Bow from inner curv

All bends are made before joining the core parts and before gluing the horn strips. I do not have the dimensions of this bow any more. Perhaps you can approximate from the picture? I now found the war bows should have more flex in the transition between the kasan and the sal than this bow. It makes the bows actually faster and more stable in use. Too much curvature in the kasan requires a shorter string/greater brace height as well.

Good luck

Adam

On my other I did glue a steam bend wood on the kasan and fade it from a ridge at knee to the sal. But I see you have more reflex then I got. That way should give more flex I guess and put in more bend from begining, 45 degree maybe?
I don't draw more then 26" so I want full power early.

This bow 48" gives about 70 lb but is slow, only 200fps with 400 grains. I's also made of inner curve that are 32 mm wide. The core wood is 36 mm and I did fill the gap with sinew on belly side.

The war bows had the thinnest spot in sal very close to kasan (or rather the kasan eye - where the kasan begins with the ridge). This makes the bow flex there during the draw and in result the sal becomes longer as well.

The kasan length was around 16-18cm or so for most bows. Bows with this construction have limbs basically straight at full draw, except for the recurved tips which remain rigid.

While the kasan eye area is reflexed from the start, the kasan itself should not be curved too much. Otherwise the bow will be difficult to stabilze and may require a greater brace height.

Adam

http://www.atarn.org/islamic/akarpowicz/fig%2012.jpg
At this picture the eye does not bend in that manner you mean?
But more bend there, would not that give longer draw?

The bow on the picture was not fully drawn. At full draw the limbs would be almost straight at the kasan eye.

More bending there effectively lengthens the bending section of limb. It means the stresses are spread-out over more limb and the bow is not as stressed overall. Such bows keep the reflex better and can be drawn further with less string follow.

Adam

I think I know what you mean. As for me I should make shorter bows like this 44", 90lb at 26" (one of Puzio's bows).
I got the core and horn done and need to decide the length before I make the kasan eye.
I'm thinking of making the ear splice all way down the kasan, I have a natural 45 degree wood for that. It's 20 cm + 15 cm and if cut in two I have both ears and kasan done.

This is first picture I found that shows that it bends at the kasan/sal. Is there other pictures? Most bows seems to be stiff at that spot.
http://198.170.108.27/phpBB2/files/dsc02980zip_163.jpg

The only style of bow of similar construction (with the distinct sal, kasan and the tip) that does not bend at all in the kasan eye area is the Mughal bow from India. Maybe the Sind bow as well. All other show bending to a varying degree in this place.

Adam

Ok, I will do some experiment with the kasan/sal and see if it's an effect of the way they made the bows or a calculated design with unknown advantage.

This is today, I will try to glue the horn with cable tie. It should do with some wedge on every strip.

Adam,
I think some of the Persian bows do not bend at the sal/kasan junction either, based on their geometry.

Well, it's now glued with cable tie. Took about 25 at each limb but I didn't make wedge, I clamp at center instead.
The cable tie does draw enough and does not twist the core.
As you see from picture the core took more then an inch reflex from the glue job.

Bede, do you have an example of the Persian bow that does not bend at the kasan eye? All bows identified as Persian I have seen would be bending when used, as judged by the thickness of the limbs there. The degree of un-strung reflex is irrelevant in these considerations.

The Indian bows are often confused with Persian bows. Maybe there are hybrids as well.

Adam

Adam,
I don't have copyright to the photos I have access to. The kasan ends in an angle less than a crab bow, but still pronounced. The bows are signed and dated and in Iranian collections.

I will try to do a drawing for you. The bows are completely covered and probably with parallel horn strip bellies. Judging by these bows, at least two in the Grayson Collection are Persian too. This is supported by the inscriptions and style of painting. However, Northern India imported both bows and bow makers during the Mogul period.

Bede:

Could you please send me the link to the two Persian bows from the Grayson collection (the ones similar to the Iranian bows)? I remember I had doubts about the origin of some of the bows there. The angle of the bend is not important, only the relative thickness, so the drawing will not likely be helpful.

Adam

Adam,
I will look up the notes I took and get you the item numbers. I remember that the kasan was thick where it joined the sal and more angled than a Turkish bow would be. I may have taken my own photos. I will look.

You might try looking for them here:

http://anthromuseum.missouri.edu/grayson/grayson.shtml

Thanks for the link. I see two Persian bows in the collection: one strung, the other not strung. The strung bow has the kasan eye areas obviously bent and almost straight already. The other bow has the kasan ridge ending at or before the apex of the bend. It means the bow is still flexible up to the kasan eye and the bend will flex in the bow when strung and drawn. It is difficult to say by how much the bow will flex there without the measurements of the limb thickness and width, but the bow will flex at least to some degree. These two bows, as I see it, behave exactly like the typical typical Persian bows.

The bows classified as Mughal have the kasan ridge further down the limbs, past the bends, towards the sal sections. It means the bows do not flex at all at the bends. When strung and drawn the bows will have only the sal sections bending and the kasan reflex will be retained.

Adam

The painted bow (MAC 1994-0651) has been strung since before Dr Grayson acquired it. It looks on inspection to have distorted with age and pressure. The other bow (MAC 1994-0639) in the flesh is more like a chahar kham bow at the sal/kasan junction. This is how it appeared when I was handling it. The joint is thicker than it appears in the photo. Undoubtedly you are right about there being bending at the joint, but I do not think it was as much as in a Turkish bow. The painted bow does not look as if it ever performed well, but that is a subjective assessment.

Adam, have you dissected a Mogul bow? I would be interested to find out the mechanics of the joint between the sal and the kasan because I can see two ways to accomplish it. Some bows I have seem much more robust than others in the kasan/sal joint.

McEwen showed me a dissected crab bow a while back. As I recall there was a separate splice-in piece between the sal and the kasan, because the bend there was acute as usual. I do not believe, however, the Persian bows always had this joint, because the bending there is more gradual, more like in the Turkish bows and the core could be safely bent to this lesser angle. I do not think the method of construction matters much for the working of the bows - the overall thickness at each section plus the relative amounts of the three components are more important.

The tips in my crab bow had the usual splice as well, although I think it is possible it could be sometimes ommited, since the angle betw. the kasan and tip is very slight.

The dissected bow had the sinew thickness much greater than other bows - about one half of the limb in sal and (if I remember correctly) in the kasan/sal joint. These bows are basically mostly made of sinew.

Adam

Adam,
I agree that most Persian bows were probably closer in shape to Turkish bows rather than Indian ones. I also agree that the sal/kasan transition is much less angular than in crab bows. The main similarity between Persian and Indian bows in my view is the sinew wrapping and the multiple horn slats. The strong cultural links between Turkey and Persia on one hand (particularly the Qizilbash during the Safavid period) and Persia and India on the other (Persian craftsmen and scholars were migrating there from at least as early as the Delhi Sultanate) easily explains the similarities.

Rereading one of your articles reminded me that you pointed out the similarity in shape between earlier Turkish bows and Persian bows in the Topkapi Palace Museum.

I have put on 40 gram sinew and dry it for 48 hour (don't tell it's short time :) )
What has happens is that the shrinking sinew draw the glue line between the horn strips apart. I bend the bow to 2" brace on my knee and it comes around nice but I feel that on limb is weaker. The one with bigger gap. Maybe the the horn strips can be fixed afterwards. Or just make new single piece horn strips and put them on. If I let the sinew shrink more it will be more difficult to put on flat strips :(

Ok, now the horn strips are removed. But first I did brace it at 4". It took a load of +35lb to bend the limb so I could put on the string. 35+35=70lb. It's maybe not the exact load but it tells me that the bow could be much stronger then I can handle.
Without the horn I see how the core looks at brace and full draw. Next core I will make the core-handle splice sharper and without any gap.. Now the bend starts at the point of splice so it's a weak point.
About the inner strips, the quality of horn is more important, any dry ugly horn will crack when worked. But it seems that when at core and good glue bond they take the load anyway. One strips is ok, I have bows that are made from inner curv, but two narrow strips is much more difficult to make a bow from. But it can be done :)

The bow is 44" n/n and drawn to 26" at back. Limbs are different and it comes from start of bend. This is something I see in many bows. The belly is a little round from the sinew shrink. I don't think its worth to make new horn strips for this bow.

I will do one more test before I put it in fire, take shorter horn strips from sides. I keep the bow in my shop so it will nor dry under 15% mc. With 2-3 mm horn it could still be a nice youth practice bow.

Horn quality is better on sides. I got two 10-11" strips about 5 mm thick. Under fade I keep it thicker and at bending part 3 mm. My hope is that the bend moves a little to mid limbs. At handle I can use horn, bone or wood. Horn is easy to work, bone is harder. Under kassan I think I will use wood, lower mass.

Now with 5 piece horn from outside. Total mass 400 gram right now.

One week of drying time and first brace. A little uneven in limbs, think I can fix that. Left limb is stronger, if I scrape a little at midlimbs, can that be enough? It weights 40 lb at 17 inch. If you think the string looks stage, it's an old 90lb ELB string I made loop knots on :)

One week has pass and I have removed the weak horn. It start to delaminate at shooting. I made a new from an other side. Now it's better in balance. It draws 60 lb at 23 inch and it's more then I intend. At my draw length it will be about 70 lb and thats no problem, but as a practice bow for other it's to heavy. How can I take it down in weight?
Bow is at 6.5" brace 38" n/n, 3mm horn, 4mm ash, and 2-3 mm sinew (60 gram dry)

Right, I guess the bow is done. I shot it steady with 24 gram (calculated 62-64lb) over 190 fps and had a few over 200 fps. I have still one inch more to full draw (25" bellyside). Some day I will put on some kind of finish also.
The kasan is 30mm wide and I can save few grams if I make it more narrow.

The easiest way to reduce the weight of a composite bow is to leave it strung for a few days. However, it is worthwhile to control the curvature by using something like the Korean pogung on each limb. This is a loop of leather that fits over the kassan and string to prevent the curves of the limbs getting out of balance

You should be able to recover the lost draw weight by leaving the unstrung bow belly-up in the sun for a few hours.

Just keep it at brace :) ok.
This bow started as a inner curv bow but did end as horn side bow.
My other innercurv bow come out a little to high in mass, 440 gram. So I did remove all sinew at kasan and removed wood, put back some sinew and get it down under 400 gram. And then I measure it on a scale to 80 lb. With 400 grains it shot steady over 240 fps and I got one at 255 fps. I think I can get few fps more if I hit the mark on arrow, I was short all time. 28" at belly ad I did 27-27.5.

Over 240fps at 5 grains per pound (400gr/80lb) is about what one can expect for a war bow. Congratulations Redhorse. I found the mass of the bows can be lowered still further for the ratio of bow mass in grams per draw weight in lb down to around 3. For your bow is is 400 grams/80lb = 5, still very good if a bow is more than 44in ntn.

Adam

I took an carbon arrow (it's a tube) and put in welding rods till I get 53 gram. So I had 10grains/lb. Did a test release, got 170+, draw longer got 180+, a little longer 190+ and finally close to full, 213fps. I did not hit the 28" mark but had shots over 200fps.
I can't guaranty the scale for bow weight, scale for arrow or the crono.

And those 213 is impossible, would be over 100% efficiency :(
but at 94% it will do 200 fps. 190+ I do steady, 87%.

I took a brand new Chrony Beta out of box and shot it in row with my old crono. 1-2 fps difference, the one in front was always faster :)

Just an update.
I have made some adjustment and have 361 gram mass today.
At 25" belly its 77 lb and shot 355 grains at 225 fps. It's 60% eficiency, not so impressive :(
[external image]

Did the shape change much when you were reducing mass and where?

Kind Regards
David

Not at all, I remove the horn plats on ears, took of 2 mm at kasan width. fade out the horn under kasan. scrape all sinew smooth. If I risk the stability I could take more from the kasan.
But I don't think I can improve the bow so much that it's worth it.
My other that was 80 lb was so much faster and more efficient, it was a few inch longer and less angle at ears.
I did try with 10/lb but it was a disaster, just over 160 fps. The other was faster without any adjustment.
Next bow will be longer.
Before I destroy or sell the bow I will try with longer draw and lighter arrows, maybe it does fine that way.
The one I send to Steve was much better from beginning.

I did remove material at the kasan and are down at 351 gram now.
With 378 grains I did shot 229fps. Its 66% efficiency, better but still low.
496 meter in vacuum?

This is what it looks alike today at 26" draw.
Should I try to balance the limbs?

Ok, I did this. I made the Turkish tiller Klopsteg describe in his book.
3 stage of heating and tillering.
I lost 20 fps, drop from 77lb to 72 lb and an efficiency from 66% to 57% calculate.
Not so good but it's even in limbs :(
In future I can rasp away the sinew backing and take a look how the core is. If it's ok new sinew with more reflex can be put on. But I wait till I have made a new hornbow so I have a least one to shot with.

After some thinking, I could draw one inch more so I get back the 77lb but my test arrow is not long enough. So I had to make a new arrow with same mass. I got a inch more power stroke that way and need to make a new fd curve.

As long as the bow is not strung when hot, the performance should not suffer. Mustafa Kani clearly stated the bows are cooled off before stringing. From the picture if seems the transition between the kasan and sal in the right arm is a bit stiff. It is difficult to say what to do without seeing the bow un-strung, but maybe a little scraping there can reduce the width sufficienly for good balance. Depending how hot and stressed the bow became up untill now, it can be re-heated when unstrung to restore the power, at least in part.

Adam

I did not have the book when I did this :cry: I thought it was the hot material that give the flex so it could be safe draw on an unused bow. And leave it drawn school the bow.
With new fd-curve I got 61% efficiency at 25".
I have an inch defex now so I have to get more early draw weight.

Adam, at page 51 he wrote that the bow is first heated and then draw and it is left for cooling in hours.
I do the reflex again with hotter bow. I can see how the bow goes in reflex when I put it on my hot stove :)

The book by Klopsteg is not an exact translation - it is his interpretation. There is a drawing of another tillering stick in the original text by Kani, shown by Hein, but omitted by Klopsteg, who did not understand its function. It looks a little different and it serves to spread-out the tips of a reflexed bow to adjust the bending characteristics, correct twist etc. A similar tool is used by the Korean bowyer in the video by Thomas. I believe most of the heating and correcting (as in the book) was done with this tool, which will not cause as much stress in the sal sections of bow.

This tool, plus the tepeliks are essential for tillering, while the conventional tiller (as in your picture) is not, although it can be helpful in some cases.

Adam

Today I took the bow from its new heat treatment :)
And are back at 77lb but only 220fps. I shot with winter glove on so I can get few fps more.
So the method done my way balance the limbs but I lost 3% efficiency. It's so little so it can be from something else.
You see from the curve that it lacks early draw weight, but it probably because I have not put any reflex in it.
New horns are on way and next bow will get more reflex.
Experience costs :)
I have use 6" brace all the time. What would higher brace make?

Thinking bout that, 7 hour draw at tillering stick with no damage, Would a woodbow take that :lol:
Next competion against Tim I set up the rules.
Heat the bow and keep it at full draw for 2 hour, then crono :)

Thank you for your scientific experiments redhorse :lol: ! I never hade this courage -7 hours draw in tillering stick :roll: !

You are welcome, I hope this gives more to all of us beginners then colorful paintings would do. Times for that comes later :)

Yes, like you wrote.Mi object is no only good looking bow , or practice shooting bow , but full recovered secret old superb quality fast shooting - long distance composite bow .

I have been discussing the tillering stick or asa gezi with Edward McEwen and he suggested to me that Hein had misinterpreted Kani in just the way Adam mentioned. The tiller in Hein's illustrations is his own contribution. Most of his illustrations are drawn from Kani and appear also in von Hammer-Purgstall's article. However, you can see evidence of redrawing when you examine the figures and in the case of the tiller, there are two drawings one after the other and he clearly labels Kani's as wrong (Abb. 16b: "falsher"). Hein did not have the resources we do today and did not know about Korean practice.

But I would not be the first who read this and try if it work. And it did tiller. The bow is better in balance and is back to it's factory reflex.
There is other tings to discus also, like the owen and weight adjustment by shooting hot bow.

Redhorse, I think I understand your approach and wish you luck. As to me, I have always tried first to use the original technique and I do my best to understand it. I will then attempt modifications. In most cases however, the original methods are the most effective and rational.

Shooting a hot bow will obviously reduce the draw weight, as well as leaving the bow strung for a long time. The bow may still be ok and the efficiency may not drop too much. I leave my hunting bows strung for months at a time. But if one wants the bow to be fast, this can not be recommended. I bet many bows were badly degraded by the hot stringing method in the attempt to follow Klopsteg's translation.

Adam

As I understand the Kani method is for flightbows. With almost round reflex. In that case a hot shooting would not do so much harm as in a straight warbow. I you lose 2" reflex you have plenty left. But on a war bow you can get defelx.
And also, how much is the adjustment in lb? If its just few % it's not so much. But if is 10% or more maybe it would be better to make a lighter bow or rasp sinew and horn to lower the weight.

" I have always tried first to use the original technique and I do my best to understand it. "
I agree about that. And the understanding part in high light :) If we know why then we can make it even with other technique, as take the Koren tiller to Turkish bows.

No test with 7" brace. One ear broke at bracing. I have ears from an other broken bow so I splice in them.

It seems reasonable to assume that if you heat a composite bow and then brace it partially drawn on a tiller for hours as recommended in Klopsteg's translation of Hein, there would be some creep in the sinew layer. If you then reheat it, tie tepeliks to it and leave it drawn on the tiller, why would the bow remember the curves of the tepeliks?

I am curious because of the problems created if this is effective. I have braced Korean bows and one of Adam's bows while warm, corrected the curves, unbraced them and re-braced after cooling and have had the corrections still there. However, that is a long way from leaving them partially drawn as Klopsteg reported. Outside of this one translation, I can recall no account of leaving a bow drawn to set the curves. There are other accounts of leaving the bow braced to reduce its draw weight, some in Klopsteg.

Lots of people have read Klopsteg. It would be interesting see how many bowyers have tried this and what effect it had.

I am not skeptical of Redhorse's experiments, but I wonder whether it would work with every bow.

"why would the bow remember the curves of the tepeliks?"
Yes, why would it do that if it's not in the profile from beginning?

The confusion is a result of two things: 1. Klopsteg did not write where to heat the bow, 2. He completely disregarded the real tillering tool of the composite bowyers, so the reader can not know which tillering tool (the real one or the conventional western) was actueally used in these operation.

The bottom line is this. Heating and stressing the limbs in the sal sections, by the way of the tepelik or by drawing the strung bow, should be avoided, unless the draw weight reduction is desired. Heating and stressing the other sections, whichever way, can be done to correct the overal curvature, to achieve certain shooting characteristics and to eliminate twist. The treatment done on the sal sections will always degrade performance, done on the other sections may not, and may even improve it.

The amounts of stress and heat dictate which operation produces the permanent change for the bow. More heat, more stress, longer time caused more creep in the materials. All operations can be reversed for the most part by stressing the parts in the opposite way as in restoring the reflex.

Adam

So if i get this right the bow is heated and corrected unbraced with a kind of device that is not described in the book. If so is it possible that anyone has a picture or drawing of it, it would be interesting.

I have read the part of tillering the bow a couple of times and if to use that method Quote: After first adjustment it is warmed again,drawn to the next notch and again adjusted. end
When reading it its seems to me that the bow is drawn warm, I guess that one cant believe everything that is written, newspaper lie all the time :) I haven?t tried the method my self.

But when bracing a strong bow for the first time is it a wise thing to heat the sal sections and then open the bow on the tepeliks or should the opening be made with a cool bow? the later is how i have done.

This tipe of discusion was signifikant for high level our knowledges about real funtion composite bows . From this point is visible that all problem do not endit when you succesfully cuting, gluing and drying your bow. Live of this complicatid weapon only started and we must know about much more thinks .

Puzio, this "other device" has notches as well, so the bow can be "drawn" to the next notch etc.

There is no need to use heat on any bows and as you say the limbs can be opened with the tepeliks.

Adam

No picture on the device?
Well back in business again :)

Back to square one then. Best to build the bow with all peaces as equal ass possible. and a perfect alignment and not much correction is needed.

Here is a quote from Von Hammer-Purgstall on Kani's illustration translated by one of our ATARN colleagues:

Fig. 20:
A bow taken from the previous state to one in which it is held at both ends by a stick, in
order to make it used to this position.

Fig. 21:
When the bow has the stick removed, it has the form shown in fig. 20.

The implication is that the asa gezi was used to open out the reflex of the bow. When Hein redrew this illustration, he clearly drew the nocks on the belly side of the bow, suggesting the shooting nocks had not yet been cut. However, the original drawing is ambiguous and the description of the action suggest that the bow was ready to be strung.

Klopsteg points out several times that he did not believe that Hein understood Kani regarding archery technicalities. Klopsteg was a scientist and added a comment after the description of the process of drawing the bow on the tiller stating that:

The Turkish bowyer acts upon the principle that the bow acquires its elasticity by drawing, and its flexibility by warming.

His later technical comments on the physics of bow performance indicate that this quote was a tongue in cheek reference to Hein and Kani's ideas about how bows work.

The tillering device as pictured is extremely useful in adjusting the shape of the kasan sections and correcting for twist. It would normally be used in the initial stages of opening the bow, although sometimes is needed later as well. The use is described in my book in the chapter on tillering.

The sentence: "The Turkish bowyer acts upon the principle that the bow acquires its elasticity by drawing, and its flexibility by warming" is ambiguous due to the difficulties in translating (or rather interpreting) the original text. Both Hein and Klopsteg did not make composite bows and could not fully understand the meaning of what was written by Kani.

Adam

This explains a little, there is two sticks. One for the full draw tillering and one for the bend to brace.
Schooling the bow and fine tune.
I school my bow when it's still "green" and are easy to make the sinew to stretch to position. If the bow drys a year the heat way make sense.

?....... :D

An other way to make it.
Do you have data on the bow? F-d curve?

No, but its an example to use the asa gezi

It's very close to be a crab bow. Would you please make a fd-curve on it? It should have high early draw weight.

This si what i love in composite bows- heavy recurve - like kyudohund bow -and more.Your work is impresive , but little more reflex :D

Redhorse, I have to beg you for patience. After decoration the bow still is a bit sticky from varnishing. I will brace it again in spring and do the fd-curve.
When I braced it the first time to full draw, as you can see in the topic "turkish reflexbow", it was quite heavy, but I didn?t measure the drawweight. Sal-section in the middle-part is 12,5mm thick, including parchment-cover, colour and varnish.

Peter

Ok new ears are made and shot. One arrow on full draw 26" give 213 fps. So I lost a little speed again.
But I have 10 gram more wood on ears and still got 65% so it's not worse then before.
The ears have less angle, I lost 6lb weight but have a easier bow to shot.
With 7" brace the f-curve raise faster but follows the old one all way after that, but is lower all way. From 77 to 71. Because of the ear angle?

Update of latest rebuilds. I am at version 6 now.
V 5 was 11 gram more sinew and give some weight and some speed.
V 6 I thought I shot a little today, sun for first time in weeks. But I could not brace as easy as before????????
What I have done is remove 2 mm width and some more drying time.
So I made a fd-curve and got 86 lb at 25" belly. No wonder it was hard to brace, 10 lb more. It shot steady over 230 fps but still the efficiency is low :( Mass 364 gram. 1.14 x straight fd-curve. With 7" brace I guess I lose some weight but get easier accuracy.

Good news Redhorse. Impresive 230fps. :D

230 from 86 lb 370 grains is bad. But it can be made better :)
Today I file away 5 gram sinew at the corners and got 80 lb but with same or maybe even faster speed 235 today. The efficiency get up 5%.
If I can get 240 its ok, one 80 lb I had made 255 ones but steady over 240.
It seems that I will never get any finish and paint on this bow :)
It start to be unstable, a little twist occurs now.

You are re-reconstructor master. :lol: I havent this super fast nervs like you . If i made bad bow , next i am in depresion 3 -5 month and then i can start another- and very slowly... :roll:

I believe it better to make all faults in one bow :) so you don't have to do one in every bow you build :)

From this reason i work in one time in more bows. With diferent woods , horns, tendons,even glues. Litlle complikation foundings . :lol: Now its abou 10 bows... Mybe 1 was in future covered and painted :D

Fd-curve at 6" and 7". Speed fall from 235 to 231. Loaded energy from 70.42 to 66.34 ftlb.

Finally the bow is done :(
I got a broken limb just at the end of handle fade. But it did shot 210 fps anyway. And draw 70 lb, not bad from a broken limb bow :)