together by one string, as Marc sais.
But the same limbs may not reach the braced position at the same time when you shoot the bow. One limb may be faster than the other. Agree?
Marc, it wasn't totally an assumption, because I do believe I can see it happening as I described in the slow motion shot in the UK defence academy longbow tests video. - I am of course by no means saying that the bow used is badly made, but it does look like it has some handshock.
I'm not sure how much handshock a little overbuiltness in one limb would add, but it could be tested. If it takes a large amount of excessive wood on one limb to give the bow handshock, this might not be the reason for handshock.
But I don't think a bow with unequal limb length automatically will have handshock, because the limbs can be made to return to the braced position at the same time regardless of one limb being one or two inches longer than the other. However, even if such a bow had the limbs returning to the braced position at the same time, the heavier limb would want to travel forward more than the shorter lighter limb, so it would probably gain some handshock there too. - yet another way of gaining handshock.
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"If the limbs pivot then one is returning home before the other. Has to be or it wouldn't pivot. Agreed- out of tiller limbs will not be properly timed."
If you say so George
""You can move the nocking point up by 2" and the limbs would still come back in unison, they have to because they are tied together and the hand pulls them back in accordance with their requirements."
""I don't think so.""
I believe Tim Baker did this very test at Paleoplanet last year and according to him the bow shot well.
kviljo
I wonder how much handshock a Japanese Yumi bow has
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I just want to say that I know Marc and Jawge are getting old because they have this same discussion every couple of years ;)
Nobody has budged an inch or even come close to changing their mind.
I will just chime in and say that bows that have terribly unequal limbs can shoot sweetly(Yumi, Hun, and Tim's 8 foot section of cane)
A tiller tree and a hand and fingers have little in common.
Of course I've said all this before (and I remember saying it too). ;D
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Something I have noticed here is that all the guys discussing this topic here are pretty well rounded bowyers. This tells me that handshock issue is more complicated than some of us think it is, Actually pretty easy for most of us to build a bow that doesnt have shock, but identifing where it comes from seems to be a bigger issue. Steve
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This tells me that handshock issue is more complicated than some of us think it is, Actually pretty easy for most of us to build a bow that doesnt have shock, but identifing where it comes from seems to be a bigger issue. Steve
Boy I will second that.
I got some stick on lead weights in 1 oz sizes. I am going to play with them and see what happens. Justin
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no 2 trees are alike.
no 2 staves will react the same cut from the same tree.
only the BOWYER can help a piece of wood along to become a "sweet" shooter.
for those who push their limits with designs,are pushing there limits on shootability.
one bowyer can make 2 bows from sister staves and one will be "better" in different ways than the other.
wood is not a consistant medium for comparison!!!!bottom line, wood is not a common medium for such intrusive study,as cells break down,different moistures,working enviroments...etc.
so why keep chasing tails in circles to produce the so called "super bow"?
one thing that makes good bow BETTER is CONSISTANCY in tecnique.if something works dont try to fix it.
if you "think" it could be better, make another bow its only wood...BUT AS I SAID BEFORE,AS WOOD IS A TRICKY MEDIUM AND IS NOT THE SAME WOOD EVERY TIME....YOUR BOW MAY AND PROBABLY WILL SHOOT DIFFERENTLY EVERY TIME YOU MAKE A SO CALLED "IMPROVEMENT!"
would you rather see many of your bows working and in the hands of your friends in the hunting woods and fields, or would you like to have alot of firewood glowing from your fireplace gathered from all the bows youve tried to make but broke and along with the hard work and trial and error, hard earned at that, shining light on the one superstar that made it ...hanging on the mantle?
all this time reading about hand shock and writing this post i could have debarked a stave and got it ready to shave wood!
mbg
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Mpg, handshock is a very important issue with bows, very seldom will you see a high performance bow that has any handshock. The everyday shooters we make are the culprits. For some reason you have a problem with all my threads, you say if something is working why change it? If a bow has handshock it is not working like it is supposed to work and needs fixing, the remedy is not difficult, understanding what causes handshock can help remedy this common problem that makes so many bowyers not enjoy shooting their bows. I have made it a point to not comment on your threads unless I have something positive to say, however you can feel free to post anything you like on my threads as it should be. Steve
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badger,
this is an open forum.
i think that what i say is important and i have no problems with your other threads as well.
i like the IDEA of a primitive website.
and for some reason all of the things i see latley, not only from you but others as well....has just gone off track with some of the traditions and ideals of primitive technology.
the only thing i had a problem with an earlier post with you was that it was and is hard for me to choke down the words primitive and mass calculator in the same breath.
there are not to many websites with such active public forums outthere talking about the primitive skills we have learned and are putting to use now,and try to pass along in a positive manner.
i am willing to bet that you are an intelligent man,and have put lots of thought and theory in your work and studys on bowmaking.
myself i am fairly new to the sport and bowmaking but quickly learning that newer and more "updated" ways are pushing us further and further away from REAL primitive skills.
i may make a bow with slo cast and uneven tiller and heck not even a matched arrow in my quiver....but in the 1/2 hour or less it takes me to make such a weapon, i could use the rest of my time killing something with it.
primitive archery was about REASON.not theory.
you make a bow to feed your family, not to outshoot your neighbor.
english longbowmen had standards as they pumped out bows to the masses and they knew if they fine tuned them it could be quite better.....BUT for the time bieng they knew if they stuck with the BASICS they would build a functionable weapon.
how trad. is the trad gang?
it is by far growing by leaps and bounds.
we have a growing site here that i would hate to loose to bowyers making bows with more dial indicators and calculators etc. than with drawknives and or stone .
where do we make the cut off point to primitive?????
i am worried,i am defensive.
not just to you.
the more the communities keep splitting up and deversifying the less numbers we have in a whole believing in the same wants and needs , of keeping the dimly lit lights of our primitive roots glowing.
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That was a good post MPG, I honestly did appreciate your honesty and had a feeling thats what you were feeling with this whole thing. I can't speak for anyone else here but I do know for a fact that many of us and proably the majority of us here hold in the very highest regard those that make the most primitive of weapons in the most primitive ways. These sights will attract all of us that make bows from natural materials simply because there is no single aspect of this sport that is big enough to support a smaller group that specializes in any one particular type of bow. If you saw the bows I shoot when I go shooting you would shake your head, I shoot what looks like bent sticks, I seldom even wrap a handle, I use whatever staves I can get my hands on, usually elm, maple or osage which I happen to favor these three, but I grab and whittle anything that looks like it might have a bow in it. Flight shooting is simply a hobby of mine that requires I try to build a bow that is fast. If you could stay open minded to the idea of working with mass you might see where that is comming form. Years ago groups of people would usually be working with only one or two kinds of trees and using the same style bows. They would become very intamate with the demensions needed to make a serviceable weapon and just proceed with that. here we change and experiment with different styles and different woods, we lack the generations of bow builders before us to pass down the best styles and demensions. It might take us years worth of work and thousands of dollars spent on wood just to become proficient with a few basic designs. The mass calculator is not scientific and was derived entirely from building and weighing bows and then just taking notes and making comparisons. It makes no claims to be exact either, my only claim is that building a bow by weight to match different designs is probably more accurate than trying to select randomly a demension. Myself like many other bowyers tend to become more primitive the longer we do this although we still may play around with pet projects we have going. I have been working on a stone bow now for about 5 years, still havent finished it. I think it is safe to say the we welcome all kinds of natural material bowyers to these sights and we choose from them whatever styles most attract us, Some of us hunt, some shoot target, some flight, some are more artistic, and some just like to whittle and see wood bend. As long as we are enjoying the hobby at whatever level we choose I feel it is a good thing, Thanks again for expressing yourself honestly, thats a good thing also. Steve
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MBG
Wow do you ever have a burr up your behind. Personally I have a bit of a burr up my behind also but it's from people that seem to have this thing about "primitive". Probably this is something that comes from my native heritage and tied to the immigrants that came here thinking the indigenous people were primitive savages that did not have any rights, including the right to own the land ::).
Do you think that sinew backing a bow is "basic" bow building or making horn bows "basic" bow building? Laminated bows were being built by so called "primitive" people. It takes a bowyer many years to fine tune their art down and some never do. Steve's mass calculator can help new and old bowyers make finely tuned bows quickly and easily.
Sure you can keep making your bows as simple as possible. Heck you can even just tie a string on a stick and never mind tillering, now that is really primitive. Hmm sandpaper, chainsaws, and drawknives? These are not "primitive", they'll have to go ;D.
The fact is that the English made bows designed for the optimum considering the availability of the wood and the use of the tool. Their warbows were fantastic weapons that cannot be improved upon even now.
Another fact. If you adopted the attitude of live and let live then you would find yourself to be a lot less worried and a lot less defensive.
As you say. You haven't been at this very long. Give it a few years and maybe you might have a change of mind but even if you don't that's still ok. In the spirit of my ancestors I welcome you but please don't do as the Europeans did and bite the hand that feeds you
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"George, if a bow pivots in the hand, the limbs will reach the braced position at the same time if you let the bow down slowly. The reason it pivots is because one limb travels longer. But they will still reach the braced position at the same time, as the limbs are tied together by one string, as Marc sais.
But the same limbs may not reach the braced position at the same time when you shoot the bow. One limb may be faster than the other. Agree?"
Nope. I can feel pivoting when I shoot it too.:)
Jawge
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Badger, funny you said say this.
" Something I have noticed here is that all the guys discussing this topic here are pretty well rounded bowyers."
One of the other sites I frequent had a thread on old pictures. Damn was I skinny. :)
Jawge the Well Rounded
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Pat said,
"I just want to say that I know Marc and Jawge are getting old because they have this same discussion every couple of years."
Marc is not getting old. :)
Jawge
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"Personally I have a bit of a burr up my behind also but it's from people that seem to have this thing about "primitive". "
Speaking of burs up behinds - just a reminder that anyone over 50 should be thinking about getting a colonoscopy. Nu'in to it. I love you guys. Take care of yourselves. :) Jawge
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Here's my pet peeve.Ny now it's no secret that I wear my Greek ancestry on my sleeve for all to see. I can't stand how people pronounce "feta" cheese. Even though those of Greek ancestry. It's not fetttah. It's feta. Sheesh! Jawge
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BTW I'm feeling the urge to build Joni another bow for this year's shoots. She is shooting a board bow. We travel a lot to go to some. It would be nice for her to have a bow from a log stave. We may be going to a shoot in Grayson, KY. Denton too. Lord willing. I will critically analyze this timing issue as I build her bow. May be I'll report back on it. :) Jawge
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Gotta go. One more thing. IMHO. The bow with zero hand shock has never been built nor will it ever be. :) Jawge
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Marc, a yumi probably have quite a bit handshock due to different return speeds of the limbs, but this is probably not the whole story about handshock, and a yumi might have other caracteristics that skew the picture regarding this one reason for handshock.
George, if you let it down slowly, there is no way the limbs would not reach the braced position at the same time, regardless of wether it pivots :)
Justin: Looking forward to hearing your experimental testing results :)
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If let down quickly, what changes whether the limbs return at the same time, assuming the bow is still free to pivot as in the other scenario?
Colonoscopy is a pita because you have to fast, then purge with strong laxatives the day before. Otherwise it's like take a 20 minute nap, get dressed and go home. Compared to the alternative, it's a small price to pay. I'd encourage folks to research and follow the recommended check-up and monitoring for all kinds of disease. If not, the grim reaper has you on his list, and it's just a matter of time until he gets to your name. I'm 5 weeks post-op after colon re-section to remove cancer (at age 46), looking forward to 5 weeks of radiation/chemo, then another 24 weeks of just chemo. With 90% 5 year survival rate I'm not worried, but sure as hell reformed from the "if I don't go to the doctor I won't get sick" attitude I've had all my life up until now. Had I reacted earlier, to symptoms which probably would have been detected with a yearly physical exam, it would have meant another 20 minutes during the colonoscopy to remove "polyps" and then on with my life. Sorry for the hi-jack, just a topic too close to home for me to let it go by.
Having a burr up your butt is not correctable by any surgery or treatment I'm aware of, and unfortunately the patient typcially has no realization it's such a pita for everyone else.
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The difference could be explained by visualizing a bow beeing dryfired. Then there is almost no resistance slowing the limbs down, which will make it possible for the faster limb to return before the other. As you add up arrow weight, the resistance won't allow the faster limb to use it's extra effectiveness to return as fast. It's perhaps a bit the same like comparing two bows that have the same F/D-curve, but with different effectivity. They will shoot a heavy arrow quite the same, but not a light arrow.
Same thing with a bow that have limbs with different effectivity. The limbs will act quite the same with a heavy arrow/just letting it down, but not with a light arrow/dry fireing. The more efficient limb will return faster.
Was that understandable? My language is perhaps not the best, so bear with me ;D
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Interesting thread guys, I can't add anything useful to your discussion but I am reading it and maybe learning a thing or two in the process :)
As for the primitive thing, for me its like going to a buffet, somedays I just want a salad but the next day I want the ribs. ;D
Same with bows oneday I make a simple bendy handle grease smeared bow, the next I make a gussied up pretty bow, haven't gotten
into laminated bows yet but someday I will. I do use Steve's Mass formula, very useful tool, just like my bandsaw is useful. My last bow
The mass formula isn't a foolproof method to make a bow but it is a very useful tool to set guidelines and the more I understand it,
the more useful it will become. I like these discussions on advanced bow building 101, always something new to learn as long as ya keep yer mind open
to the knowledge. I'm still happy when I get a shooter by whatever means ;D
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Gotta go. One more thing. IMHO. The bow with zero hand shock has never been built nor will it ever be. :) Jawge
But we can sure get closer by examining these topics than ignoring them (even if they are uncomfortable). We may have a different approach to our thinking, but I am sure the "primitive people" discussed what would make a better more efficient bow. Hand shock isn't just uncomfortable, it is wasting energy that should have gone into the arrow.
George, colonoscopy... good advice. I lost a good friend to colon cancer last year that may have lived if he had a colonoscopy. He was only 32. Every 5 years before 50 every 2 after. Justin
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Have you guys ever watched the serious target shooters shoot their bows? The bow always pivots in the hand on release and it always pivots down. What does that tell you?
Sorry guys but this whole idea of limb timing just doesn't hold water to me but that is me and my bows. Maybe others have a hard time with tillering and "timing"
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Interesting topic. Not sure what I believe, or how to express it actually. I think we've all had the experience of tinkering with a bow's tiller with trial and error until the handshock is mitigated. I'd always assumed what was changing was the "limb timing" and to a lesser extent limb mass but I'm open to the idea it is some other factor, or better described using some other terms.
Kviljo,
Yes, understood. Thanks for repeating. It's not so much the time element as it is the bow and arrow being free to return unimpeded.
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Have you guys ever watched the serious target shooters shoot their bows? The bow always pivots in the hand on release and it always pivots down. What does that tell you?
Never seen one pivot. All I have seen hold it so loose that it falls after the tension is gone, but that is entirely different than pivoting. That is a style of gripping to prevent the archer from torquing the bow, has nothing to do with tiller or handshock or the bow for that matter. It is the same for the wheel bow guys also. Justin
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Justin
I've seen several videos of professional target shooters and olympic target shooters where the bow pivots on release. The bow always pivots down
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The ones I have talked to use a strap to keep the bow from falling out of their hand and just let it fall forward. Maybe I missed something. Justin
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Those bows have all kind of stabilizing weigths screwed on the back of the bows,.... always under the handle
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Kvilo,
"George, if you let it down slowly, there is no way the limbs would not reach the braced position at the same time, regardless of wether it pivots."
Ok, if you say so. :)
awge
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This is a great thread for a feature article for PA. Any takers?
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Don, if we could get at least three of us to agree on something it might be LOL. Steve
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Kvilo,
"George, if you let it down slowly, there is no way the limbs would not reach the braced position at the same time, regardless of wether it pivots."
Ok, if you say so. :)
awge
Eh :P
But do you really disagree?
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Yes but...
I don't feel like it. Hey about then Red Sox! :) Jawge
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I have a question. If one limb is faster isn't it also pulling on and slowing down the slower limb.
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Only if it is faster due to being stronger.
If it is faster due to less mass, is it the weaker limb?
If the slower limb is slower due to more mass, is it the stronger limb?
What happens if the faster limb is the low mass and weaker, and the slower limb is high mass and stronger; and they arrive at brace height at the same time on release?
Do you still get handshock?
Sorry to butt in with all questions and no answers.
Cheers, MalV
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I can't say for sure what is happening when a bow has handshock, but I can get rid of it easily and also easily build a bow that doesn't have it. You can just pluck the string most of the time and tell if a bow will have shock or not. Every now and then you may come across one that seems to defy logic and just knocks your teeth loose but if you look hard enough the answer is usuall y pretty simple. Steve
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I guess I'll see if I can tackle it, seeing as how I am opinionated on the subject ;)
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Only if it is faster due to being stronger.
If it is faster due to less mass, is it the weaker limb?
If the slower limb is slower due to more mass, is it the stronger limb?
What happens if the faster limb is the low mass and weaker, and the slower limb is high mass and stronger; and they arrive at brace height at the same time on release?
Do you still get handshock?
Sorry to butt in with all questions and no answers.
Cheers, MalV
If we had all the answears, we would be happy to share them with you. ;D
Faster due to less mass does not mean weaker. Weaker probably means slower. We are talking about efficient vs. not, both limbs being the same draw weight. An overbuilt limb with high mass.
Steve, you are right. They can usually be avoided even if we are unsure what causes the handshock. Justin
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Well I don't know much about the subject but if you take say a light pole 200 lbs 30 foot long. Get two guys and pick it up from each end, it will bend a little through' t the length of the pole making a bow. Hold one end at waist high and drop the other. What happens Is the dropped end hits the ground facilitating the string on a bow I think slapping home to brace hight before the other end does.When that happens the guy holding the other end goes to the hospital more than likely. That pole whip lashes like the hand shock of a 300 lb bow with one wide limb with a carbon arrow spined for a 20 lb bow, and the force on the pole is a freakin tremendous down surge then up surge.Really don't know which way it surge's first but it's painful. It ripples all the way down the pole. I think this is more or less what's happening with a bow that has hand shock. There has to be a physicist out there that can explain all that. Trust me you wont look forward to dropping more than one pole though. ;D
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Talking to Steve I realized something. I have never made a bow over 65" with the exception of my Ipe self bow. It is probably a lot easier to get little handshock when you draw 29" and make shorter bows since all of the limb must be working efficiently. The rigid handles I use also move the bending farther out toward the tips reducing hand shock. Justin
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Justin, I had a boo backed bow last week that had paralell limb most of the way down, very narrow bow barely 1" wide. The shock it gave was very painful but you could barely feel the jolt , just the pain. I narrowed and tapered the sides a bit mid limb and made the tiller slightly more elyptical and the shock virtualy just disappeared. I can even shoot light arrows through it now with no noticeable shock. From what I can see about handshock it seem that using paralell limbs and not tillering elypticaly is almost a guarantee of shock. I think we could easily come up with a sheet / diagram that covered some kind of demensional logic in bows, basicaly how the front view of the bow should correspond to limb thickness and tiller shape. This would hold true for any style bow including elbs, asiatic styles, flatbows and even the native american bows.
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I suspect you are right about a sheet that would help eliminate handshock designs. My first selfbow was parallel to half way up the limb. I tillered it just like the first couple of laminated bows I had made with limbs tapering from fades to tips. It wasn't pleasant to shoot. I didn't even know what handshock was at the time. ;D Luckily I had just discovered PA and posted pictures. Marc told me to take a little more wood off at midlimb. The bow was a pleasure to shoot after that. I learned two lessons from that. One was elliptical tiller on parallel limbs and the other was to be greatfull when guys are critical of your tiller. That was the first thing Marc taught me, but not the last. ;) Justin