Magyar Bow
Hi all.
This is my first post at ATARN. I have quite recently become interested in bow making and have made several self-bows out of osage that turned out fairly well. I am now interested in trying my hand at making an asian composite bow and have decided to make something along the lines of a generalized version of a Magyar bow (if for no other reason than that I'm part Hungarian).
I have been following the ATARN forums for quite some time now and have been trying to absorb all the wonderful information out there. I have also gotten Adam Karpowicz's excellent book on the Ottoman Turkish bow, which appears to be THE bible on making traditional composite bows, and am studying that.
While I have not yet acquired any horn or sinew, I have more or less completed the core section, and this is where I need to clarify a number of things before I go much further.
The core is a flat piece of very straight-grained hard maple 43.5 inches (1100 mm) long, with the ends steam-bent upward slightly to smoothly fit the siyahs, which are made out curved-grain osage, and are about 8.5 inches (215 mm) long, and meet the bending section at a 40-degree angle. The siyahs are V-spliced into the bending section. The nock-to-nock distance in the unreflexed, unbraced state is about 54 inches (1370 mm). (I'm sure it's considered sacrilege by the purists out there, but I used white carpenter's glue to fasten the siyahs, simply because I am used to working with the stuff and don't have any hide glue at the moment.
At this point the core is about 33 mm wide and 5 mm thick.
Now here's where I need some advise.
1) I've observed that the core for Turkish and Korean bows have a tremendous amount of relfex built in, even before attaching horn and sinew. In most of these, the plane of the tips are at even more than right angles with the bending section, whereas my Magyar bow right now is only at 40 degrees. So my question is: do I need to add some reflex to this continuous straight section of core before I attach horn and sinew, or will the shrinkage of the sinew itself take care of that? Most Magyar and Mongol bows I've see pictures of don't appear to have nearly as much reflex as the Turkish and Korean bows. I realize that lots of reflex is needed to make use of the elastic properties of the sinew, but to be frank, all that bending really scares me.
2) If one is not set on historical faithfulness, can white carpenter's glue (such as Titebond III in the US) be used to attach the horn? Does anyone out there have any experience with doing that? It strikes me that enough things can go wrong at all steps in making one of these things that I'd like to avoid the vagaries of dealing with heated hide glue, at least for this step. (I strongly suspect that carpenter's glue cannot be used for the sinew, but that's fine with me).
Well, I've got a lot more questions, but I've taken up enough space. Thanks in advance for your replies.
This is my first post at ATARN. I have quite recently become interested in bow making and have made several self-bows out of osage that turned out fairly well. I am now interested in trying my hand at making an asian composite bow and have decided to make something along the lines of a generalized version of a Magyar bow (if for no other reason than that I'm part Hungarian).
I have been following the ATARN forums for quite some time now and have been trying to absorb all the wonderful information out there. I have also gotten Adam Karpowicz's excellent book on the Ottoman Turkish bow, which appears to be THE bible on making traditional composite bows, and am studying that.
While I have not yet acquired any horn or sinew, I have more or less completed the core section, and this is where I need to clarify a number of things before I go much further.
The core is a flat piece of very straight-grained hard maple 43.5 inches (1100 mm) long, with the ends steam-bent upward slightly to smoothly fit the siyahs, which are made out curved-grain osage, and are about 8.5 inches (215 mm) long, and meet the bending section at a 40-degree angle. The siyahs are V-spliced into the bending section. The nock-to-nock distance in the unreflexed, unbraced state is about 54 inches (1370 mm). (I'm sure it's considered sacrilege by the purists out there, but I used white carpenter's glue to fasten the siyahs, simply because I am used to working with the stuff and don't have any hide glue at the moment.
At this point the core is about 33 mm wide and 5 mm thick.
Now here's where I need some advise.
1) I've observed that the core for Turkish and Korean bows have a tremendous amount of relfex built in, even before attaching horn and sinew. In most of these, the plane of the tips are at even more than right angles with the bending section, whereas my Magyar bow right now is only at 40 degrees. So my question is: do I need to add some reflex to this continuous straight section of core before I attach horn and sinew, or will the shrinkage of the sinew itself take care of that? Most Magyar and Mongol bows I've see pictures of don't appear to have nearly as much reflex as the Turkish and Korean bows. I realize that lots of reflex is needed to make use of the elastic properties of the sinew, but to be frank, all that bending really scares me.
2) If one is not set on historical faithfulness, can white carpenter's glue (such as Titebond III in the US) be used to attach the horn? Does anyone out there have any experience with doing that? It strikes me that enough things can go wrong at all steps in making one of these things that I'd like to avoid the vagaries of dealing with heated hide glue, at least for this step. (I strongly suspect that carpenter's glue cannot be used for the sinew, but that's fine with me).
Well, I've got a lot more questions, but I've taken up enough space. Thanks in advance for your replies.
Titebond isn't what I'd call "white carpenter glue" -- that would be that Elmer's nonsense, Titebond II would be better than III. I understand there have been 'slippage' issue with III. I have built two-wood composite bows with siyahs using Titebond and Titebond II with good success
I'm not enamored of the idea of keeping a glue pot warm either. However, Titebond now makes a Liquid Hide Glue that I'm going to try on the all-wood Scythian I'm working on. I picked mine up Ace Hardware. My local Big Box stores do not carry it.
I'm not enamored of the idea of keeping a glue pot warm either. However, Titebond now makes a Liquid Hide Glue that I'm going to try on the all-wood Scythian I'm working on. I picked mine up Ace Hardware. My local Big Box stores do not carry it.
Hello Edmund,
In my first bow project, I used a modern 'white carpenter glue' PVA (polyvinlyacetate I believe) to glue the wooden parts of the core together, including a lamination between the non-bending ear and the bending limb.
I then used hide glue for horn and sinew components.
Everything was fine until the 3rd layer of sinew. As the sinew dried and curled the bow up, it ripped the PVA glued laminations apart, so that there was a ~ 5 mm gap. I was not intending to curl the bow up like one of the pretzel shaped flight bows, and so did not put it in any former to encourage the C- shape. The bow simply ripped itself apart.
I have made two more bows since, using hide glue and materials that you can glue with hide glue (seemly exclusively natural materials), and I have not had a repeat of this problem. Hide glue seems to be both stronger and more flexible than modern glues, under the right conditions.
Of course, it could have been my own shoddy work that caused my catastrophe, however, I strongly suspect that hide glue is superior for this application.
I heartily recommend you get some hide glue, and try glueing some test joints together. The experience of using hide glue with wood will prepare you for the glue intensive tasks of sinewing and glueing the horn. I have never attempted to glue sinew or horn without using hide glue. It is not difficult to use (without any training or direction I managed to glue up a test joint first time).
Best of Luck
In my first bow project, I used a modern 'white carpenter glue' PVA (polyvinlyacetate I believe) to glue the wooden parts of the core together, including a lamination between the non-bending ear and the bending limb.
I then used hide glue for horn and sinew components.
Everything was fine until the 3rd layer of sinew. As the sinew dried and curled the bow up, it ripped the PVA glued laminations apart, so that there was a ~ 5 mm gap. I was not intending to curl the bow up like one of the pretzel shaped flight bows, and so did not put it in any former to encourage the C- shape. The bow simply ripped itself apart.
I have made two more bows since, using hide glue and materials that you can glue with hide glue (seemly exclusively natural materials), and I have not had a repeat of this problem. Hide glue seems to be both stronger and more flexible than modern glues, under the right conditions.
Of course, it could have been my own shoddy work that caused my catastrophe, however, I strongly suspect that hide glue is superior for this application.
I heartily recommend you get some hide glue, and try glueing some test joints together. The experience of using hide glue with wood will prepare you for the glue intensive tasks of sinewing and glueing the horn. I have never attempted to glue sinew or horn without using hide glue. It is not difficult to use (without any training or direction I managed to glue up a test joint first time).
Best of Luck
M Hardman,
Thanks for the input.
I am now convinced that there is probably no good way of getting around learning how to use hide glue effectively. Even though it's much more tricky to use than carpenter's glue, its been well proven through centuries of experience, and I'd probably be introducing more uncertainty by trying carpenter's glue for the horn.
I'll just have to get some hide glue and do a little practicing. I'd probably have to use it for the sinew anyway.
Thanks for the input.
I am now convinced that there is probably no good way of getting around learning how to use hide glue effectively. Even though it's much more tricky to use than carpenter's glue, its been well proven through centuries of experience, and I'd probably be introducing more uncertainty by trying carpenter's glue for the horn.
I'll just have to get some hide glue and do a little practicing. I'd probably have to use it for the sinew anyway.
Do a search on stickbow.com (leatherwall). Seems I remember a lively discussion on using titebond III for glueing sinew. Some said don't do it others said it works fine plus the glue is waterproof.
http://leatherwall.bowsite.com/TF/lw/th ... 88#3345838
Todd
http://leatherwall.bowsite.com/TF/lw/th ... 88#3345838
Todd
The lack of extreme reflex in modern Mongolian and Hungarian bows comes from two different sources. In the case of the Mongolian bows, high quality animal glues were difficult to acquire and bows were made less stressed for safety. Mongolian bowyers are now getting access to better quality glues and developing better methods of making them so I imagine they will start experimenting with bows with a higher reflex. The Hungarian experience is slightly different since they were originally working with archaeological models and buried bows probably were old and opened out when they were put in a grave. Since the Hungarians, with Fabian, started making composite bows before much of the modern research was available, they were pioneering the techniques that are now better known. In both cases, the bows work and were suitable for the uses they were needed for. However, in both countries, the bowyers are experimenting and increasing in skill.
Adam's book gives good reasons for increasing reflex for bedding the sinew down as it dries. The different techniques used in Korea provide an alternate method, but it starts with a higher reflex. Because of the density of horn and sinew, if you do not highly stress it, you may as well make an all wood bow because you will not get the performance out of an under-stressed horn, wood, sinew composite.
Regarding the animal glue, its match in qualities make it ideal when used with horn and sinew. Since many bows will need heat treatment in their lifetimes, it is best to use compatible materials. some old books and more recent information suggesting liquid hide glue might not be the best substitute. My own experience is that for quite a long time after setting it can re-liquefy in high ambient temperatures. I had a set of feathers curl and fall off for that reason in Utah one flight shoot. The stress on them was only the natural curve of the the feather vanes trying to reassert itself. I hate to think what would have happened with horn and sinew in a highly stressed bow.
Adam's book gives good reasons for increasing reflex for bedding the sinew down as it dries. The different techniques used in Korea provide an alternate method, but it starts with a higher reflex. Because of the density of horn and sinew, if you do not highly stress it, you may as well make an all wood bow because you will not get the performance out of an under-stressed horn, wood, sinew composite.
Regarding the animal glue, its match in qualities make it ideal when used with horn and sinew. Since many bows will need heat treatment in their lifetimes, it is best to use compatible materials. some old books and more recent information suggesting liquid hide glue might not be the best substitute. My own experience is that for quite a long time after setting it can re-liquefy in high ambient temperatures. I had a set of feathers curl and fall off for that reason in Utah one flight shoot. The stress on them was only the natural curve of the the feather vanes trying to reassert itself. I hate to think what would have happened with horn and sinew in a highly stressed bow.
Thanks for that warning about Liquid Hide Glue, Bede.
Yesterday I started gluing up the 2 and 3 pieces of 1/8" thick Red Elm to make one full length lam for the all-wood Scythian I'm attempting. Ambient temperatures on the Gulf Coast of Florida are mid to high 80s F, with humidity also in the 80% range. According to the manufacturer, the liquid hide glue was supposed to be 'clamp free' after 30 minutes with no stress to be applied on the joint for 24 hours. I was finding that after an hour the glue was still tacky, although test joints did not slip under sideways pressure. The glue-up I left overnight (8 full hours) last night was perfectly dry (at least to touch) this morning.
From your article about the bows at Xinjiang, Bede, I'm using the three layer oval cross-section of the bow from the Three Brothers Kurgan. However, mine will be made up of 3 Osage Orange lams in the center between 3 lams of Red Elm on the back and 3 on the belly.
I may switch to Titebond when it comes to gluing together the 9 full-length lams that will form the basis for the bow. That decision is still out for comment...
Yesterday I started gluing up the 2 and 3 pieces of 1/8" thick Red Elm to make one full length lam for the all-wood Scythian I'm attempting. Ambient temperatures on the Gulf Coast of Florida are mid to high 80s F, with humidity also in the 80% range. According to the manufacturer, the liquid hide glue was supposed to be 'clamp free' after 30 minutes with no stress to be applied on the joint for 24 hours. I was finding that after an hour the glue was still tacky, although test joints did not slip under sideways pressure. The glue-up I left overnight (8 full hours) last night was perfectly dry (at least to touch) this morning.
From your article about the bows at Xinjiang, Bede, I'm using the three layer oval cross-section of the bow from the Three Brothers Kurgan. However, mine will be made up of 3 Osage Orange lams in the center between 3 lams of Red Elm on the back and 3 on the belly.
I may switch to Titebond when it comes to gluing together the 9 full-length lams that will form the basis for the bow. That decision is still out for comment...
Bede,
Thanks for the information and perspective. Very interesting.
I can appreciate the need for lots of reflex in order to fully derive the benefit of the high elasticity of the sinew. However, with regard to the Magyar bow I am trying to build, I currently have a straight continuous piece of maple for the core. So, I have two questions I need to answer before I go any further:
1) Is it advisable to attach the horn (using hide glue, as I am now convinced I need to use) to a straight unreflexed bending limb, or should that limb be forced into a certain amount of reflex prior to the horning step?
2) If the horn is attached to the bending limb in an unreflexed state, will the shrinkage of the sinew during the sinewing step by itself be sufficient to induce enough relex, or should the tips of the siyahs be progressively pulled closer together during the application of the several layers of sinew? If so, how much is enough? Too much?
Right now the siyahs lie at about a 40-degree angle to the line of the straight core section. Is there any way of knowing how much that angle is going to increase after sinewing, or is that a hit-or-miss type of thing only learned through trial and error?
Thanks for the information and perspective. Very interesting.
I can appreciate the need for lots of reflex in order to fully derive the benefit of the high elasticity of the sinew. However, with regard to the Magyar bow I am trying to build, I currently have a straight continuous piece of maple for the core. So, I have two questions I need to answer before I go any further:
1) Is it advisable to attach the horn (using hide glue, as I am now convinced I need to use) to a straight unreflexed bending limb, or should that limb be forced into a certain amount of reflex prior to the horning step?
2) If the horn is attached to the bending limb in an unreflexed state, will the shrinkage of the sinew during the sinewing step by itself be sufficient to induce enough relex, or should the tips of the siyahs be progressively pulled closer together during the application of the several layers of sinew? If so, how much is enough? Too much?
Right now the siyahs lie at about a 40-degree angle to the line of the straight core section. Is there any way of knowing how much that angle is going to increase after sinewing, or is that a hit-or-miss type of thing only learned through trial and error?
I am not advising you as a bowyer, but as a researcher. There are many good bowyers on this forum and their advices is to be preferred.
1) Adam Karpowicz in his book did not suggest that the bow should be greatly reflexed before the horn was added and even commented that a thin core could allow the horn (because is its already curved in most cases) to induce an unnecessary amount of reflex before the sinew is added. The Koreans also start out with a fairly thick core to attach the horn.
2) Comparing Adam's comments to discussions I have had with McEwen and David Betteridge, it seems that adding reflex might be more important to help hold the sinew against the core that anything else. This removes the need to bind the sinew while the glue dries. I recommend Adam's discussion of this in his book on Ottoman bows. This by far the best published analysis of this subject I have seen.
Other people have used other methods with varying degrees of success. I have shot composite bows by Betteridge, Karpowicz, Koppedrayer and McEwen. They all performed well, considering what each was designed for. I have only shot one old bow, a Manchu bow of the early nineteenth century. All these bows had a smoothness of action that is much rarer in modern materials bows. The variations in the means of construction still produced good bows. I am sure there is no one answer.
1) Adam Karpowicz in his book did not suggest that the bow should be greatly reflexed before the horn was added and even commented that a thin core could allow the horn (because is its already curved in most cases) to induce an unnecessary amount of reflex before the sinew is added. The Koreans also start out with a fairly thick core to attach the horn.
2) Comparing Adam's comments to discussions I have had with McEwen and David Betteridge, it seems that adding reflex might be more important to help hold the sinew against the core that anything else. This removes the need to bind the sinew while the glue dries. I recommend Adam's discussion of this in his book on Ottoman bows. This by far the best published analysis of this subject I have seen.
Other people have used other methods with varying degrees of success. I have shot composite bows by Betteridge, Karpowicz, Koppedrayer and McEwen. They all performed well, considering what each was designed for. I have only shot one old bow, a Manchu bow of the early nineteenth century. All these bows had a smoothness of action that is much rarer in modern materials bows. The variations in the means of construction still produced good bows. I am sure there is no one answer.
Bede,
Thanks again. I do have Adam's book, and it is excellent, the Bible on composite bow making.
However, his book deals almost exclusively with the Turkish style bow, which has a huge amount of reflex already built into the shape of the core/kasan/tip configuration. So, while I know he doesn't recommend putting more reflex into the core while applying horn and sinew, I was wondering whether that was because it already had enough due to the shape.
It would really not be very difficult to add a little reflex to the straight core by either i) steam bending the center of the core, or ii) cutting the core in the middle and then reattaching the two pieces at an angle to a center grip section with V joints. The question is whether I need to do this or should to this.
Anyway, I've got lots of time to think about this, as I have not yet acquired any horn or sinew.
Thanks again. I do have Adam's book, and it is excellent, the Bible on composite bow making.
However, his book deals almost exclusively with the Turkish style bow, which has a huge amount of reflex already built into the shape of the core/kasan/tip configuration. So, while I know he doesn't recommend putting more reflex into the core while applying horn and sinew, I was wondering whether that was because it already had enough due to the shape.
It would really not be very difficult to add a little reflex to the straight core by either i) steam bending the center of the core, or ii) cutting the core in the middle and then reattaching the two pieces at an angle to a center grip section with V joints. The question is whether I need to do this or should to this.
Anyway, I've got lots of time to think about this, as I have not yet acquired any horn or sinew.
Hi
There is a discussion of Magyar bows here:
http://atarn.net/phpBB2/viewtopic.php?t ... an&start=0
If you go to the second page, about halfway down in a post by Andrew Hall you will find plans you can download for the Moshcheveya Balka bow. Not vey unlike magyar.
Hide glue can be used quite easily. Soak first for several hours (or best overnight) in cold water. (cold is important) Then I put the gluepot in a water bath with hot water from the tap. The glue will then dissolve easily. If you work for so long that the glue thickens, put fresh hot water in the bath.
Best of all: When finished rinse your hands in lukewarm water. Try that with epoxy!
There is a discussion of Magyar bows here:
http://atarn.net/phpBB2/viewtopic.php?t ... an&start=0
If you go to the second page, about halfway down in a post by Andrew Hall you will find plans you can download for the Moshcheveya Balka bow. Not vey unlike magyar.
Hide glue can be used quite easily. Soak first for several hours (or best overnight) in cold water. (cold is important) Then I put the gluepot in a water bath with hot water from the tap. The glue will then dissolve easily. If you work for so long that the glue thickens, put fresh hot water in the bath.
Best of all: When finished rinse your hands in lukewarm water. Try that with epoxy!
Edmund,
Just one correction: there is a difference between putting in extra reflex in with both horn and sinew and one or the other individually. Adding reflex while adding the sinew is what I was talking about. This means the horn doesn't dominate the shape of the core. However, whatever choice you make will be a valuable experiment in studying these bows. The possibilities have not been exhausted yet. Good luck.
Just one correction: there is a difference between putting in extra reflex in with both horn and sinew and one or the other individually. Adding reflex while adding the sinew is what I was talking about. This means the horn doesn't dominate the shape of the core. However, whatever choice you make will be a valuable experiment in studying these bows. The possibilities have not been exhausted yet. Good luck.
I would suggest let the limb straight on the first several bows. However you should add a sharp reflex (angle 170-160 degree) at the middle of the handle. The tips of the bow should be pulled together during sinewing, but sinew alone will not do that. You should use additional force. The core has not the right dimension. It should be 40mm wide and 10mm thick. This thickness is necessary to prepare the proper thinning of the core. The core also seems to be to long. (90-105). The ears should be about 22-25 with the string nocks at 17-20cm. 40 degree for the ears may be to much. You can end up with a bow with which needs string bridges (not Hungarian) 30-35 is enough but it depends on the shape of limbs of the braced bow.
Yes, reflex in the bending section can lead to danger of the layers coming apart as the limb is flexed. This should not be confused with adding reflex to the bending section by pulling the tips together as the sinew dries. These two are altogether different. I sort of "invented" the latter to add a measure of safety and prevent any chances of sinew pulling up. The Turkish technique can be interpreted to serve the same purpose and it does not cause any undue strain later on.
The built-in reflex in the bending section, made by gluing the horn and core in this position can be tried to enhance the performance, but I would advise not to exceed 30cm radius in this section. Again, I want to be clear that each section of bow must be considered separately. I am talking about the bending section alone, not about the grip reflex, kasan or tips. One can go to extremes in the other sections and still be safe, as long as the bending section is not curved too much. It can be tried as an experiment, but I would suggest to reduce the core thickness by gluing thicker horn and sinew, which will de-stress the glue lines, reduce the overall thickness of the limb and make the bending sections long (Korean bows are a good example of that).
Adam
The built-in reflex in the bending section, made by gluing the horn and core in this position can be tried to enhance the performance, but I would advise not to exceed 30cm radius in this section. Again, I want to be clear that each section of bow must be considered separately. I am talking about the bending section alone, not about the grip reflex, kasan or tips. One can go to extremes in the other sections and still be safe, as long as the bending section is not curved too much. It can be tried as an experiment, but I would suggest to reduce the core thickness by gluing thicker horn and sinew, which will de-stress the glue lines, reduce the overall thickness of the limb and make the bending sections long (Korean bows are a good example of that).
Adam
Adam has the point. Almost all of my bows were made with straight limbs.
Adam and Paku,
Thanks much for the info and advice.
I will certainly heed this advice and not add any curvature to the bending section prior to attaching horn and sinew. I can now see why that would add difficulties.
I see that a number of the design diagrams for the Magyar bow indicate a 30-degree angle between the siyah and the bending section plus the flat bending section making a 10-to-20 degree forward angle with the grip section. As such, the total angle the nock makes with the horizontal plane (with the bow lying flat) would be 40 to 50 degrees.
Because I had not initially planned on angling the bending section at the grip, as appears to be done with some Magyar bows, I thought that I'd make up for it a little by having a 40-degree siyah angle. If I do need a bridge, I can always add one, but as Paku rightly points out, it would no longer strictly be a Magyar bow.
I know that my nock-to-nock distance of 135 cm is around 10 cm longer than what is indicated for a typical Magyar bow, but I deliberately made the core a little longer, as I was being cautious and wanted to increase the radius of curvature a bit. I can always cut the core, take out a section, and then splice it back together. But perhaps I can make up for the reduced stiffness by going a little heavier with the sinew. (?)
Thanks again.
Thanks much for the info and advice.
I will certainly heed this advice and not add any curvature to the bending section prior to attaching horn and sinew. I can now see why that would add difficulties.
I see that a number of the design diagrams for the Magyar bow indicate a 30-degree angle between the siyah and the bending section plus the flat bending section making a 10-to-20 degree forward angle with the grip section. As such, the total angle the nock makes with the horizontal plane (with the bow lying flat) would be 40 to 50 degrees.
Because I had not initially planned on angling the bending section at the grip, as appears to be done with some Magyar bows, I thought that I'd make up for it a little by having a 40-degree siyah angle. If I do need a bridge, I can always add one, but as Paku rightly points out, it would no longer strictly be a Magyar bow.
I know that my nock-to-nock distance of 135 cm is around 10 cm longer than what is indicated for a typical Magyar bow, but I deliberately made the core a little longer, as I was being cautious and wanted to increase the radius of curvature a bit. I can always cut the core, take out a section, and then splice it back together. But perhaps I can make up for the reduced stiffness by going a little heavier with the sinew. (?)
Thanks again.
For a 28 inch draw length the best is 130cm overall length (90+2x20) Even a 10 cm longer bow will have a considerable hand shock and reduced cast.
Paku,
So, if my core is 110 cm long in its unreflexed and unbraced state, do you think it advisable for me to shorten it up to somewhere within the 90 -105 cm range that you mentioned? If so, what length would you use if it were your bow? Right now the nock-to-nock distance is about 135 cm. Should I bring that down to a little less than 125 cm?
Mind you, I am not going for a really heavy bow, and something at around 60 lbs would be more than enough for someone my age and size. (My comfortable draw is only 26 inches anyway.)
I could just cut the core at the midpoint, remove the required amount, and then reattach the two limbs with a V-splice. (Or maybe just overlap one limb onto the other, as I've seen in some pictures. Though wouldn't a V-splice be better?)
While I have the core in two pieces, do you think that while I'm at it, I should angle each limb outward to about 10 degree before I rejoin them? As I already have the siyahs at 40 degrees, the additional 10 degrees would bring me up to 50 degees. Or would it be better to just leave the limbs at the current straight 180 degrees, i.e., zero outward angle?
I really appreciate this advice, as it will help me get it right the first time.
So, if my core is 110 cm long in its unreflexed and unbraced state, do you think it advisable for me to shorten it up to somewhere within the 90 -105 cm range that you mentioned? If so, what length would you use if it were your bow? Right now the nock-to-nock distance is about 135 cm. Should I bring that down to a little less than 125 cm?
Mind you, I am not going for a really heavy bow, and something at around 60 lbs would be more than enough for someone my age and size. (My comfortable draw is only 26 inches anyway.)
I could just cut the core at the midpoint, remove the required amount, and then reattach the two limbs with a V-splice. (Or maybe just overlap one limb onto the other, as I've seen in some pictures. Though wouldn't a V-splice be better?)
While I have the core in two pieces, do you think that while I'm at it, I should angle each limb outward to about 10 degree before I rejoin them? As I already have the siyahs at 40 degrees, the additional 10 degrees would bring me up to 50 degees. Or would it be better to just leave the limbs at the current straight 180 degrees, i.e., zero outward angle?
I really appreciate this advice, as it will help me get it right the first time.
As it is your first bow I would let the core as it is. It would be very difficult to cut it in the middle reflex and rejoin it as you have already attached the ears. The 135 cm ntn is OK.
The main problem will be the 5mm thickness of the core. You will have a bow (if everything goes well) which will bend mostly close to the handle. I just can cite Adam?s formulation ?the core and the horn have to have an exponential decay? (from the middle of the handle) . This may be an elusive definition but it works perfectly. However thid can not be achieved by 5mm overall thickness of the core.
The main problem will be the 5mm thickness of the core. You will have a bow (if everything goes well) which will bend mostly close to the handle. I just can cite Adam?s formulation ?the core and the horn have to have an exponential decay? (from the middle of the handle) . This may be an elusive definition but it works perfectly. However thid can not be achieved by 5mm overall thickness of the core.
Paku,
It really wouldn't be all that difficult for me to remove 10 cm and splice the core back together if a 125 cm nock-to-nock distance would be an improvement over my original 135 dimension. I want to do this right.
Just to make sure we're talking about the same thing, when I say that my core is 5 mm thick, I am referring only to the bare wood, not the overall thickness of the completed bending section. So, if I have a 5 mm wooden core, a 4 mm layer of horn, and say a 2 or 3 mm layer of sinew, I would have a limb thickness of 11 to 12 mm, which seems to be typical for a moderate weight bow. Or am I missing something here?
Now I am well aware of how sensitive stiffness is to thickness (varies as the cube), but from what I've seen of these composite bows, there usually isn't much taper in width across the bending section, but there is usually some thinning of the horn as one goes from the grip section to the ears. I assume this is where most of the variation in stiffness comes from. In the Magyar bow, is there typically also much thinning of the wooden core itself as one goes from grip to ear? If so, what should that thickness variation be for a moderate weight bow?
It really wouldn't be all that difficult for me to remove 10 cm and splice the core back together if a 125 cm nock-to-nock distance would be an improvement over my original 135 dimension. I want to do this right.
Just to make sure we're talking about the same thing, when I say that my core is 5 mm thick, I am referring only to the bare wood, not the overall thickness of the completed bending section. So, if I have a 5 mm wooden core, a 4 mm layer of horn, and say a 2 or 3 mm layer of sinew, I would have a limb thickness of 11 to 12 mm, which seems to be typical for a moderate weight bow. Or am I missing something here?
Now I am well aware of how sensitive stiffness is to thickness (varies as the cube), but from what I've seen of these composite bows, there usually isn't much taper in width across the bending section, but there is usually some thinning of the horn as one goes from the grip section to the ears. I assume this is where most of the variation in stiffness comes from. In the Magyar bow, is there typically also much thinning of the wooden core itself as one goes from grip to ear? If so, what should that thickness variation be for a moderate weight bow?
Paku, Adam, et al,
I have digested your advice and other's and thus decided to salvage the ears and start over again with a new core for my Magyar style bow (I say 'style' because I am not trying to faithfully reproduce it with historical accuracy).
I am at a stage now where the maple core is nearing completion, and I am a bit hesitant to shape it any further or to remove any more material until the horn is attached (which I have not yet acquired).
Here are some of the particulars:
- Unbraced nock-to-nock distance of the bare core - 122 cm
- Angle that each ear makes with the core - 10 degree slanting forward
- Distance from nock along the ear to the core - 20.3 cm
- Length of active part of bending limb - approx. 30 - 31 cm
- Width of bending limb - tapers from 40 mm down to about 32 mm
- Thickness of bending limb - approx 9 mm near grip and 7 - 8 mm near ear splice.
- The core has a VERY slight convexity on both side.
- Desired final draw weight - no more than 60 lbs at my short 26-inch draw.
So my question right now is: should I do any more shaping and material removal or should this wait till after the horn is in place?
Second question: I know that estimating the final weight of the bow is a very tricky and uncertain thing with composite bows, but if the horn and core thickness should be about the same and the sinew thickness much less, roughly what should the final core thickness be for a bow in the 60 lb range? Any advice of whether I need more or less width and thickness taper in the core?
Thanks in advance
I have digested your advice and other's and thus decided to salvage the ears and start over again with a new core for my Magyar style bow (I say 'style' because I am not trying to faithfully reproduce it with historical accuracy).
I am at a stage now where the maple core is nearing completion, and I am a bit hesitant to shape it any further or to remove any more material until the horn is attached (which I have not yet acquired).
Here are some of the particulars:
- Unbraced nock-to-nock distance of the bare core - 122 cm
- Angle that each ear makes with the core - 10 degree slanting forward
- Distance from nock along the ear to the core - 20.3 cm
- Length of active part of bending limb - approx. 30 - 31 cm
- Width of bending limb - tapers from 40 mm down to about 32 mm
- Thickness of bending limb - approx 9 mm near grip and 7 - 8 mm near ear splice.
- The core has a VERY slight convexity on both side.
- Desired final draw weight - no more than 60 lbs at my short 26-inch draw.
So my question right now is: should I do any more shaping and material removal or should this wait till after the horn is in place?
Second question: I know that estimating the final weight of the bow is a very tricky and uncertain thing with composite bows, but if the horn and core thickness should be about the same and the sinew thickness much less, roughly what should the final core thickness be for a bow in the 60 lb range? Any advice of whether I need more or less width and thickness taper in the core?
Thanks in advance
Do not touch the core now. For a 60lb bow 4-4-4mm is enough.
Paku,
Thanks.
I won't continue with any wood removal until I get the horn properly attached to the core. I will also try to get close to having the thickness of sinew, wood, and horn to be about the same.
I noticed that you did not mention any thickness tapering of the wood core, so should I assume one should keep the core in the bending section of the limb at uniform thickness from the fade at the grip to the fade at the ears?
(I just want to be sure, because I can't do anything about the core once it's locked between sinew and horn, except for making minor reductions in width.)
Thanks.
I won't continue with any wood removal until I get the horn properly attached to the core. I will also try to get close to having the thickness of sinew, wood, and horn to be about the same.
I noticed that you did not mention any thickness tapering of the wood core, so should I assume one should keep the core in the bending section of the limb at uniform thickness from the fade at the grip to the fade at the ears?
(I just want to be sure, because I can't do anything about the core once it's locked between sinew and horn, except for making minor reductions in width.)
The taper will be prepared after the horn is on the core. The taper is small after the initial drop on the sides of the grip.