Practice Bow in Progress
I am making a composite bow in the general style of an Asian design, but without following any particular plans and using some non-traditional materials such as resorcinol glue and gemsbok horn.
Here is a link to some pics of what I have done so far.
http://s96.photobucket.com/albums/l200/ ... ite%20Bow/
Core is bamboo. Slight backset in the handle, no other bending of the core. Siyahs are black walnut, 4" v-splice, mild recurve design that is cut and not heat-bent. Belly is gemsbok horn made from two pieces spliced along the length of the belly (see other thread) and glued with resorcinol glue. I used only half of one gemsbok horn by doing it this way. The horn strips are about 11.5" long, just covering the working limb and not the handle nor the v-splice. Those areas are bolstered with wood. Handle area has walnut on back, osage on belly. Bow was sinewed with deer leg sinew, using Knox gelatin glue. Sinew covers the handle area and v-splices, it does not go over the sides of the limbs.
I am waiting now for the sinew to dry and cure. The hardest part! I believe I will wrap the fades and v-splice areas (where the horn starts/stops) with heavy thread and glue for reinforcement and to keep the laminations from separating. I am also contemplating covering most of the bow in silk, for looks and for some slight additional structural integrity.
This bow is simply for practice/experience, I plan to make a bow of all traditional materials/construction in the future.
Here is a link to some pics of what I have done so far.
http://s96.photobucket.com/albums/l200/ ... ite%20Bow/
Core is bamboo. Slight backset in the handle, no other bending of the core. Siyahs are black walnut, 4" v-splice, mild recurve design that is cut and not heat-bent. Belly is gemsbok horn made from two pieces spliced along the length of the belly (see other thread) and glued with resorcinol glue. I used only half of one gemsbok horn by doing it this way. The horn strips are about 11.5" long, just covering the working limb and not the handle nor the v-splice. Those areas are bolstered with wood. Handle area has walnut on back, osage on belly. Bow was sinewed with deer leg sinew, using Knox gelatin glue. Sinew covers the handle area and v-splices, it does not go over the sides of the limbs.
I am waiting now for the sinew to dry and cure. The hardest part! I believe I will wrap the fades and v-splice areas (where the horn starts/stops) with heavy thread and glue for reinforcement and to keep the laminations from separating. I am also contemplating covering most of the bow in silk, for looks and for some slight additional structural integrity.
This bow is simply for practice/experience, I plan to make a bow of all traditional materials/construction in the future.
Lennie,
Have you considered covering the the splices with a sinew binding rather than a thread wrapping? It would be lighter and less bulky.
Have you considered covering the the splices with a sinew binding rather than a thread wrapping? It would be lighter and less bulky.
That was my original intention. I didn't think there would be much mass difference between thread and sinew, so I was going to go with the less precious resource. But I do have some deer backstrap sinew already processed, that would work. You have found the thread/glue to have significantly more mass? I was not going to "pile it up", simply wrap one or two layers worth in the region of the v-splice. Mass out there, would have some effect on performance. But as a percentage of the total mass of the siyahs, I wouldn't think it would make a huge difference. I'm a newbie to this though and certainly value experienced suggestions.
I did run sinew up over the splices as part of the backing. And the siyahs themselves have an arched construction even in the v-splice area to give them more stiffness. Still, I need to hold down the ends of the horn, and the sinew backing. And I worry about both this area, and the handle area. I think that is where a failure will occur, in these place that go from bending to nonbending. Lots of stress concentrated in relatively small areas.
I did run sinew up over the splices as part of the backing. And the siyahs themselves have an arched construction even in the v-splice area to give them more stiffness. Still, I need to hold down the ends of the horn, and the sinew backing. And I worry about both this area, and the handle area. I think that is where a failure will occur, in these place that go from bending to nonbending. Lots of stress concentrated in relatively small areas.
Lennie,
It all depends on how much thread you wind around your splices. The current trend in Hungarian bows is a little excessive. Sinew weight for weight will probably stronger and it has the advantage of putting the joint under compression as it dries.
I have done some experimentation with compression contruction and have found they have interesting properties. However, many of the contributers to this forum know much more about bow construction than I do.
The Khotan bow had sinew wrapping than seemed a good example.
It all depends on how much thread you wind around your splices. The current trend in Hungarian bows is a little excessive. Sinew weight for weight will probably stronger and it has the advantage of putting the joint under compression as it dries.
I have done some experimentation with compression contruction and have found they have interesting properties. However, many of the contributers to this forum know much more about bow construction than I do.
The Khotan bow had sinew wrapping than seemed a good example.
I will go with sinew then, I think you are right about the compression helping to holds things together better.
I'll especially need it at the fades, because my wooden "spacer" that is in between my horn, has come loose on one end. I almost hope the whole piece pops off when the sinew on the limbs shrinks and adds some reflex. If not, I'll just reglue and then wrap for added strength.
I'll especially need it at the fades, because my wooden "spacer" that is in between my horn, has come loose on one end. I almost hope the whole piece pops off when the sinew on the limbs shrinks and adds some reflex. If not, I'll just reglue and then wrap for added strength.
A few new pics in the link above, one unbraced, one at brace equivalent and one at a bit of draw using a long string.
I fixed my handle piece that was loose on one end. I simply used a hacksaw to cut off the part of the wood that didn't stick, then repreped the surfaces and glued it back on with an additional wedge of wood to take up the slack from the kerf. Things seem sound now.
I also cut in some temporrary nocks and have been pulling the bow a bit with a long string. I'm worried that the nocks might split out so I intend to reinforce them with some horn.
I made some tepliks (sp?) and was only slightly successful in using them, I had trouble getting the ropes to hold the limbs tightly. It worked but the bow wasn't in a position where I could string it. I decided to try the long string just to see what the bend is like. The poundage is going to be fairly high on this bow, I suppose I should've gone a bit thinner on the core. And my angles on the siyahs, are a little less than I think they should be. But it is holding together so far.
I attempted to string it using my long string as a stringer. I made a temporary string out of nylon cord but it stretched when I got it on the bow. I'll try making a string out of linen now that I have some idea of how long it needs to be. I have some linen shoemaker's thread that is pretty strong stuff, I found it at an antique shop.
Which brings me to my question of the day, how do you make a string? I was just doubling the ends over and tying an overhand knot so the loop was about 5" long. I'll do a search but if anyone has tips or a link you can let me know.
I fixed my handle piece that was loose on one end. I simply used a hacksaw to cut off the part of the wood that didn't stick, then repreped the surfaces and glued it back on with an additional wedge of wood to take up the slack from the kerf. Things seem sound now.
I also cut in some temporrary nocks and have been pulling the bow a bit with a long string. I'm worried that the nocks might split out so I intend to reinforce them with some horn.
I made some tepliks (sp?) and was only slightly successful in using them, I had trouble getting the ropes to hold the limbs tightly. It worked but the bow wasn't in a position where I could string it. I decided to try the long string just to see what the bend is like. The poundage is going to be fairly high on this bow, I suppose I should've gone a bit thinner on the core. And my angles on the siyahs, are a little less than I think they should be. But it is holding together so far.
I attempted to string it using my long string as a stringer. I made a temporary string out of nylon cord but it stretched when I got it on the bow. I'll try making a string out of linen now that I have some idea of how long it needs to be. I have some linen shoemaker's thread that is pretty strong stuff, I found it at an antique shop.
Which brings me to my question of the day, how do you make a string? I was just doubling the ends over and tying an overhand knot so the loop was about 5" long. I'll do a search but if anyone has tips or a link you can let me know.
Heres the update for this evening. Its mostly good news.
I managed to make a string that didn't break when I tried to string this bow. It is 14 strands of dacron, simply doubled over on each end and tied with an overhand knot to form the loops. I strung the bow using a stringer, that seemed to work pretty well. I needed the leverage, this thing is a bit of a beast.
I have posted a few more pics in the link above, one is the bow braced, one is the bow's side profile just after unstringing, and one is the bow partially drawn on a tiller stick. I don't have a tiller tree rigged up and nobody else was home to photograph as I pulled the bow.
As you can see I have one limb that is somewhat stronger than the other. I am seeking suggestions on how to even these up. I've scraped a bit on the horn on the stiff limb. I may also add another thin layer of sinew on the weaker limb. Although this remedy will increase the poundage a bit I suppose, not really what I am wanting. You can see in the just-unstrung pic, that the weaker limb is showing a bit more set than the strong limb. It seems fairly even, which is a good sign. I was worried that more of it was showing up on the outer end of the horn, where I butted a piece of wood to it to bolster the inner part of the siyah.
I measured the poundage on this bow with my bow scale. I managed to pull it all the way to 28" (back of handle) and measured close to 80lb. I shot a few arrows out of it but I can't pull it to full draw. Shot very strong and no hand shock but that is expected when pulling a bow only 20" or so.
I did see a few small cracks in one area of horn on the stronger limb. It is in the smaller of the two pieces spliced along that limb. It doesn't look very bad but I will keep and eye on it. The cracks run parallel to the limb, not across, so it doesn't look like compression fracture. Might just be the horn drying or something, that is the piece of horn from the outer third of the length and some of it was solid.
The weaker of the two limbs, needs to be wrapped out by the end of the horn. I got the piece of belly wood just outside the horn, just a little thin on that side. I want to shore it up, although I need to decide about adding sinew to the back before I do my wrap.
If you have read all of this boring narrative, congratulations you are officially bored stiff.
I managed to make a string that didn't break when I tried to string this bow. It is 14 strands of dacron, simply doubled over on each end and tied with an overhand knot to form the loops. I strung the bow using a stringer, that seemed to work pretty well. I needed the leverage, this thing is a bit of a beast.
I have posted a few more pics in the link above, one is the bow braced, one is the bow's side profile just after unstringing, and one is the bow partially drawn on a tiller stick. I don't have a tiller tree rigged up and nobody else was home to photograph as I pulled the bow.
As you can see I have one limb that is somewhat stronger than the other. I am seeking suggestions on how to even these up. I've scraped a bit on the horn on the stiff limb. I may also add another thin layer of sinew on the weaker limb. Although this remedy will increase the poundage a bit I suppose, not really what I am wanting. You can see in the just-unstrung pic, that the weaker limb is showing a bit more set than the strong limb. It seems fairly even, which is a good sign. I was worried that more of it was showing up on the outer end of the horn, where I butted a piece of wood to it to bolster the inner part of the siyah.
I measured the poundage on this bow with my bow scale. I managed to pull it all the way to 28" (back of handle) and measured close to 80lb. I shot a few arrows out of it but I can't pull it to full draw. Shot very strong and no hand shock but that is expected when pulling a bow only 20" or so.
I did see a few small cracks in one area of horn on the stronger limb. It is in the smaller of the two pieces spliced along that limb. It doesn't look very bad but I will keep and eye on it. The cracks run parallel to the limb, not across, so it doesn't look like compression fracture. Might just be the horn drying or something, that is the piece of horn from the outer third of the length and some of it was solid.
The weaker of the two limbs, needs to be wrapped out by the end of the horn. I got the piece of belly wood just outside the horn, just a little thin on that side. I want to shore it up, although I need to decide about adding sinew to the back before I do my wrap.
If you have read all of this boring narrative, congratulations you are officially bored stiff.
Some thoughts on reducing poundage to a manageable level. Feedback requested on this issue.
I'm not too sure that scraping horn will have much of an effect, and I need to keep a certain thickness to protect the core. Same for thinning sinew. As far as reducing limb width, I could maybe do a little of that. To get from 75-80lb, down to 65 (upper end of my comfort zone) I'd need to reduce width by 19%. I think the limbs are 1.25" wide, so I'd need to bring them down to 1" wide. I might get away with that without losing my lateral stability. I may also taper it in from full width at the handle and siyahs, so it bends a little harder at midlimb. That'll take some of the pressure off the ends of the horn that are butted up against wood spacers.
I also need to do a little work on my nocks ASAP. I cut them straight in, but the string rides on the inner side and very close to the top at brace. I'm going to cut them at more of an angle so the string sllides down in there better. Probably line that area of the nock with some horn too, this walnut is light enough that it might get cut into or split. I'll probably make another string with slightly longer loops, this one's loops rub on the sides of the siyahs.
As for finishing touches, I was thinking of covering it in silk and wrapping some areas with thread. I have to deal with the tiller and weight problems first of course.
Then its on to the next one, I still have the other two quarters of the gemsbok horn for another attempt and they are the better pieces. I figured I'd practice on the second rate material first. This time, I'll know to make the core more like 3/16" and maybe tapered a bit. Although, a lot of these bows bend hard early in the limb, so I don't know that a tapered core is the right thing to do. Will have to research that one a bit more.
I'm not too sure that scraping horn will have much of an effect, and I need to keep a certain thickness to protect the core. Same for thinning sinew. As far as reducing limb width, I could maybe do a little of that. To get from 75-80lb, down to 65 (upper end of my comfort zone) I'd need to reduce width by 19%. I think the limbs are 1.25" wide, so I'd need to bring them down to 1" wide. I might get away with that without losing my lateral stability. I may also taper it in from full width at the handle and siyahs, so it bends a little harder at midlimb. That'll take some of the pressure off the ends of the horn that are butted up against wood spacers.
I also need to do a little work on my nocks ASAP. I cut them straight in, but the string rides on the inner side and very close to the top at brace. I'm going to cut them at more of an angle so the string sllides down in there better. Probably line that area of the nock with some horn too, this walnut is light enough that it might get cut into or split. I'll probably make another string with slightly longer loops, this one's loops rub on the sides of the siyahs.
As for finishing touches, I was thinking of covering it in silk and wrapping some areas with thread. I have to deal with the tiller and weight problems first of course.
Then its on to the next one, I still have the other two quarters of the gemsbok horn for another attempt and they are the better pieces. I figured I'd practice on the second rate material first. This time, I'll know to make the core more like 3/16" and maybe tapered a bit. Although, a lot of these bows bend hard early in the limb, so I don't know that a tapered core is the right thing to do. Will have to research that one a bit more.
Enno put on more sinew to get higher weight, you say you are making core lighter.
If you remove the horn, how would it affect weight?
If you remove the horn, how would it affect weight?
Thinning horn will no doubt lower the poundage, but I think you need a certain amount of horn to protect the weaker core. So you can only safely thin so much.
See my next post, I was able to get the poundage right where I wanted it and describe how I went about it.
See my next post, I was able to get the poundage right where I wanted it and describe how I went about it.
More pics on the photobucket website, braced, full draw and just unbraced.
OK I finished watching the Korean hornbow video and learned a lot from the part where he tillered his bows. Basically I had not tillered mine, so it was good that it had the poundage it did. I bevelled the edges of the horn and thinned it a bit towards the middle, also brought down the width of the limbs just a bit. I made the thinner towards the handle, since you ewant more bend near the handle on these bows. I sanded the siyahs and cut the nocks in so there was more of a ledge for the string to ride in.
When I strung the bow I knew it had lost some poundage. I was able to string it using the step-through method. I measured the poundage and found it to be in the 60's, much more comfortable. Also, the tiller was much closer to where I wanted it, the limbs were more even and bending reasonably well. I still need to thin the midlimb on the upper limb a bit, it is bending a bit too hard at the handle in my opinion. I took it out and shot a few arrows out of it. This is a really nice bow to shoot. When first unstrung it showed equal set in each limb, another indication that it is properly balanced.
Now for the bad news. There is always bad news isn't there. I inspected the bow and found that the limb that was bending hard near the handle, had a little of the sinew lifting right in the beginning of the handle. Also, there was a small crack in the spacer wood on one edge, probably from the compression stress of getting mashed by the horn. I heated both areas and got some 2-ton epoxy in both cracks, and it is curing now.
Why did this happen? I think I was just being in too big of a hurry. I should have wrapped those areas with sinew as soon as I saw that the bow had a good tiller and poundage. Instead, I had to take it out and shoot it. Ah well, I can't help myself. Also, I will thin the horn a bit more at midlimb and take a little of the stress off that area.
In any case, I am getting close to finishing this sucker in what I feel is record time. I have to wrap the fades with either sinew or thread and glue, I need to cover the bow with silk and do some decorative thread wraps. I need to put a finish on the siyahs. And then I'm going to call it a bow.
OK I finished watching the Korean hornbow video and learned a lot from the part where he tillered his bows. Basically I had not tillered mine, so it was good that it had the poundage it did. I bevelled the edges of the horn and thinned it a bit towards the middle, also brought down the width of the limbs just a bit. I made the thinner towards the handle, since you ewant more bend near the handle on these bows. I sanded the siyahs and cut the nocks in so there was more of a ledge for the string to ride in.
When I strung the bow I knew it had lost some poundage. I was able to string it using the step-through method. I measured the poundage and found it to be in the 60's, much more comfortable. Also, the tiller was much closer to where I wanted it, the limbs were more even and bending reasonably well. I still need to thin the midlimb on the upper limb a bit, it is bending a bit too hard at the handle in my opinion. I took it out and shot a few arrows out of it. This is a really nice bow to shoot. When first unstrung it showed equal set in each limb, another indication that it is properly balanced.
Now for the bad news. There is always bad news isn't there. I inspected the bow and found that the limb that was bending hard near the handle, had a little of the sinew lifting right in the beginning of the handle. Also, there was a small crack in the spacer wood on one edge, probably from the compression stress of getting mashed by the horn. I heated both areas and got some 2-ton epoxy in both cracks, and it is curing now.
Why did this happen? I think I was just being in too big of a hurry. I should have wrapped those areas with sinew as soon as I saw that the bow had a good tiller and poundage. Instead, I had to take it out and shoot it. Ah well, I can't help myself. Also, I will thin the horn a bit more at midlimb and take a little of the stress off that area.
In any case, I am getting close to finishing this sucker in what I feel is record time. I have to wrap the fades with either sinew or thread and glue, I need to cover the bow with silk and do some decorative thread wraps. I need to put a finish on the siyahs. And then I'm going to call it a bow.
It looks nice and the weight is ok. You did just an ordinary tiller?
Can you shoot it trough a crono?
My guesse, 60# at 28" with 500 grain = 180 fps.
I put the handle on belly side so the sinew will not come of at the handle. I have seen that on others bows.
Can you shoot it trough a crono?
My guesse, 60# at 28" with 500 grain = 180 fps.
I put the handle on belly side so the sinew will not come of at the handle. I have seen that on others bows.
Now you tell me! That would certainly remove a potential pitfall, having the sinew run up a sharp angle is asking for trouble. I was just trying to use as much traditional design parameters as possible. Actually it held pretty well and I should have wrapped those areas right away. On my next one I'll do that.
Speaking of which, today I wrapped both the handle/fades and the inner siyah areas where the horn terminates, with sinew. There's a pic on the link above. Now for more waiting. When its dry, Ill cover the back with silk and put some finish on the siyahs.
I don't have a chrono but I am considering getting one just for fun. It would be nice if the bow had that sort of performance. It is certainly light, the walnut was not particularly dense and the horn and sinew are not real thick.
I kind of like how the grain is running on the walnut. I cut the siyahs out of a board rather than bending wood. This has the grain running parallel where the siyah is spliced to the core, and at an angle to the direction of the outer siyah. This offest means that the string is not pushing straight into the grain at the nock. I've had nocks split in the past, and I think the angle of the grain will help to prevent this.
Speaking of which, today I wrapped both the handle/fades and the inner siyah areas where the horn terminates, with sinew. There's a pic on the link above. Now for more waiting. When its dry, Ill cover the back with silk and put some finish on the siyahs.
I don't have a chrono but I am considering getting one just for fun. It would be nice if the bow had that sort of performance. It is certainly light, the walnut was not particularly dense and the horn and sinew are not real thick.
I kind of like how the grain is running on the walnut. I cut the siyahs out of a board rather than bending wood. This has the grain running parallel where the siyah is spliced to the core, and at an angle to the direction of the outer siyah. This offest means that the string is not pushing straight into the grain at the nock. I've had nocks split in the past, and I think the angle of the grain will help to prevent this.
Lennie:
Congratulations. Quick and well done.
It seems to me though, the tips are much too heavy for this bow. If I were you, I'd reduce the tips to taper at the nocks, then, if you are worried about the splits along the grain, you can use a few strands of sinew to wrap below the nocks. To give you an example of small tips: Turkish bows of some 100lb had tips only 10-12mm x 15-18mm. Also the horn can be thinned at the siyahs to almost nothing for better performance.
And I would let the bow bend a bit farther from the grip too. People are paranoid about stacking these days, but a good hornbow should stack for the last 1-2 inches (this may not be felt anyway - only shows on the f-d curve).
Adam
Congratulations. Quick and well done.
It seems to me though, the tips are much too heavy for this bow. If I were you, I'd reduce the tips to taper at the nocks, then, if you are worried about the splits along the grain, you can use a few strands of sinew to wrap below the nocks. To give you an example of small tips: Turkish bows of some 100lb had tips only 10-12mm x 15-18mm. Also the horn can be thinned at the siyahs to almost nothing for better performance.
And I would let the bow bend a bit farther from the grip too. People are paranoid about stacking these days, but a good hornbow should stack for the last 1-2 inches (this may not be felt anyway - only shows on the f-d curve).
Adam
Thanks for the advice. The walnut used for these siyahs is not very dense, I chose it for this reason. But I was looking at them and wondering if I could reduce the mass, certainly everything outside the nocks (1") is fair game. I tapered the siyahs some from back to belly to give them a bit of a triangular cross section, thought this would reduce mass while maintining stiffness. The bow does not shock the hand, which is some indication that mass is not that excessive. I suppose I could cut new nocks and shorten them somewhat, this would reduce my net reflex. Currently the bow only shows around 4", I'd lose almost nother inch if I wer to cut the nocks an inch closer. Now that poundage is manageable, I suppose I could go this route. It would certainly buy me more room to tiller.
This bow is definitely not going to stack, I'm not getting close to a 90 degree string angle. Looks like maybe 75 degrees at my 27" draw. I'll take a closer look at the full drawn profile to see where I can tweak tiller. Of course, with the sinew being less than a month dry, I think the tiller might continue to change for some time. Its close now, that is all I was after. And I know how to tiller it now, thanks to Duvernay's video.
In looking more closely at various of the genuine artifacts, I realize that I made these siyahs inordinately large. I guess this was what was in my mind's eye more than anything. The siyahs are the feature that stands out, and this bow proves it! I'll certainly be making future bows more in line with established designs and methods.
This bow is definitely not going to stack, I'm not getting close to a 90 degree string angle. Looks like maybe 75 degrees at my 27" draw. I'll take a closer look at the full drawn profile to see where I can tweak tiller. Of course, with the sinew being less than a month dry, I think the tiller might continue to change for some time. Its close now, that is all I was after. And I know how to tiller it now, thanks to Duvernay's video.
In looking more closely at various of the genuine artifacts, I realize that I made these siyahs inordinately large. I guess this was what was in my mind's eye more than anything. The siyahs are the feature that stands out, and this bow proves it! I'll certainly be making future bows more in line with established designs and methods.
http://s96.photobucket.com/albums/l200/ ... ite%20Bow/
The last three pics added, are showing the silk that I glued over the sinew and painted black, the cord handle wrap, and another full draw pic. I still have to finish the siyahs, paint something more lively on the black back, and possibly add a leather grip. The cord wrap, I did just like I was serving a string. It worked great, covered the sinew wrap of the handle/fades and looks sharp.
The last three pics added, are showing the silk that I glued over the sinew and painted black, the cord handle wrap, and another full draw pic. I still have to finish the siyahs, paint something more lively on the black back, and possibly add a leather grip. The cord wrap, I did just like I was serving a string. It worked great, covered the sinew wrap of the handle/fades and looks sharp.