Crab Bow Measurements
These are the measurements I have taken of a crab bow. The measurements are read directly off a digital micrometer. The paint surface was largely intact. I have included the measurements of one limb. The limbs were symmetrical and of equal length. There were minor discrepancies due to sinew bindings below the nocks.
This is under construction while I try and get the Table with the measurements to format correctly. I will add some pictures and sectional profiles as well.
This is under construction while I try and get the Table with the measurements to format correctly. I will add some pictures and sectional profiles as well.
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Inches
Distance from Nock Width Thickness
-0.5 0.362 0.467
0 0.509 0.551
1 0.515 0.580
2 0.604 0.642
3 1.184 0.662
4 1.306 0.666
5 1.383 0.701
6 1.440 0.727
7 1.475 0.770
8 1.519 0.821
9 1.530 0.753
10 1.576 0.589
11 1.591 0.560
12 1.594 0.519
13 1.600 0.494
14 1.606 0.475
15 1.599 0.469
16 1.592 0.444
17 1.580 0.428
18 1.547 0.441
19 1.482 0.488
20 1.366 0.518
21 1.184 0.611
22 0.927 0.807
23 0.758 1.027
24 0.867 1.148
Width of tip insert 0.140
Nock depth 0.195
Nock internal width 0.164
Base of nock to tip 0.912
Total length nock to to nock 48.0
Total length tip to tip 49.824
This a view of the bow from the side.
The grip. Please note that there are no external bindings. They are usually repairs, not normal additions to the bow. Tips have fine sinew reinforcements under the decoration. This is known from some Turkish bows as well.
The bow is decorated and has fine sinew covering both the belly and the back of the bow. From a damaged part of the bow, it appears that the sinew is first laid on longitudinally and then an extremely fine sinew is wrapped around the limbs from one end to another before the paint was applied. However, this might be an illusion caused by the the first layer of sinew being roughened tangentially.
The bow is decorated and has fine sinew covering both the belly and the back of the bow. From a damaged part of the bow, it appears that the sinew is first laid on longitudinally and then an extremely fine sinew is wrapped around the limbs from one end to another before the paint was applied. However, this might be an illusion caused by the the first layer of sinew being roughened tangentially.
Thanks, the best crabbow blueprint I have seen.
It's thinnest at the working area close to handle, can you see if the sinew, wood or horn is thinner?
It's thinnest at the working area close to handle, can you see if the sinew, wood or horn is thinner?
Thanks Bede. Very helpfull information.
Thank you Bede,This more than helps out,I have been looking forward to these measurements for a long time.I have just finished a bit of research in to the pigments used for these bows and the methods of how these were applied,I will post them here soon for everyone.
Thanks
P.J.
Thanks
P.J.
Thank you for the info and pictures. I don?t know much about these bows, known as crab bows, North Indian bows, Mughal bows or sometimes Lahore bows. So I?d like to ask some questions:
1) These bows are always covered with sinew over the horn on the belly? Are there more alternatives?
2) Those 3 crossed lines on the grip section seem to be present on most samples I have seen through pictures. I wonder if these are leather bands glued? is this just a decoration?
3) We have an idea about corresponding draw lengths to each type of bow. For example Turkish bows were known for short draw (in the 28-29" draw) and Chinese Manchu bows have a long draw (maybe from 34 to 36"). The crab bows are designed for something in the middle?
4) They seem to be inspired by the Turkish bows, except the abrupt transition from sal to kassan and straight tips. How would you compare these bows with the Turkish counterparts? maybe the same or inferior weapon in terms of performance and stability.
5) What about the material used for covering the back, leather, barl or just painted sinew?
1) These bows are always covered with sinew over the horn on the belly? Are there more alternatives?
2) Those 3 crossed lines on the grip section seem to be present on most samples I have seen through pictures. I wonder if these are leather bands glued? is this just a decoration?
3) We have an idea about corresponding draw lengths to each type of bow. For example Turkish bows were known for short draw (in the 28-29" draw) and Chinese Manchu bows have a long draw (maybe from 34 to 36"). The crab bows are designed for something in the middle?
4) They seem to be inspired by the Turkish bows, except the abrupt transition from sal to kassan and straight tips. How would you compare these bows with the Turkish counterparts? maybe the same or inferior weapon in terms of performance and stability.
5) What about the material used for covering the back, leather, barl or just painted sinew?
I will try to answer as many questions as I can.
- 1. All bows of this type that I have seen that are in good condition have sinew covered bellies. Adam in an article points out that the sinew is applied longitudinally. The bow in the picture has a damaged section on the bending part of the limb. I could see the sinew fibres running lengthways. I thought I could see a very fine layer of transverse sinew, but it may have been an optical illusion caused by residual brush strokes.
2. The three bands are either the edges of leather or bark strips or sometimes strings applied under the surface. They may have been a standard way of joining the pieces or the normal way to mark the centre of the bow.
3. Arrows associated with crab bows are always in the 27-29 inch range. The relationship to Turkish draw lengths is obvious. Mughal paintings often show draw lengths similar to the Turkish.
4. I have not shot an old bow or a modern reproduction of horn-sinew-wood so I have to go on reports from people who have. These bows are probably older in design than Turkish bows. There are some parallels with mediaeval bows in Central Asia and North China into the Ming Dynasty. McEwen told me that well made crab bows performed like Turkish bows. He said that they were very stable because of the relative width of the bending section of the limbs. He was not referring to flight bows. They came in various qualities and the good ones performed well and the poor ones were sluggish.
5. Adam, in his article described various processes. Sometimes there was a layer of silver foil under the paint as a moisture seal. I have seen ones with both thin bark under the paint and others with thin leather. Two I have appear to only have paint.
Thanks, that's valuable information.
Here's another sample of this style of grip:
Here's another sample of this style of grip:
Bede
Thanks for the measurements and photos.
The raised lines in the grip could have been used to get a more consistent hand position. Assuming that they were not just decorative - they often seem to be incorporated into the decoration.
I have seen a semi-dismantled crab bow that appeared to have had some sinew wrap around the sharp bend of the limb/siyah transition. The Society of Archer-Antiquaries Museum contains a Sind bow in poor condition that definitely had a short section of wrapping at a similar point. Strangely, the bulk of the sinew backing was on top of the wrap on the Sind bow, so the wrapping would have had no effect at stopping the backing pulling away from the limb as it dried.
I wish more information was available on the links between the bone-reinforced early medieval bows and the Turkish, crab and other later designs. Unfortunately as most of the earlier archaeological evidence is based on bone plates alone, the evidence stops as the plates fall out of use.
Figure 423 in Nicole, Arms and Armour of the Crusading Era 1050-1350: Islam, Eastern Europe and Asia, Greenhill Books, 1999 shows a line drawing of three bows of Turkish looking shape found in a collapsed room in upper Mesopatamia, one of which was carbon dated to 1195. So the Turkish design may be quite early.
Andrew
Thanks for the measurements and photos.
The raised lines in the grip could have been used to get a more consistent hand position. Assuming that they were not just decorative - they often seem to be incorporated into the decoration.
I have seen a semi-dismantled crab bow that appeared to have had some sinew wrap around the sharp bend of the limb/siyah transition. The Society of Archer-Antiquaries Museum contains a Sind bow in poor condition that definitely had a short section of wrapping at a similar point. Strangely, the bulk of the sinew backing was on top of the wrap on the Sind bow, so the wrapping would have had no effect at stopping the backing pulling away from the limb as it dried.
I wish more information was available on the links between the bone-reinforced early medieval bows and the Turkish, crab and other later designs. Unfortunately as most of the earlier archaeological evidence is based on bone plates alone, the evidence stops as the plates fall out of use.
Figure 423 in Nicole, Arms and Armour of the Crusading Era 1050-1350: Islam, Eastern Europe and Asia, Greenhill Books, 1999 shows a line drawing of three bows of Turkish looking shape found in a collapsed room in upper Mesopatamia, one of which was carbon dated to 1195. So the Turkish design may be quite early.
Andrew
Andrew,
You and I both know that someone cannot get a precise date from Carbon 14 that is accurate down to a year at 1,000 years into the past. Dr Nicolle sometimes includes information of more precision than is technically possible. In more recent works, particularly about the Tibetan material in the Metropolitan Museum Art in New York, spreads of several hundred years are given for more recent material.
I too have seen bows with various types of bindings at weak points. Sometimes they were sinew and other times crude rawhide. In Korea, highly reflexed bows are often repaired by bindings. In some cases they are bound before any issues have appeared. In modern Mongolian bows, nylon bindings can be applied at the end of the manufacture. Your description of the Sind bow is unusual even in this context, but Sind bows are the ones with the most points of failure. One of the Sind bow shaped Afghan bows in the Grayson Collection has two iron rivets through the hand to prevent the horn lifting.
Getting back to the other point of your post, the origins and relationships of the various "modern" composite bows, I have found crab bows as very interesting. Firstly, the lack of reflex between the kasan equivalent and the bash equivalent combined with the strong reflex at the kasan to sal boundary initially suggests a connection with early non-contact siyah design.
However, the internal construction of the crab bow is much more complex and clearly not in a direct line of descent. The X-Ray images I have and the dissected bow I examined at the Koppedrayers' house show that the ear section is nearly rectangular for most of its length and the ridge is mostly sinew with a tiny wooden spine contributed by the core. The Koppedrayer bow had the splice for the siyah was in the last section of the bending part of the limb before the change in angle. The thin horn on the belly did not even reach the angle and just covered the splice. This core shape has more in common with the bows excavated in China with birchbark coverings. In these bows the triangular section of the kasan has not yet developed.
It looks to me that horn on the bow I illustrated here was not as wide as the limb. This is consistent with the Koppedrayer bow which had a horn strip almost a third of the width of the limb. In a communication from Edward McEwen, I was informed that many crab bows had the horn wrap around the curve of the angle between the siyah and the bending section of the bow. It did not continue much up the siyah from that point.
The construction of the cross-section of the Koppedrayer bow at the bend had the belly built out with sinew. The published cross-sections in The Grey Goose Wing show much more wood in the siyahs which I think would be more efficient in limb mass. Sinew is heavier than wood. It makes me think that the bowyers in one case were trying to make their bows look like the more efficient type by building out the belly.
On the back, building the kasan up with a ridge of sinew would be an efficient way of stiffening it without changing the core. It seems to me that the Turkish and Persian solution of shaping the core into a stronger triangular section is a more advanced development by way of reducing the mass while still achieving the required stiffness.
The question then becomes, did the crab bow come first and represent the transition between rectangular kasans and triangular ones or is the ridge on these bows a retro-fitting by adding sinew to copy the ridges on other bows.
Many Sind bows have sinew ridges on the back of the bending part of the bow which take much of the tensile load. This may be an old tradition lost elsewhere or it could be an innovation to improve performance. Either way, it shows that Indian bowyers were masters of many techniques and were capable of complex design.
I am trying to find a way to scan my X-Ray images. I will post them here if I succeed. Otherwise you will only get drawings.
You and I both know that someone cannot get a precise date from Carbon 14 that is accurate down to a year at 1,000 years into the past. Dr Nicolle sometimes includes information of more precision than is technically possible. In more recent works, particularly about the Tibetan material in the Metropolitan Museum Art in New York, spreads of several hundred years are given for more recent material.
I too have seen bows with various types of bindings at weak points. Sometimes they were sinew and other times crude rawhide. In Korea, highly reflexed bows are often repaired by bindings. In some cases they are bound before any issues have appeared. In modern Mongolian bows, nylon bindings can be applied at the end of the manufacture. Your description of the Sind bow is unusual even in this context, but Sind bows are the ones with the most points of failure. One of the Sind bow shaped Afghan bows in the Grayson Collection has two iron rivets through the hand to prevent the horn lifting.
Getting back to the other point of your post, the origins and relationships of the various "modern" composite bows, I have found crab bows as very interesting. Firstly, the lack of reflex between the kasan equivalent and the bash equivalent combined with the strong reflex at the kasan to sal boundary initially suggests a connection with early non-contact siyah design.
However, the internal construction of the crab bow is much more complex and clearly not in a direct line of descent. The X-Ray images I have and the dissected bow I examined at the Koppedrayers' house show that the ear section is nearly rectangular for most of its length and the ridge is mostly sinew with a tiny wooden spine contributed by the core. The Koppedrayer bow had the splice for the siyah was in the last section of the bending part of the limb before the change in angle. The thin horn on the belly did not even reach the angle and just covered the splice. This core shape has more in common with the bows excavated in China with birchbark coverings. In these bows the triangular section of the kasan has not yet developed.
It looks to me that horn on the bow I illustrated here was not as wide as the limb. This is consistent with the Koppedrayer bow which had a horn strip almost a third of the width of the limb. In a communication from Edward McEwen, I was informed that many crab bows had the horn wrap around the curve of the angle between the siyah and the bending section of the bow. It did not continue much up the siyah from that point.
The construction of the cross-section of the Koppedrayer bow at the bend had the belly built out with sinew. The published cross-sections in The Grey Goose Wing show much more wood in the siyahs which I think would be more efficient in limb mass. Sinew is heavier than wood. It makes me think that the bowyers in one case were trying to make their bows look like the more efficient type by building out the belly.
On the back, building the kasan up with a ridge of sinew would be an efficient way of stiffening it without changing the core. It seems to me that the Turkish and Persian solution of shaping the core into a stronger triangular section is a more advanced development by way of reducing the mass while still achieving the required stiffness.
The question then becomes, did the crab bow come first and represent the transition between rectangular kasans and triangular ones or is the ridge on these bows a retro-fitting by adding sinew to copy the ridges on other bows.
Many Sind bows have sinew ridges on the back of the bending part of the bow which take much of the tensile load. This may be an old tradition lost elsewhere or it could be an innovation to improve performance. Either way, it shows that Indian bowyers were masters of many techniques and were capable of complex design.
I am trying to find a way to scan my X-Ray images. I will post them here if I succeed. Otherwise you will only get drawings.
Nice bow Jose. Where did the pic come from? Is that a gem type thumb ring? Yokhua told me he thinks the thread decoration on the grip is a stylized representation of a remnant lashing to help keep the horn down. Makes some sense.
Then what about the nock tips? I see some of them are solid horn.
Then what about the nock tips? I see some of them are solid horn.
Sorry, I didn't mention the source. Here it is:
http://www.jfsantiquearms.com/stephens_ ... on/o4.html
http://www.jfsantiquearms.com/stephens_ ... on/o4.html
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DIST /cm Width Thick
-1,27 0,92 1,19
0 1,29 1,4
2,54 1,31 1,47
5,08 1,53 1,63
7,62 3,01 1,68
10,16 3,32 1,69
12,7 3,51 1,78
15,24 3,66 1,85
17,78 3,75 1,96
20,32 3,86 2,09
22,86 3,89 1,91
25,4 4 1,5
27,94 4,04 1,42
30,48 4,05 1,32
33,02 4,06 1,25
35,56 4,08 1,21
38,1 4,06 1,19
40,64 4,04 1,13
43,18 4,01 1,09
45,72 3,93 1,12
48,26 3,76 1,24
50,8 3,47 1,32
53,34 3,01 1,55
55,88 2,35 2,05
58,42 1,93 2,61
60,96 2,2 2,92
Width of ti 0,36
Nock depth 0,5
Nock intern 0,42
Base of noc 2,32
Total lengt 121,92
Total lengt 126,55
A close examination of one of the X-Rays I have of the grip of one of my crab bows shows a very fine line that appears to be part of a V-splice. The published diagram of a Persian bow that was in Turkish Archery and the Composite Bow had the grip section applied like a riser on the back of the centre of the bow. In the belief that there was a strong relationship between the later bows used in Persia and the late bows in India, I had thought this easy method of construction would have been used there (India) too. After all, the Manchus and the Koreans used this system. However, the X-Ray looks different and, taking into account the wider limbs of the crab bow, the position and size of the splice is very similar to Turkish bows.
The crab bow seems to have much thinner wood and horn sections than other composite bows of similar lengths. This is obviously a necessity when you consider how little of the bow limbs bend.
Regarding the lines on the grip, string-under-leather decoration is very common in Turkish and Persian sword scabbards. The wooden cores of the scabbards are decorated with string laid in patterns on glue and then wet leather was glued over it and pressed into the designs. Considering the grip area is much more stable than the transition between the grip and the bending limb, there is little need for a strengthening binding. It would be useful for locating the hand and centring a cloth cover for the handle. Swords often had wrappings on the grips made from silver bullion tape that prevented the hand slipping due to sweat (or blood). The tapes could be unwrapped and washed or replaced when they became dirty. I have seen pictures of composite bows with the handles wrapped in the same way. I don't know if this was common, but many grips show no sign of wear.
The crab bow seems to have much thinner wood and horn sections than other composite bows of similar lengths. This is obviously a necessity when you consider how little of the bow limbs bend.
Regarding the lines on the grip, string-under-leather decoration is very common in Turkish and Persian sword scabbards. The wooden cores of the scabbards are decorated with string laid in patterns on glue and then wet leather was glued over it and pressed into the designs. Considering the grip area is much more stable than the transition between the grip and the bending limb, there is little need for a strengthening binding. It would be useful for locating the hand and centring a cloth cover for the handle. Swords often had wrappings on the grips made from silver bullion tape that prevented the hand slipping due to sweat (or blood). The tapes could be unwrapped and washed or replaced when they became dirty. I have seen pictures of composite bows with the handles wrapped in the same way. I don't know if this was common, but many grips show no sign of wear.
there is an angle around 25cm from the tip. Oddly the limb thickness/widths are not affected by this.
Is the whole siwayh rigid on wood only, or is it bending with horn/sinew or something in betheen?
Is the whole siwayh rigid on wood only, or is it bending with horn/sinew or something in betheen?
There is a transition between the triangular kasan-like part of the gosha and the bending part of the the limb. There the thickness changes abruptly. The whole of the siyah or gosha is rigid. When the bow was heavy enough to require it , the tip section is spliced into the triangular section so that a heavier stronger piece of wood can be used. This is the purpose of the horn inlay in the tip too. The only part of the bow that bends are the sections between the grip and the siyahs.
The bow makers who made these bows went to a lot of trouble to make sure the limbs were stable and the siyahs were rigid. Those who understand the equations will realise that there are minor movements in the rigid parts of bows, but they are usually so small as to be not noticed by the human eye.
The bow makers who made these bows went to a lot of trouble to make sure the limbs were stable and the siyahs were rigid. Those who understand the equations will realise that there are minor movements in the rigid parts of bows, but they are usually so small as to be not noticed by the human eye.
On some old bows the tip has been entirely eaten off by insects. This may mean that the entire tip is horn. We all await construction details.
Jack,
Do you mean all of the tip above the nock or the whole slender portion of the siyah?
I have seen old Manchu bows where the very tip of the siyah was a buffalo horn insert and the nock was carved in it. There are also Turkish bows where a piece of ivory is inserted for the full length of the baş so that the nock is carved wholly in ivory.
Do you mean all of the tip above the nock or the whole slender portion of the siyah?
I have seen old Manchu bows where the very tip of the siyah was a buffalo horn insert and the nock was carved in it. There are also Turkish bows where a piece of ivory is inserted for the full length of the baş so that the nock is carved wholly in ivory.
Crab bows I have seen are lacquered/painted entirely and this limits intrusion by insects. Just before the bow is strung for the first time, the nocks are cut at the tips. Old bows sometimes have the tips missing entirely which is a clue that the nock was cut in solid horn; in the manner of some Qing bows.
I would like to see a drawing of the complete construction. Was your x-ray successful?
I would like to see a drawing of the complete construction. Was your x-ray successful?
Jack,
I have seen bows where a tip has broken. Usually there is a bit of wood on each side. It always looks like the horn was eaten out to the notch for the string and the tip snapped off because it was weakened. I have one like that so I will get it out and have a look.
I have an idea for scanning the X-Rays. I am going to duplicate the setup for slide copying by putting a reflector above the film and see if that will give me a better image.
The wooden core and elements of the paint seem to be denser to X-Rays than the horn or sinew. I picked a bow to X-Ray that had most of the paint abraded away, but even so there were flecks of dense mineralised paint.
I have seen bows where a tip has broken. Usually there is a bit of wood on each side. It always looks like the horn was eaten out to the notch for the string and the tip snapped off because it was weakened. I have one like that so I will get it out and have a look.
I have an idea for scanning the X-Rays. I am going to duplicate the setup for slide copying by putting a reflector above the film and see if that will give me a better image.
The wooden core and elements of the paint seem to be denser to X-Rays than the horn or sinew. I picked a bow to X-Ray that had most of the paint abraded away, but even so there were flecks of dense mineralised paint.
Bede, sorry for the delay in responding.
The bows mentioned by Nicolle were reportedly found in a collapsed structure with a large number of other military artefacts. Although the carbon date error ranges are missing (and may well be large), a number of the finds were carbon dated and these cluster the first half of the 13th C. The bows are only illustrated as simple line drawings, but show bows with no set back in the grip and a smooth curve into the (possibly triangular cross-section) siyah.
The Turkish bow seems fully developed by the Bayazit period in the 15th C, and in the 14th C Taybugha describes bows that seem to be Turkish/Persian. I would not have thought it impossible that bows with Turkish/Persian-like characteristics (no grip set-back, smooth curves into siyahs, horn on siyah belly) were present in the 13th.
(I wonder if Tatbugha's munfasila bow type ? that comprising several elements fitted together ? was the term for the older angled-eared bows).
When do you think the general Turkish/Persian characteristics developed?
In terms of shape, you can get a crab-like bow by taking the more reflexed of the two Shiluustei sum bows, extending the horn and sinew up the siyah and widening it. As you discuss, the construction is somewhat different. Is it possible that the shape was fixed by tradition, but the bowyers changed the invisible core construction to make them easier to build?
The stripped down crab I have seen had long V-splices to the grip, and evidence of another in the kassan/sal boundary. The siyah still had its covering and sinew, so no other splices were visible. The tip is of wood only.
The horn only covers about 3/4 of the limb width, the remainder is filled out with sinew. The Pitt-Rivers museum has a number of sectioned composite limbs, including a crab bow which has the same form. The overall quality of construction did not seem high ? wavy grain in core, inconsistent core and horn thicknesses etc ? though the bow had broken in one limb so may not have been the best.
Andrew
The bows mentioned by Nicolle were reportedly found in a collapsed structure with a large number of other military artefacts. Although the carbon date error ranges are missing (and may well be large), a number of the finds were carbon dated and these cluster the first half of the 13th C. The bows are only illustrated as simple line drawings, but show bows with no set back in the grip and a smooth curve into the (possibly triangular cross-section) siyah.
The Turkish bow seems fully developed by the Bayazit period in the 15th C, and in the 14th C Taybugha describes bows that seem to be Turkish/Persian. I would not have thought it impossible that bows with Turkish/Persian-like characteristics (no grip set-back, smooth curves into siyahs, horn on siyah belly) were present in the 13th.
(I wonder if Tatbugha's munfasila bow type ? that comprising several elements fitted together ? was the term for the older angled-eared bows).
When do you think the general Turkish/Persian characteristics developed?
In terms of shape, you can get a crab-like bow by taking the more reflexed of the two Shiluustei sum bows, extending the horn and sinew up the siyah and widening it. As you discuss, the construction is somewhat different. Is it possible that the shape was fixed by tradition, but the bowyers changed the invisible core construction to make them easier to build?
The stripped down crab I have seen had long V-splices to the grip, and evidence of another in the kassan/sal boundary. The siyah still had its covering and sinew, so no other splices were visible. The tip is of wood only.
The horn only covers about 3/4 of the limb width, the remainder is filled out with sinew. The Pitt-Rivers museum has a number of sectioned composite limbs, including a crab bow which has the same form. The overall quality of construction did not seem high ? wavy grain in core, inconsistent core and horn thicknesses etc ? though the bow had broken in one limb so may not have been the best.
Andrew
Hello Bede, very good information! I?m wondering how such a sharp bending in the beginning of the ear can be achieved. Possibly the only solution is using natural curved parts of trees. I tried some maple soaked in water for about 2 weeks and it broke. I have yet to try fresh yew, maybe it works. Yew can be heat bent very good.
Andrew, you mentioned illustrations depicting these 13th century bows; could you post some of these here? I?m curious about these bows. The invention of the "modern" composite with contact siyah/ string bridge is a very interesting question.
Best regards, JJ
Andrew, you mentioned illustrations depicting these 13th century bows; could you post some of these here? I?m curious about these bows. The invention of the "modern" composite with contact siyah/ string bridge is a very interesting question.
Best regards, JJ
JJ
The drawing is copyright so I am afraid I cannot post it here.
Andrew
The drawing is copyright so I am afraid I cannot post it here.
Andrew
I dont know about net copiright ,but newspapers law about pics and drawings works if you describe source near the pic.
That is a good question. Judging by the centimeter grid in the pictures, the triangular part is about 1,5cm thick. This must be hard to bend in this small radius.JJ wrote:
Hello Bede, very good information! I?m wondering how such a sharp bending in the beginning of the ear can be achieved. Possibly the only solution is using natural curved parts of trees. I tried some maple soaked in water for about 2 weeks and it broke. I have yet to try fresh yew, maybe it works. Yew can be heat bent very good.
I could imagine that it is spliced similarly to Kviljo's construction seen here: http://198.170.107.188/phpBB2/viewtopic.php?t=1465
The X-rays should tell.
Daniel
I have just checked the X-Ray of a similar crab bow and, at the point where the limb is about 21 mm thick, the wooden core is about 10 mm. The Koppedrayer bow is similar if a little thinner in the core.
I believe from looking at the cut up bow and the x-Rays that the bend in the siyah is artificially produced. I am not saying that you couldn't make this kind of shape with wood that has grown to the right shape, but bending is more straight forward. Considering the amount of sinew that has been applied to the back, a slight weakness in the core would be insignificant. I have some sandalwood that has a branch coming out on one side and I will try to use this for siyahs, but I think the other way will be easier and is more likely for traditional commercial production.
Making some deductions from the X-Ray, I would guess that the core increases in depth immediately after the bend. This might even reflect the way in which it was made. By changing the thickness of the raw core, a weak spot could have been made where bending would occur preferentially near by.
I believe from looking at the cut up bow and the x-Rays that the bend in the siyah is artificially produced. I am not saying that you couldn't make this kind of shape with wood that has grown to the right shape, but bending is more straight forward. Considering the amount of sinew that has been applied to the back, a slight weakness in the core would be insignificant. I have some sandalwood that has a branch coming out on one side and I will try to use this for siyahs, but I think the other way will be easier and is more likely for traditional commercial production.
Making some deductions from the X-Ray, I would guess that the core increases in depth immediately after the bend. This might even reflect the way in which it was made. By changing the thickness of the raw core, a weak spot could have been made where bending would occur preferentially near by.
Bede, do you know the draw weight of the measured bow? Around 100#? Around 50#?
Daniel,
I have no way of measuring the bow for weight. I really need an exact replica to get some idea. The bow is several hundred years old (between 150 and 250). I can get the mass of the bow. Some experienced bowyers may be able to make an estimate from that and the dimensions.
I have no way of measuring the bow for weight. I really need an exact replica to get some idea. The bow is several hundred years old (between 150 and 250). I can get the mass of the bow. Some experienced bowyers may be able to make an estimate from that and the dimensions.
What is a typical width of a horn insert for ear reinforcement? Is it a slim insert, maybe a bit thicker than a horn insert for arrow nocks, or is it the bulk material?
Regarding the horn insert in the tips of the crab bow:
I have seen some variation. I have probed into the damage tip of the measured bow and the width of the horn is 3.5 mm.
The bow mass is 450 grams. The next two posts will have the cross sections.
I have seen some variation. I have probed into the damage tip of the measured bow and the width of the horn is 3.5 mm.
The bow mass is 450 grams. The next two posts will have the cross sections.
These are the cross sections of the measured crab bow.
This page covers down to the centre of the grip. These cross sections used a profile gauge for data. The profile gauge is only accurate to about 1.5 mm so I visually corrected the drawing from the bow. I will be refining the cross sections later.
Thanks, Bede. Very usefull information.
Yes, that's great, thank you very much!
I've started making one of these, but am struggeling with deciding how to make the "kasan" core piece. All the "kasan eye"-bend is made on the kasan piece, I guess.
Is there any evidence that this was steam-bent from a straight piece of wood, or have they used a naturally bent piece? If it is steambent, how thick is the core at the center of the bend? I'm just not sure if I will be able to bend such a sharp bend with the required thickness? Perhaps the wood is not that thick, and that the ridge is mostly made up of sinew?
I've also been wondering a bit why the limbs are straight at the outer presumably non-bending parts, while the bending section of the limbs have a lot of reflex. Perhaps the added shear and tension on the glue line is not such a big problem with these sinew-wrapped bows? And perhaps having the bending section close to the grip makes the bow more stable? - is that a bit issue with these bows?
Is there any evidence that this was steam-bent from a straight piece of wood, or have they used a naturally bent piece? If it is steambent, how thick is the core at the center of the bend? I'm just not sure if I will be able to bend such a sharp bend with the required thickness? Perhaps the wood is not that thick, and that the ridge is mostly made up of sinew?
I've also been wondering a bit why the limbs are straight at the outer presumably non-bending parts, while the bending section of the limbs have a lot of reflex. Perhaps the added shear and tension on the glue line is not such a big problem with these sinew-wrapped bows? And perhaps having the bending section close to the grip makes the bow more stable? - is that a bit issue with these bows?
The reflex in these bows in mostly concentrated in the kasan eye, not in the sal. That, with the reflex in the grip, makes the sal quite straight. It would be quite Ok to start with the sal nearly straight in these bows, with some reflex added as the sinew dries. As to the kasan's core thickness, it is probabbly no more than 1/2 inch, the rest is sinew and (very thin) horn.
Adam
Adam
The one I saw cut up had the kasan core only about twice the thickness of the sal core and less than one third the thickness of the kasan with sinew. If there was any horn, it was paper thin. I could not see any horn past the splice.
I don't think this was the only way to make them or the best. I think Adam's advice would make a better bow.
I don't think this was the only way to make them or the best. I think Adam's advice would make a better bow.
Thanks for the brilliant responses, guys.
That cut-up bow should have been published somewhere! The information that the cut up chinese bow (at atarn.org) gives is priceless.
On bending the kasan piece - I guess one could shape the kasan ridge before the bend, to prevent splinters.
And, I forgot to mention it: Thanks a lot for publishing the dimentions and cross sections. The cross sections will be especially helpful.
That cut-up bow should have been published somewhere! The information that the cut up chinese bow (at atarn.org) gives is priceless.
On bending the kasan piece - I guess one could shape the kasan ridge before the bend, to prevent splinters.
And, I forgot to mention it: Thanks a lot for publishing the dimentions and cross sections. The cross sections will be especially helpful.
Bede,
somehow I have missed your last posts....
Thank you very much for the cross sections, they?re brilliant. That?s a lot of work... I?ve never seen before so many, and precise cross sections of a crab bow. That?ll be a great help for bowyers.
Hope to see you on atarn.
JJ
somehow I have missed your last posts....
Thank you very much for the cross sections, they?re brilliant. That?s a lot of work... I?ve never seen before so many, and precise cross sections of a crab bow. That?ll be a great help for bowyers.
Hope to see you on atarn.
JJ
Kviljo,
The ridge I saw on the cut up bow was only about a millimetre high on the core despite the thickness of the ridge on the completed bow. To make that, I think the core of the kasan was made a millimetre thicker for bending and then adzed away afterwards. Splinters could be removed at the same time.
Possibly the kasan core was made even thicker for bending. This would allow differential thickness being used to affect the degree of bending at each section.
The ridge I saw on the cut up bow was only about a millimetre high on the core despite the thickness of the ridge on the completed bow. To make that, I think the core of the kasan was made a millimetre thicker for bending and then adzed away afterwards. Splinters could be removed at the same time.
Possibly the kasan core was made even thicker for bending. This would allow differential thickness being used to affect the degree of bending at each section.