Primitive Archer
Main Discussion Area => Bows => Topic started by: sleek on October 24, 2020, 06:05:52 pm
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What are the things that can cause hand shock? Too big of tips I know, too much inner limb bending and off timed limbs. What else can cause it?
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Im having trouble with a bow that has hand shock so bad it feels like my index finger got hit with a hammer. Never had it that bad. So I checked the limb timing and saw the upper limb was too stiff mid limb. I got that matched to the lower and it got so much worse I considered hitting the bow with a hammer. I dont appreciate that much pain.
So I took the scraper to the lower limb and weakened it. That got the shock under control. But still its at levels I dont accept. Im going to keep messing with the tiller little at a time until I get it right or it ceases to be a bow.
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What design of bow is it(stiff or bend through the handle?), how wide is the handle, does it have any padding at the grip?
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I think you about hit the main ones, sleek.
But a bend in the handle bow does not necessarily have hand shock. It all depends on how much the handle bends.
Also, to add, the last 8" or so should be as narrow as possible.
Jawge
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No padding at the grip. Stiff handled basic straight bow. 1.5 inches wide from the fade out to 7 inches, then tapers down to the tips.
I got it now down to 45#@28, it was 45@26. The lower limb was stiff by a half inch and is now weak by a quarter. Its now more friendly on the hand. Im going to drop the lower limb a touch more and see if that gets it better.
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I think you about hit the main ones, sleek.
But a bend in the handle bow does not necessarily have hand shock. It all depends on how much the handle bends.
Also, to add, the last 8" or so should be as narrow as possible.
Jawge
Thanks Jawge, I leave the last 7 stiff and narrow, I forgot to add that
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so if you set it in the tiller tree with the pressurepoint at the saddle about where it is in the hand, and the nock point on the string about like you shoot it, does it rock when you pull? or rock in the hand when you shoot it?
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if the bow has too much mass weight,, or is overbuilt quite a bit, it will be shocky,,
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so if you set it in the tiller tree with the pressurepoint at the saddle about where it is in the hand, and the nock point on the string about like you shoot it, does it rock when you pull? or rock in the hand when you shoot it?
I've never been able to get an accurate answer from doing what you described, because it changes based on where I nock the arrow, and changing the nocking point hasn't had an affect on the shock. I can tell you its now within limits after getting the lower limb more weak than the upper, and thats odd in itself.
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what is the mass weight of the bow,, and does it come close to the chart in volume 4
I have found this to be the main cause of shock in my bow building,,
when you say weaker, is that at full draw,, or at brace
ok Im just guessing cause I dont know how long the bow or draw,,
but if you cut it shorter and narrow the limbs, it will reduce the shock,,
or if you just side tiller to reduce the weight,,
its gonna shoot better with positive tiller,,,, maybe it is positive at full draw,,
a heavier arrow will help too,,
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Badly shaped grip... especially with laminated bows where the back is dead flat and the corners dig into your knuckle.
Arrows too light!
Del
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Shoot the bow upside down and see what happens. I think limb timing is the culprit in most cases, things may measure out just fine but the limbs can still have different return rates.
Without seeing the bow, I am only guessing.
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There was a big debate here on hand-shock/limb timing several years ago. Many were pointing at limb timing as the issue, I have never bought into that one. I have come to believe that the way the limbs bend is part of the problem. What I mean by that is having a bow with one limb that bends more mid-limb with the other limb bending more closer to the handle. There should be symmetry in the way the limbs bend, when possible.
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What I mean by that is having a bow with one limb that bends more mid-limb with the other limb bending more closer to the handle. There should be symmetry in the way the limbs bend, when possible.
Mark,
I presume you could easily see this on a tiller tree at full draw?
There was a big debate here on hand-shock/limb timing several years ago
http://www.primitivearcher.com/smf/index.php/topic,6187.0.html (http://www.primitivearcher.com/smf/index.php/topic,6187.0.html)
or
http://www.primitivearcher.com/smf/index.php/topic,46111.0.html (http://www.primitivearcher.com/smf/index.php/topic,46111.0.html)
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Try raising the brace height a little...
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I have found that limb bending anomalies are usually the problem also, I call this timing as it has to to with the return rate. These can be so small you wouldn't think they will matter but they do, a gizmo will sort them out.
I just made a billet bow with vastly dissimilar limbs, one was rock hard the other was mushy. I thought the billets matched when I pulled them out of the pile, they didn't.
This bow was shocky and shot a corkscrew arrow, I sanded here and there and tweaked this and that for a month. I went to positive and negative tiller, nothing worked.
After I put about 1000 arrows through it it magically fell into line on its own and is now one of my best shooting bows.
Talk about miss matched billets, the yellow billet is rock hard, the red one is soft;
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Eric how do you think they balanced out, what does the tiller look like now?
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Almost all selfbow tillers change over time until they settle in, some never do and may need tiller tweaking every few years. I have both kinds of bows in my stable.
Just a guess but I think pulling the bow from the same point every time possibly stressed one limb over the other and mellowed out the limb with the fast return.
I have had bows with a slight propellor straighten out over time just from being shot a bunch. Apparently the stiff limb side gets more stress and loosens up.
The tiller is 1/8" positive on the top limb, my gizmo set with 1/16" of pencil showing won't mark the limbs, I shoot split finger.
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You should be able to see the difference from brace to full draw, stands out more at full draw
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Three things that I take into account:
Make sure the arrows are MATCHED to the bow. So often we as bowyers (I am absolutely guilty) have a bin of mismatched arrows that we use for testing and shooting bows and the fact is that an arrow that isn't properly matched to a given bow will not leave the string with as much energy as it could/should and that left-behind energy will show up as noise and shock.
Make sure the brace height is high enough. I have shot many bows that seemed awful at a given brace height, but were amazing with just a 1/2" change in brace. I think anything you can do to alter the dynamics of the system is worth trying and brace height is probably the easiest. Also, B50/55 strings will be less shocky than 452X or similar all else being equal.
Use your cell phone to help you. Most modern smart phones have a "super slo mo" video camera mode that works amazingly well for watching HOW a bow acts during the release and firing process. You can watch the limbs act and stop the video to see how they are working during the shot. This works well
Matt
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Start your taper at mid limb that removes lots of mass . It will add speed and reduce shock. Just an opinion. Arvin
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I made more than 100 bows in the first few years, then slowed down because I like shooting. But I have never noticed hand shock in any of my bows. I think it's because I hold them only against the heal of my hand when I shoot. The fingers and thumb do nothing.
Years back somebody want me to shoot his Howard Hill (forget which model). He said it was real shocky. I shot it and didn't notice any hand shock. He then said to grip the bow. The next shot jarred my whole arm and shoulder. I shot the bow some more with a loose grip and found it to be a very nice shooter.
Draw your own conclusion....
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I made just a few bows but one had really awful handshock, from the wrist through elbow to the arm joint. I narrowed upper midlimb a bit and it improved half, then I cut off an inch off each end to keep the poundage and it improved 100%. I converted it into half pyramid. As someone skilled wrote here, front shape must conform side shape of the tiller. I hauled useless material forward at the shot.
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yes and you reduced the mass weight per poundage of draw
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How long is the bow and how long is the draw? I had a sinew backed osage bow that I thought had a perfect tiller, Narrow tips and a stiff handle. I could not figure out why there was still handshock. The bow was 63" long and drew 60# @ 31". It was Badger that pointed out that even with the whole limb bending evenly throughout, all that bend returning to brace when the arrow was released was the reason for the shock.
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Its 63" ttt and pulls 45@28.I will post some pics later today of it. Uts still got hand shock but no where near as bad after making the lower limb weaker. Id sure like to understand this better.
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are you getting good arrow flight with weaker limb on bottom, and does it appear weaker at full draw,,
Sleek you still didnt say what the mass weight was,, it could be a consideration,, in what you are feeling,, or a combination of several things,, a soft double layer of leather on the handle can help percieved hand shock,,
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even with the whole limb bending evenly throughout, all that bend returning to brace when the arrow was released was the reason for the shock.
Chuck, How did that limb return different from any other limb? I am having difficulty understanding
thanks
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The only bows I ever had with handshock were the ones that appeared to have perfect tillers on them. I have never heard anyone at the flight shoots talking about shock even shooting little 200 grain arrows. I think too much limb returning to brace at the same time like on a perfectly circular tiller.
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a stiff handled pyramid bow with perfectly circular tiller on each limb?
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My pyramid bows have no shock. Are they perfect no. Arvin
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I have been making self bows,, for me and others for bout 30 years,,,so have felt vibration in varying degress,, if you are used to shooting a sinew bow with no hand shock ,, and then shoot a longer self bow you might feel it a bit, but when you get used to the longer self bow it becomes a non issue,,for me the sinew bows are the smoothest consistantly,, they are light as a feather and a wisper to shoot,,
a longer self bow has a bit of vibration,, and I guess if you not used to it might find it offencsive,, but like said above ,, usually if you use a lite grip,, its will tame it,,
i know you guys tired of hearing me talk about the mass weight,, but even Badger stated with light arrow and flight bow no one complains, but I promise you those bows are on the edge,,, and dont have any extra mass weight to cause vibration,,
thats all I know,, if you put a thicker leather handle and shoot a heavier arrow you can almost tame anything,, and lots of fine tune tweaks that will help,,,, but a really well made bow ,,,rarely has hand shock,,, but like anything with wood bows,, they can break the rules a prove you wrong every time if you try to make a hard fast rule,,,
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The perfect tiller hand shock I will note comes from bows that draw around 50% of their length, not longer ones.
I never really noticed hand shock until I started making bows with less and less of it. Kind of a subjective thing.