Asymmetrical bow- designs Vol.2 – in harmony with nature

The boughs of trees in Konary, Poland.
I guess there are a lot of "Golden Ratios" in this tree Image via Wikipedia

For an understanding of asymmetrical bow- designs I should add another thought of Michael Winkler, comparing the string of a bow to a string of a musical instrument. The point of the lowest vibration of a string is determined by the Golden Ratio. So a nocking point adjusted according to the Golden Ratio guarantees an optimum transfer of the energy stored in the drawn bow.

Choosing bow- staves for asymmetrical bows I had to realize that trees or brushes are growing more or less according to the Golden Ratio. Look at a tree and you´ll realize that branches are arranged in matching the Golden Ratio. Maybe I´m wrong, but I´ve found a lot of staves grown like that:

asymmetrical bow made of a hawthorn- branch

The lower shorter limb is the lower thicker part of the branch, at the handle there was a crotch, so I had to cut of another branch, the root of the cut- off is still to be seen. I worked this bow leaving it its natural growing as far as possible. It is always a good idea to locate the handle at a crotch cause there is no bending.

asymmetrical hawthorn bow- braced

With its humb in the upper longer limb this bow looks very rude, but somehow very stylish, its a beauty by nature.

drawing the asymmentrical hawthorn- bow at 23"

As usual hawthorn- bows are strong, cause of the staves´”snaky” growing, I had in mind to do a good tiller job first, but finally I made a 57lbs at 26″ bow, it is a real fast bow.

The upper limb of an asymmetrical bow is longer and so it weighs more than the lower limb. When you´re used to shot a bow with a so- called loose grip you´ll benefit of an asymmetrical bow.

shooting an asymmetrical bow with a loose grip

An asymmetrical bow tilts forward just after the release when shooting it with a loose grip( the bow is “clamped” by the index and the thumb). This is exactly what you´ve to learn in kyudo:

kyudo- just after release- image via wiki

Wow, this guy is shooting just more relaxed than me. I appreciate his body alignment very much, he knows how to release with both feet on the ground!

It´s quite interesting to look out for asymmetrical bow designs outside of Asia. Among the Native Americans the Hidatsa- tribe is actually retaining a slightly asymmetrical design, maybe this is another proof for the Native Americans having migrated via the Bering Strait, the Hidatsa asymmetrical bow- design has been researched by the  University of North Dakota. The historians found out that the ballistic trajectory of an arrow shot by an asymmetrical bow is more flat, this researching result is matching researchings of some Japanese Universities focused on yumi- bows. So it should be easier to hit the mark with an asymmetrical bow.

a f/d- curve is an exact copy of the drawing capablities of a bow

That´s a f/d curve of an asymmetrical bow: the curve is an exact copy of the draw of the bow. At the beginning of the draw you´ve to move both limbs, the curve is steeper, so the early draw is feeling stronger. The curve continues more flat before ending up a bit steeper. A f/d curve of a symmetrical longbow is much more constant. No humb! The space under the curve is the energy- storage of a bow, if there is a humb energy- storage is usual higher.

Asymmetrical bows are storing up to 115% of energy, but efficiency is anyway low. I´ve to check out this inadequacy.

The Canadian bowyer Patrick Menzies is assuming that asymmetrical selfbows have to be made very strong for to take full advantage of this design.

An asymmetrical bow- design is a great option for to take advantage of branches of hawthorn, blackthorn, spindlewood and alike woods.

Next volume is focused on samples of asymmetrical bows.

the Golden Ratio


Heat treating a bow Vol.3- heat in shape

Heat- treating is the most important way for to boost wooden bows, for to correct their shape or to heat in a small reflex,  slight recurves, a small amount of deflex. But there ar limits. Soft or open porous woods are more suitable for heat- treating than dense woods like osage orange or black locust. An eligible candidate is moutain maple, it is the wood of choice if you need a solid core for a hornbow, cause it is the wood with outstanding glueing capablities due to its open cell- charcter. Less bowyers know about the outstanding performance of heat- treated mountain maple- bows.

Recently I had been ordered to do a selfbow for a 12 years old girl,  she wanted  a bow of maple. Among my mountain maple- staves there was a small thin fitting strip of mountain maple. Cause it was cut from a small diameter- sapling, it was such high- crowned, that I had to decrown it first ( decrowning bow- staves will be a soon upcoming topic at bowXplosion). I cut the bows´  design, tillered it at a drawlength of 21″, drawweight was 12lbs, the  favored drawweight was about 20lbs. I decided to heat in a bit deflex in the center of the bow and to reflex the outer limbs for to get a  shape like the half of a hexagon. This is a very powerful bow- design ( bow- design and geometry will be another upcoming topic at bowXplosion in fall).

the setting for heat treating the mountain maple- bow
my daughter heat treating a hawthorn- bow- helping me for to get a pic
heat treating- go with full power very close to the bow´s belly

If there´s only a bit adjustment work , a small amount of deflex or reflex to do, heat treating every marked section for about 2 minutes will be enough. It depends, heat treating dense woods could take 30 minutes/limb.

If the heat treating wasn´t succesful repeat it. After a heat treating, I leave a bow clamped for 24h, than I brace it checking the tiller again, maybe there´s something to rasp. Finally a full draw will point out a result. If the bow will keep its heated in shape, you´ve got it.

the bow right after the heat treating
the bow braced- ready for some shots
the bow unbraced after the shots

The bow kept the heated in shape, the drawweight has increased from 12lbs to 21lbs.

Next volume is focused on heat- treating juniper and hawthorn and heat treating vs. steambending.

Asymmetrical bow- designs Vol.1- what´s harmony?

I´m somehow hooked on disharmonies, some chaos, ways out of the boring mainstream, checking news…………….

So I´ve had to met asymmetrical bow- designs heavily. I guess a lots of bowyers and archers know the traditional Japanese yumi bows, made of horizontally and vertically arranged strips of well- chosen bamboo. A delicious job to do, demanding a long apprenticeship and experience. Actually Japanese master- bowyers are highly reputated. The forerunner of the the yumi made of bamboo was a selfbow- made of a single piece of wood- the maruki- bow- done in an asymmetrical design too.

Nowadays the art of Kyudo is well known as a kind of shooting a bow- the yumi- bow- in a meditative way. Kyudo is a very important exercise of zen- buddhism. The yumi- bow is well known as the bow of the famous Samurai- warriors too.

I met asymmetrical bow- designs when I was ordered to reconstruct Scythian bows excavated in Siberia and posted on ancient Greek crockery. I had to think over the sense of  asymmetry in bow- designs, after a good deal of considerations I decided to ask my bowyer- collegues around the world. A bad surprise: heavily uninterested! During my research in Siberia I was faced to hundreds of cardboards full of bow- findings, about 60% of them are snatchings of asymmetrical bows. All done as 2 wood- laminated bows, the basic principle of construction of bows of the Siberian tribes.

The follow- up model of the Scythian laminated wooden bows(look for my olon kurin gol- article), the Scythian hornbow retained unchanged the asymmetrical shape. Up to date hornbows have been done the asymmetrical way more or less.

A closer look to the subject tells us very clearly, that a symmetrically made bow, transforms into an asymmetrical shape when drawn. Imagine: the handle is the center of the bow, grasp it,  the arrow is lying on the root of your index, just above center. That´s the reason why even the famous English longbows were done in a slight asymmetrically version, the lower limb of the bow is a bit shorter for to assure a real center- shot bow. The ” center- or off- center- shot- question ” is a hot topic among bowyers and archers. Reasons enough for to get the bottom of asymmetrical designs.

Anyway what is asymmetry? Being in disharmony? Could it be measured, even calculated? The ancient bows I studied don´t look at all to have been made in a somehow chaotic way. For get a proper working bow, no other way as to follow the growing of the wood.

I decided to ask some people I was sure to be able to hit the bull´s eye.

Finally it was James Harrod, the founder of the “originsnet”(look for the link at my blogroll), who showed me the way. I´ve asked him:……….did you think, that our ancestors have had a kind of asymmetrical mind……………at first he felt somehow dumb-folded, but he thought over my question and discussed the topic with a friend of him, the artist Michael Winkler, who was just preparing a book focused on the Golden Ratio.

That´s it! As a naked figure: 1.681… two quantities are in the Golden Ratio if the ratio of the sum of the quantities to the larger quantity is equal to the ratio of the larger quantity to the smaller quantity………got it? This is the epitome of esthetics and harmony and a basic principle in nature. Euklid and Fibonacci were the first mathematicians, who made the Golden Ratio public and attached a greater importance to it, finally Leonardo da Vinci came up with his famous drawing of the “Vitruvian Human”.

the Vitruvian human by Leonardo da Vinci(wikipedia)

asymmetry makes the world go round? A painting I did at the upper limb of an asymmetrical bow

1.61 becomes the base of my making of asymmetrical bows: the length of the upper longer limb divided by the length of the lower shorter limb.The base for to tiller the bow is the maximum gap between the string and the bow´s belly when braced: the gap at the upper limb divided by the gap at the lower limb. Tests with my first asymmetrical bows confirmed my assumptions, the asymmetrical bows made according to the Golden Ratio outperformed the others  “somehow” done asymmetrical bows.

An additional insight of James Harrod about this topic is the fact, that in martial arts the 3rd chakra is dedicated to the power of fighting. There ar 7 chakras, the 3rd chakra is placed at the navel, so the distance of the 3rd chakra to the 7th chakra divided by the distance of the 3rd chakra to the 1st chakra is again about 1.61. Even considered to be unscientific the teachings of the chakras are very worth to keep in mind in that case.

some asymmetrical bows- from r.: a snaky hawthorn-, an osage-, a splitted limb black locust-, a wide black locust-, an ash- bow

All done according to the Golden Ratio.

same bows braced- I´m still missing the string of the wide black- locust bow

Next volume is focused on staves and woods qualified for asymmetrical bows and on their performance.

How to splice bow- billets Vol.2- 1plus1plus1=1

When winter has just gone I usually check out the woods nearby searching for trees or thicker branches died by cold or the heavy weight of the snow. 2 years ago I came across a dead blackthorn- trunk with only 2″ in diameter, the straightest and clearest blackthorn I´ve ever met. Usually blackthorn is growing very snaky, laced with small knots and barbes.  But too short, from its bottom up to the first branching it measured 40″. As soon as I realized the staves shortness, I got the solution of the problem: split it lengthwise, w- splice the halves. Cause of the limited thickness of the stave I would end up with a bow measuring 1″ at most in thickness. To less for a non- bending handle section, at least 11/4″ are required. But for to get a 50- 60lbs flatbow with 62″ in length I would get by with one half of the split measuring 36″(62: 2 plus 5″ for the splice). So there was a piece remaining I needed to add at the belly- side for to get the handle thick enough.

split it or cut it with a saw- the offcut is for the handle

Usually I split a stave like this with a bandsaw, but I preferred to split this premium- blackthorn with the bandsaw for to avoid any risk. I w-spliced the halves according to the instructions of Vol.1 and added the xtra- piece.

w- spliced blackthorn- additional piece added- fadeout wrapped with linen

I´ve inked the add and the outlines of the splice. For security I´ve wrapped the fadeouts with linen. The bow is not ready yet, I´ll have to do some tiller- work, anyway I´ve done some shots, it feels like to be a very fast bow. I´ll update you.

How to splice bow- billets Vol.1- 1plus1=1

For sure you´ve to had come across several times the cleanest bow- stave ever: but it is to short!

Just lengthen it! It isn´t the delcious job you think. Every bow has a handle, this is usually the spot, where no tension or compression forces are working. I´m speaking of bows with an accentuated handle. It will not work on D- bows, D- bows have a working handle, this design will not accept a lengthwise splicing. F.e. English longbows, the famous Cherokee longbows, most warbows are D- bows. A typical candidate for a lengthwise splicing is any bow designed according to the American flatbow, handle in thickness and in width about 11/4″, in length about 5″, fading out into the limbs.  Too big for any bending. The most secure splice is the so- called w- splice, it is looking like the letter W.

The glueline is really big: 4 x 5″ x 11/4″ makes about 22″1/8 squareinches, that´s the power of the letter W.

Bow- stave dealers are offering billets, usually a very clean, knotfree piece of bow- wood, to short for a bow.  When harvesting wood I gather short pieces of bow- wood too, if you want to make a bow of clean wood, splicing is a great option. Choose the greatest best bow- staves you can find, even it they are to short, splice them. You can add a certain amount of reflex to a bow while glueing the splice accordingly. To compose a bow of different pieces of wood is known since a long time, even the Scythians have composed wooden bows by glueing together 12- 14 wooden pieces. Remember my report of making the olon kurin gol reconstructions. Remember the 2 wood bows of Siberia or Northern Europe.

So splicing 2 billets lengthwise is not that challenge. For a bow measuring about 65″ in length you need 2 billets measuring 37″ in length. 37″ is about 65″ divided by 2 plus 5″, the plus 5″ is the extra for the handle. Work out the running through growthring for the back of the bow.  Cut both billets the right length , work the handle as a perfect rectangle: 5″ in length, thickness and depth 11/4″. It is important to cut the rectangle accurately, otherwise you´ll end up with a twisted bow, and it makes the splicing really easy.

preparing a w- splice- the perfect rectangle

If the recangle is done at both billets, mark the w- splice as follows:

the w- splice- 5" in length- top: foot of one jag of the W is about 5/8"(1.5cm)in width- bottom: foot of one jag of the W is about 1/3"(1cm)

Draw the w- splice on a sheet of paper, glue it to the backsides of the rectangles, cut it with a handsaw or bandsaw. 22″ to cut perfectly along the marks in a right angle! Check the splice, fitting perfectly?  If the billets are sticking together, the ends or tips of the bow are matching? Did you work along the construction line? Correct it with a small file  or sandpaper.  Ready for to glue. If you´ve used a dense wood like osage, locust or mulberry, precoat the glueline with a thin solution of hide- glue ( water: glue = 4 : 1 at least)  several times, than go for the proper glueing.

glueing the w- splice red elder
w- spliced blackthorn(top) and red elder

Leave the spliced billets for at least 2 days.

Next volume is dealing with 1 plus 1 plus 1 = again 1