New Turkish hornbow
Hi guys, here are a couple of pictures of my latest Turkish bow.
I'm hoping i've learnt the lessons that my first few attempts at these bows have taught me.
This bow has slightly longer sals, the thinnest spot is closer to the kasan eyes and the reflex in the core at the kasan eyes is lower, the sinew is flatter than before and the belly more rounded and finally my tips are a little shorter. My first bows have all suffered from instability problems hence the above changes.
Any advice on the shape, amount of bending at the kasan eyes etc would be gratefully accepted. This bow has shown only a tiny bit of twist at one kasan eye so far which was corrected only with pressure, if it keeps showing up during stringing i'll use a little heat on it. One limb was also a little stronger but a few scrapes has sloved that. So far i'm very happy with as it was perfectly stable when first strung.
I'm hoping i've learnt the lessons that my first few attempts at these bows have taught me.
This bow has slightly longer sals, the thinnest spot is closer to the kasan eyes and the reflex in the core at the kasan eyes is lower, the sinew is flatter than before and the belly more rounded and finally my tips are a little shorter. My first bows have all suffered from instability problems hence the above changes.
Any advice on the shape, amount of bending at the kasan eyes etc would be gratefully accepted. This bow has shown only a tiny bit of twist at one kasan eye so far which was corrected only with pressure, if it keeps showing up during stringing i'll use a little heat on it. One limb was also a little stronger but a few scrapes has sloved that. So far i'm very happy with as it was perfectly stable when first strung.
The un-strung picture is immediately after being strung for about 30 mins.
Great hero ... Big man you are, if you have the courage to kill animals for fun and glory. congratulations
Nice shape, quite "conservative". I would lower the brace height.
Stilian, what are you trying to say?
Stilian, what are you trying to say?
Fun and glory??? Well you are welcome to your opinon however wise people reserve judgement until they know the facts. We have a saying - ' don't judge a book by its cover'.Stilian Stefanov wrote:
Great hero ... Big man you are, if you have the courage to kill animals for fun and glory. congratulations
Indeed it is conservative :D That was my intention with this bow. It is braced around 7 1/2 inch in that photo and i'm pretty sure it is stable enough 'as is' to be fine with a lower brace. I have made it with the intention of being able to shoot it at field archery competitions where it will be strung all day.Alessi Francesco wrote:
Nice shape, quite "conservative". I would lower the brace height.
Stilian, what are you trying to say?
Excuse me, but when he saw the animal cruelty I get nervous ...
What cruelty? Do you mean the use of animal materials? Are you the same guy that made the bulgarian bow? Did you have some kind of vegan conversion in the last few months? Anyway, I don't think that this is the right forum for you: if you are offended go somewhere else.
Francesco
Francesco
Francesco, it's not about that, mikekeswick was uploaded photos of him dead squirrels and birds with a slingshot but i apologized for his reaction. I apologize again. Yes, I'm the one who made the Bulgarian bow, and this forum is just for me.
Here is a picture of the bow drawn to 21 inches.
I keep hearing a bit of a noise from the top limb.....i've looked very closly and there are no signs of delamination. I really can't figure it out other than it only happens when drawn to around 20 and doesn't do it every time it's drawn??
http://i492.photobucket.com/albums/rr28 ... kish21.jpg
I keep hearing a bit of a noise from the top limb.....i've looked very closly and there are no signs of delamination. I really can't figure it out other than it only happens when drawn to around 20 and doesn't do it every time it's drawn??
http://i492.photobucket.com/albums/rr28 ... kish21.jpg
I'm thinking that possibly it's just the string catching on the side of the tip during the draw. I will check if that is the problem after some food!
Without being there it is hard to be accurate, but do you think you might be putting a little twist into the bow from the bow hand. I am not talking about major distortion.
Congrats, good work. Kasan looks short, there is no big stress in your bow so it can stay strung for a long time.
Cem
Cem
Interesting bow! I'd also lower the brace height a little, although I'm sure it would not need it because of stress. Don't they say that bows like this one, with short kasans, perform better at lighter draw weights?
How would you say the stacking in this one compares to the other turkish bows you've made? I suppose some extra stacking from the geometry of the bow would be countered by the extra reflex it ought to keep?
How would you say the stacking in this one compares to the other turkish bows you've made? I suppose some extra stacking from the geometry of the bow would be countered by the extra reflex it ought to keep?
Bede - I think you may be right as it only made the noise when I drew it to take photos of the tiller. I normally shoot with quite a cant to the bow so perhaps the act of drawing it straight up and down caused me to tourque it slightly?
Scemdonmez - Thanks, I finally feel like I am starting to get to know what i'm doing with these bows.
Kviljo - I haven't drawn it far enough yet to know where it starts to stack. I've had it back to 24 and there is no stack yet. I suppose really it should be drawn to 28. I'm going to take it slowly now.
The other bows i've made have any been too reflexed and thick at the kasan eyes so the limbs have more string follow than this bow and also had stability problems - I still haven't quite tamed the first successful bow yet!
I have been a little lucky with this bow as it has needed very little correction or tillering.
Scemdonmez - Thanks, I finally feel like I am starting to get to know what i'm doing with these bows.
Kviljo - I haven't drawn it far enough yet to know where it starts to stack. I've had it back to 24 and there is no stack yet. I suppose really it should be drawn to 28. I'm going to take it slowly now.
The other bows i've made have any been too reflexed and thick at the kasan eyes so the limbs have more string follow than this bow and also had stability problems - I still haven't quite tamed the first successful bow yet!
I have been a little lucky with this bow as it has needed very little correction or tillering.
Sometimes accidents of one's physiology can cause some interesting experiences drawing a bow. Since I am five foot four, if I draw an arrow to my earlobe with a thumb draw, the length works out to be twenty eight inches. This caused some amusing exchanges between Adam Karpowicz and me because he had measured a bow I was using and it started stacking at 26 inches. When I drew it to 28, it seemed incredibly smooth. Adam was right of course since he had made objective measurements with a ruler and a scale. What I had experienced is the subjective feeling caused by the change of physical geometry when my shoulders started to form a straight line with my upper arms. This increased stability gave me the impression the bow was as easy to draw as in the earlier part of the process.
I think there might be an important design criterion for recurved, eared bows. Many bows made with modern materials end their draw with the ears almost vertical and the angle to the string between 45 and 55 degrees to the tips. As the bow approaches full draw on traditional bows like Turkish and Persian bows, the string angle inches up towards 80 degrees, sometimes the full 90 degrees where the leverage stops further drawing on all but the lightest bows. This combined with the straightening of the shoulders and lining up of the arms produces a very stable body shape to hold the bow at full draw. Because the archer is not being stressed by perceived stacking, aiming and releasing are made easier. There maybe other advantages to this physical geometry that bowyers and experienced archers have noticed.
I think there might be an important design criterion for recurved, eared bows. Many bows made with modern materials end their draw with the ears almost vertical and the angle to the string between 45 and 55 degrees to the tips. As the bow approaches full draw on traditional bows like Turkish and Persian bows, the string angle inches up towards 80 degrees, sometimes the full 90 degrees where the leverage stops further drawing on all but the lightest bows. This combined with the straightening of the shoulders and lining up of the arms produces a very stable body shape to hold the bow at full draw. Because the archer is not being stressed by perceived stacking, aiming and releasing are made easier. There maybe other advantages to this physical geometry that bowyers and experienced archers have noticed.
I have had another tillering session on this bow and I have found a patch in the sinew that hasn't bonded properly. When you tap it with your finger you can hear that there is some sort of delamination in the sinew layer.
I am at a loss for what to do next.
Obviously I need to get some glue in there...but how? There are no cracks or other ways to get glue in there. I don't think it's delaminated from the core itself more just a minor delamination between sinew layers. Maybe some glue gelled before the sinew was correctly laid down or it was starved of glue. I really don't know.
The hollow sounding patch is about 2 inches long and only appears to be in the center of the limb.
Any ideas?
I am at a loss for what to do next.
Obviously I need to get some glue in there...but how? There are no cracks or other ways to get glue in there. I don't think it's delaminated from the core itself more just a minor delamination between sinew layers. Maybe some glue gelled before the sinew was correctly laid down or it was starved of glue. I really don't know.
The hollow sounding patch is about 2 inches long and only appears to be in the center of the limb.
Any ideas?
Use a syringe!
I was advised by someone to inject glue using a syringe, into a bit of sinew back that had started to delaminate. I didn't bother, since the bow had failed for other reasons by that stage. An idea though perhaps?
I was advised by someone to inject glue using a syringe, into a bit of sinew back that had started to delaminate. I didn't bother, since the bow had failed for other reasons by that stage. An idea though perhaps?
Yes I know but the sinew layer is to compact to get a syringe into the 'unstuck' bit. I've already tried and the needle just gets bent.
An small incision can be made (with a sharp knife or scalpel) into the sinew to reach the pocket. Cut along the fibers, parallel to the arms. Then it should be possible to deliver the glue with a syringe.
Adam
Adam
Thank you. I've been hoping there was a way to fix this as apart from this problem the bow appears, to me anyway, to be perfect.
How long should I leave it to dry? Presumably it will depend on how deep the unbonded section is? I intend to make a 'bath' that the limb can fit in and then I can immerse the limb and flex it to suck the glue in.
How long should I leave it to dry? Presumably it will depend on how deep the unbonded section is? I intend to make a 'bath' that the limb can fit in and then I can immerse the limb and flex it to suck the glue in.
Oh and it appears to be bending a little too much at the unbonded section. If I am sucessful in getting this section glued do you think that perhaps it will 'stiffen' this area?
If this section became weak, then the repair must really be successful. First it is necessary to make sure the pocket is indeed open under the incision, You can try to lift the edges of the incision to make way for the glue.
When the section is dipped in glue and the flexing shows the bubbles coming in and out, there is a good chance of success. I usually clamp with some kind of padding that conforms to the surface of the section and does not create a dent (the sinew and glue, now wet, are quite soft). I once made an epoxy mould for a section of kasan, or carved a good match of wood. A few pieces of thick paper will provide more padding under the mould. The paper will stick, but it can later be scraped off.
I suggest to keep the clamps in place for one day, then replace the paper and clamp again for several days. Then at least a month to dry before tillering.
Adam
When the section is dipped in glue and the flexing shows the bubbles coming in and out, there is a good chance of success. I usually clamp with some kind of padding that conforms to the surface of the section and does not create a dent (the sinew and glue, now wet, are quite soft). I once made an epoxy mould for a section of kasan, or carved a good match of wood. A few pieces of thick paper will provide more padding under the mould. The paper will stick, but it can later be scraped off.
I suggest to keep the clamps in place for one day, then replace the paper and clamp again for several days. Then at least a month to dry before tillering.
Adam
Thanks again.
I did the repair last night and am hoping that it will be sucessful.
I scored some lines in the sinew and then flexed the limb, the unstuck section started to lift when I flexed the limb. Then I applied some glue and again flexed the limb and the glue was sucked in well. I think that I have got all of the loose section. I used some leather shims to make sure I got good contact/clamping and I used a small piece of rope wrapped around and around for the clamping pressure as clamps weren't going to be so effective.
I will let everyone know how it went when I bend it again! I really hope this has fixed it as this is my first bow with zero stability problems.
I did the repair last night and am hoping that it will be sucessful.
I scored some lines in the sinew and then flexed the limb, the unstuck section started to lift when I flexed the limb. Then I applied some glue and again flexed the limb and the glue was sucked in well. I think that I have got all of the loose section. I used some leather shims to make sure I got good contact/clamping and I used a small piece of rope wrapped around and around for the clamping pressure as clamps weren't going to be so effective.
I will let everyone know how it went when I bend it again! I really hope this has fixed it as this is my first bow with zero stability problems.