Primitive Archer
Main Discussion Area => Bows => Topic started by: coaster500 on July 14, 2012, 03:17:00 pm
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I am at odds sometimes to understand why some of the bows I build are smooth as silk and on the other side another can rattle the caps off my teeth??? I made a 50@27 Osage a while back that shoots very accuratly but will leave a blister on my hand after a few dozen arrows.... Maybe someone here can give me some understanding... The only thing that makes this bow a bit diffenent is a knot on the upper limb about halfway up where I left a bit more material as insurance. The tiller on this one looks good??? Other than that It's pretty much my standard build?
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If tillers good,then it basically boils down to design. To long,to wide at the ends etc...
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Fat strings, string silencers that are bulky or misplaced, arrows under 8-9 gpp. , brace height, limb timing. The tiller may be even but that doesnt mean the tips are getting back home at the same time. Your grip on the bow can do it, keep your grip very loose so the bow can move and the arrow can clear.
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Hawkman, Drums here are a couple pictures so you can see design and the knot in the upper limb.
I have shot arrows up to 780 grains but it still jumps, same string I use on everything... as far as grip if I don't hold onto it it will jump out of the yard!!!
The limbs timing thing might be the culprit with the knot make a wide swath in the working part of the limb??? Ya think???
(http://i28.photobucket.com/albums/c210/coaster500/AgiftfromRalphHardwoodsofmybows004.jpg)
(http://i28.photobucket.com/albums/c210/coaster500/AgiftfromRalphHardwoodsofmybows005-1.jpg)
(http://i28.photobucket.com/albums/c210/coaster500/AgiftfromRalphHardwoodsofmybows001-1.jpg)
other limb
(http://i28.photobucket.com/albums/c210/coaster500/AgiftfromRalphHardwoodsofmybows003-1.jpg)
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I wish I understood hand shock. I have an elbow tendon that tells me my bows need to be smoother. Still looking for that magic design that is smooth, fast, beautiful, cheap and easy. :)
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I dont believe that knot matters much. Working handle bows seem to move a little more than stiff handles. I cant tell what this one is. I dont have a bow that jars me, if I did I may be able to better tell what makes them act as they do? How about a full draw shot KIp Winger.
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IMO it's down to excess mass or too light an arrow.
Obviously the extra mass around knots in character bows will be moving as fast as the bow limb and will cause a jar when it stops.
Similary if the arrow is too light then too much energy remains in the limbs and it jars.
A well shaped cofortable grip helps minimise it, if you can feel the grip at all then it doesn't fit, you should be able to close the hand lightly around it and not be aware of where it's pressing into the hand.
I have a couple of bow that can kick a bit, but going up from a 70gn point to 100gn usually smooths it out.
One of the worst culprits is my only Osage bow, it has static recurve tips and a fair bit of string tension at brace.
Del
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I wish I understood hand shock. I have an elbow tendon that tells me my bows need to be smoother. Still looking for that magic design that is smooth, fast, beautiful, cheap and easy. :)
I get pretty bad tennis elbow too. ELBs are pretty smooth. A nice wide pyramid/paddle is good too. Anything without recurve or an anvil tied to the limbs ;)
I tend to stay below 50#, my fave' is about 47#
Del
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Dell you may be right about the grip (might revisit that) but it still a shocker even with my heaviest arrows!!!
after ten arrows my hand (loose grip) and some of the redness is gone allready!!!
(http://i28.photobucket.com/albums/c210/coaster500/AgiftfromRalphHardwoodsofmybows001-2.jpg)
Full Draw Chris...
(http://i28.photobucket.com/albums/c210/coaster500/Osage%20three%20gentle%20flip%20march%202012/YewBow015.jpg)
and video
http://s28.photobucket.com/albums/c210/coaster500/Osage%20three%20gentle%20flip%20march%202012/?action=view¤t=KipsOsageHunteraftershooting019.mp4
This is the heaviest bow in weight I have built. I built it to hunt and not for target. California Hogs have tough cages and I wanted a bit more pop!!! I have about 5 pounds of weight to play with what would you do to the bow other than revisiting the handle???
I would walk away from this but this is what does when I shoot it!!!
(http://i28.photobucket.com/albums/c210/coaster500/AgiftfromRalphHardwoodsofmybows002-2.jpg)
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What string material are you using? Maybe dacron would cushion it a bit?
Del
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Del It's B-50 ...I use it pretty much on everything???
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Coaster, if you put a gentle curve in the last 12" of the bow I bet your handshock will go a way. It changes the string angle so it may not even gain any weight. Your early draw weight will go up higher and speed right with it. Also fast flight string I feel reduces handshock as well.
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How many ounces does the bow weigh? Whats the draw weight and draw lenth? And how wide is it?
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I second what badger said about fast flight string. It helps a lot with handshock. When Im shooting a new bow in I use a tillering string which is made of b-50 so I can feel every bit of the handshock to know if my limb timing is good, thats the only time I use anything but fast flight.
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The fastflight=less handshock is V interesting.
The received wisdom I'd heard over here was that B50 was softer on the bow and less shocky, not that I took any notice ;D, I just tried a low stretch string and liked it, so that's what I use now (Angel Majesty).
It would be good to findout if FF cures the shock on this one.
So what do we actually think hand shock is ? An impulse or vibration, I spose it's subjective and I don't s'pose anyone has gone to the touble of putting accelerometers on a bow* and shot from a machine with different strings.
I don't s'pose machines get tennis elbow anyhow.
Del
(* I mean a real bow :) not one of these modern target jobs >:( which has doubtless been examined to the nth degree)
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The bow it weighs 1.3 pounds... 62 50@27... and by gentle curve you mean more than this or more?
I can try the fast flight but can't imagine it being that much different.... we will give it a try though
Bow today at rest
(http://i28.photobucket.com/albums/c210/coaster500/Osage%20three%20gentle%20flip%20march%202012/AgiftfromRalphHardwoodsofmybows001.jpg)
(http://i28.photobucket.com/albums/c210/coaster500/Osage%20three%20gentle%20flip%20march%202012/AgiftfromRalphHardwoodsofmybows002.jpg)
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Coaster, maybe a couple of inches more, big difference with fast flight.
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why not post one of your vidios shooting the bow, get a look at how she's working, Bub
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why not post one of your vidios shooting the bow, get a look at how she's working, Bub
I did Bubby but here it is again... for some reason it's a link not a picture link???
http://s28.photobucket.com/albums/c210/coaster500/Osage%20three%20gentle%20flip%20march%202012/?action=view¤t=KipsOsageHunteraftershooting019.mp4
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Just a thought! Not sure about this but the last Osage bow I built was design from TBB. After tiller was done and I started shooting it , it had awful hand shock. So I put it aside and studied the situation. After a month or so I took the bow back to the target and shot it every day for a couple of weeks and to my surprise the more it was shot the less hand shock it had! today it shoots fine. I suppose it just needed to be broke in !
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I would say you need to get more bend out of the outer limbs. The way I see it for your width profile the outer limbs definately need more bend. Look at where the set is on your bow - inner limbs. I have found sticking to the 'mantra' in the TBB's of tillering your bow so that there is no set in the inner limbs, a little mid-limb and the rest out to the tips will give you a shockless bow. Basically there is extra wood on your bow that isn't doing anything.
I would re-tiller it by reducing the width from around mid-limb out to the tips. Make your tips 3/8ths wide. If you find that reducing the width hasn't helped the out limb bend then do a little scraping on the thickness. GO SLOWLY though with plenty of exercising between reductions.
I always use fast flight (dyneema) strings and have never had a problem with them.
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I would say you need to get more bend out of the outer limbs. The way I see it for your width profile the outer limbs definately need more bend. Look at where the set is on your bow - inner limbs. I have found sticking to the 'mantra' in the TBB's of tillering your bow so that there is no set in the inner limbs, a little mid-limb and the rest out to the tips will give you a shockless bow. Basically there is extra wood on your bow that isn't doing anything.
I would re-tiller it by reducing the width from around mid-limb out to the tips. Make your tips 3/8ths wide. If you find that reducing the width hasn't helped the out limb bend then do a little scraping on the thickness. GO SLOWLY though with plenty of exercising between reductions.
I always use fast flight (dyneema) strings and have never had a problem with them.
After watching the video and laying this bow side by side with others I think you hit the nail on the head Mike... fastflight might help as well as curving the tips but that would not fix the basic problem... I think I got to conservative with wood removal around the knot and carried it through the whole bow.
Thank you all
Kip
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... so that's 'excess mass' then? O:).
Del
(Don't I get a gold star, saucer of milk or summat? ;D)
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Del, lots of design elements contribute to handshock but one thing we all know is that it is energy left in the bow not used by the arrow. The limbs have momentum in them when they move forward, the only thing holding them back is the arrow. The lower the outer limb mass the less momentum obviously. Also we can incorporate design elements that give the arrow better leverage over the limbs as we see in recurves and r/d bows. Idealy the limb tips will come almost to a stop right before the arrow leaves the bow. If the limb tips come to a stop before the inner limb which is very common in tillers where we get the whole limb bending, we feel a rattle type shock. If the limbs all come forward at almosty the same time like we might see in an elb type arc of the circle tiller we can get a teeth rattling jolt. The string angles respong not just to the limb tips but to their relation to the entire bow limb throughout the draw. If the outer limb starts to flex first and then the bend works it's way inward and lastly bends up to the fades I believe it will have less shock because as it unwinds all the arrow is trying to hold back are the tips.
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Thanks Badger, V lucid explanation.
I'll have to try an r/d laminated design. I have some Oregon Yew billets with borer damaged sapwood and a length of boo which keep calling me to the workshop ;D.
Del
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... so that's 'excess mass' then? O:).
Del
(Don't I get a gold star, saucer of milk or summat? ;D)
That cup of milk might spoil crossing the pone but send me an address and I think I can manage a GOLD STAR :laugh:
Del, lots of design elements contribute to handshock but one thing we all know is that it is energy left in the bow not used by the arrow. The limbs have momentum in them when they move forward, the only thing holding them back is the arrow. The lower the outer limb mass the less momentum obviously. Also we can incorporate design elements that give the arrow better leverage over the limbs as we see in recurves and r/d bows. Idealy the limb tips will come almost to a stop right before the arrow leaves the bow. If the limb tips come to a stop before the inner limb which is very common in tillers where we get the whole limb bending, we feel a rattle type shock. If the limbs all come forward at almosty the same time like we might see in an elb type arc of the circle tiller we can get a teeth rattling jolt. The string angles respong not just to the limb tips but to their relation to the entire bow limb throughout the draw. If the outer limb starts to flex first and then the bend works it's way inward and lastly bends up to the fades I believe it will have less shock because as it unwinds all the arrow is trying to hold back are the tips.
Badger, thank you for that breakdown.... when you are relatively new at this stuff and flying for the most part by the seat of your pants, copying blended with a bit instinct it's nice when someone says something that turns the light on :)
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An interesting thread. thanks guys - very informative. I think I am going to start scraping away at the tips of some of my previous bows which are on the "this damn thing hurts when I shoot it!" list.
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Sorry I'm a little late to see this !
Just to look at that thing makes my whole arm hurt !
most of the work is inboard with way to much weight outboard = ouch !!!!
Glad the folks could set you to fixing it !!
Guy
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3 Things causes hand shock.
The tips have to much mass.
The tillers not correct and one limb finishs before the other.
Bendy handles. Bendy handle bows have more hand shock that stiff handle bows.
There a few other things that causes a little.
Lighter the bow the more hand shock the bow has. Again mass has little over all to do with it.
To light a arrow alows more hand shock into the bow. Heavyer arrows alows more of the bows engery to go into the arrow and not into the handle. Again it's not enough to be a lot.
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Generally speaking the only thing that will give a bow, by itself, excessive hand shock is too much outer limb mass. The worse offender is having the inner limbs doing all the work and the outer limbs stiff and unbending. When the string slams back home any energy that remains in the bow will travel down the limbs making them bow outwards. If most of the limb is working then this remaining energy will be distributed throughout the limb with very little handle movement. If the only part of the limbs that are actually working is near the handle then this will concentrate the remaining energy in that area and tend to make the handle bounce back and forth in your hand.
Limb timing has been talked about before but this is very ambiguous. Unless your bow making skills are very pour you should be able to easily tell whether one outer limb has more mass than the other and that is one of the very few things, if not the only thing, that can actually affect limb timing. The other thing that may affect limb timing is having one limb much stronger than the other and this is also something that is very noticeable, this one is very iffy though as a stronger limb would have more mass which would tend to slow down it's return making it pretty well the same as the weaker limb.
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Generally speaking the only thing that will give a bow, by itself, excessive hand shock is too much outer limb mass. The worse offender is having the inner limbs doing all the work and the outer limbs stiff and unbending. When the string slams back home any energy that remains in the bow will travel down the limbs making them bow outwards. If most of the limb is working then this remaining energy will be distributed throughout the limb with very little handle movement. If the only part of the limbs that are actually working is near the handle then this will concentrate the remaining energy in that area and tend to make the handle bounce back and forth in your hand.
Limb timing has been talked about before but this is very ambiguous. Unless your bow making skills are very pour you should be able to easily tell whether one outer limb has more mass than the other and that is one of the very few things, if not the only thing, that can actually affect limb timing. The other thing that may affect limb timing is having one limb much stronger than the other and this is also something that is very noticeable, this one is very iffy though as a stronger limb would have more mass which would tend to slow down it's return making it pretty well the same as the weaker limb.
Thats why you get paid the big bucks !!
I do not know what some of those words are but ,I think you are correct Marc !!!
No one has proved to me that(Limb timing) even matters ,If there is such a thing .
Keep it simple
Keep it fun !!
Guy
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I think their may be two kinds of limb timing. If one limb is faster than the other limb the slower limb will just hold back the faster one and they will still finish at the same time. But I do believe in timing within the same limb and how it unfolds. I believe a limb tip can finish before the inner limb.
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Good point Steve but that would necessitate that the one limb have a different tiller shape than the other and that would be noticeable.
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Thanks guys for your comments... looks to me that there are several issues to address that "Might" cause the shock. I am going to address the mass issue on this bow, as it seem to be the most obvious. I will post my results.
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In another thread I posted on how I used the tillering gizmo to lower the draw weight on several bows just because I was in a hurry. Besides a significant drop in performance they all picked up a bit of handshock, not all that bad but noticeable. None of these bows were thick in the outer limbs, most of them had the last 12" narrowed down pretty good. I blamed the circular tiller of the inner and mid limb, outer limb is stiff.
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In another thread I posted on how I used the tillering gizmo to lower the draw weight on several bows just because I was in a hurry. Besides a significant drop in performance they all picked up a bit of handshock, not all that bad but noticeable. None of these bows were thick in the outer limbs, most of them had the last 12" narrowed down pretty good. I blamed the circular tiller of the inner and mid limb, outer limb is stiff.
What is the front profile of the now shocky bows? Is this a case of the circular tiller brought about by the use of the gizmo imposed on a parallel limbed bow causing parts of the limb to move at different rates as speculated above? We need someone to now invent a gizmo that gets shorter the nearer you get to the end of the limb ;-)
Peter