Friday, March 20, 2015

Hunting Bow Wood - A birds eye view

This morning, I noticed a song sparrow flitting about the ground. He was hopping about randomly or so it might appear at first look. I saw the sparrow pick up a piece of dry grass and then discard it. Aha! Shopping for nesting material this sparrow was. I watched a while longer while the sparrow skipped about the ground, his head swiveling from side to side, pausing to eye a particular piece of dry grass or small twig, some he added to a small but growing collection he kept in his bill.  Having exhausted the available materials of premium pieces or perhaps having reached a carrying limit for his bill, he took flight and disappeared around the corner of the house. Just a minute later I looked out the back door to see a pair of western scrub jays inspecting and testing medium size twigs from a small bush in the garden. They were snapping off from the bush favorable twigs and dropping them to the ground to be picked up several at a time. The spring-like weather has got the birds a build'n.
This collecting of nesting material includes quite a lot of careful looking. I don't think I had appreciated this aspect of bird nest building before, but now, as a seasoned bowyer who has harvested quite a bit of bow and arrow wood, I could see clearly the care in which the material was selected. Both the song sparrow and the scrub jays would tilt their heads, lean in, or even hop closer to a potential piece of home building material, and then, always a pause in their otherwise hurried movements before either picking it up or moving along in the search. Simply picking up a twig did not guarantee it would be brought back to the building site. After rapidly milling the twig over in the midpart of the beak, it was either discarded cleanly or kicked back into the stack of keepers at the back of its bill. Once they had a full load of material, they flew off with the calculated determination only a creature building its home seems to carry. To an outside viewer, the scene of a modern-day bowyer selecting his bow wood from a myriad of forest sticks, must appear to carry a bit of lunacy with it compared to the nest-building bird. I imagine though, that if we were able to jump back in time 10,000 years and view one of our ancestors selecting bow wood, in a time when a good bow held the importance of a good home, we might find a character whose demeanor is indistinguishable from that of the sparrow building its nest.

 Originally, watching these birds inspired me to write an article that provided how-to information on selecting your own bow wood. But as I start in on that task, I realize that there are so many variables when taking into account the tree species, local environment, desired bow design and the bowyer's experience, that it becomes an impossible task to provide any meaningful generalized instruction on the topic, so I will just throw out some basic things to consider if and when you decide to start cutting and curing your own bow wood.Keep in mind that the best way to learn is through experience.

Learning to identify your native and local invasive trees is a rewarding process. Books and apps are useful, but nothing beats following around a knowledgeable naturalist through the woods. A notepad is more useful than a camera here.

Learn where your target tree grows.  What habitat or other trees is it associated with? 

The moon phase matters. Humans have long recognized that wood cut in the dark phase of the moon is more stable in its seasoning. 

Not all wood is the same:

Some woods do not tolerating violation of the edge grain, such as osage, and must be split out, while others can tolerate a good deal of run off and so can be sawed straight out of a tree with slight twist to the grain.

Be mindful of your maul and ax when splitting, as the back is easily damaged by a wayward strike. Likewise, take care when trimming branches with a chainsaw from a trunk round. 

Some woods check very easily and others do not.

It always looks better in the woods. It pays to be very picky upfront, as the wood never looks as good once it is home and cleaned up.

Moisture needs to be lost, not too slow, but not too fast.
Wood in the round will dry too slowly.
Wood immediately reduced to bow dimensions after cutting will dry too quickly.
In dry conditions avoid exposing the wood to high airflow.  In damp conditions, good airflow is necessary.

The way the tree grows matters. A leaning tree has more tension strong wood on the upside and more compression strong wood on the downhill face. Generally, the tension side makes better bows.

Billet length sections of trunk are much easier to find than full length sections.

Wood boring insect larvae and fungi are your two biological enemies, oh and and teenage boys looking to stoke their bonfire.

Sometimes it is best to keep the bark on, and others it is best to remove the bark. Tree species and your local drying conditions determine whether the bark should be removed and back sealed or not.

Gawking at potential bow trees while driving on primary roadways is a real hazard. 

Searching for good bow trees s often easier during the winter months when the leaves are on the ground. Identifying trees can be difficult for the beginner when the leaves are missing, but it is much easier to see through the subcanopy in the winter. You can cover a lot more ground with your eyes this way.

A GPS unit is not necessary, try your skill at roaming the woods without navigation assistance. The nature of inspecting trees along your search makes landmarking natural and enjoyable.If you discover a good patch that you need to return to later, even years later, dont fret over your lack of flagging or GPS, good bow-wood patches and their precise location have a way of planting themselves in your memory.

Cutting bow wood with friends is fun and exciting. Cutting bow wood with family is rewarding and memorable. Cutting bow wood unaccompanied by anyone but the forest itself is mystical and enchanting.

The Jays leftovers after snapping the twigs off from the shrub above. A prudent bowyer does not bring everything he cuts home.

This is the sparrow's gathering grounds. A nice patch of varying tiny twigs. The surrounding lawn offered little in comparison to this patch the sparrow was searching. Patchy distribution is the norm when it comes to searching out bow wood. Finding the good patches is what it is all about.

Saturday, December 13, 2014

Fast Flight Strings and the Bowyer's Knot: a Solution from Japan

A while back, I wrote a blog post on the utility of the bowyer's knot in the bow making process. One important aspect I left out of that post was the importance of string material to the function of the boywer's knot.  The reliability of the bowyer's knot is dependent on the material of the string.  While the bowyer's knot, aka timber hitch, holds securely on the rawhide, hemp, linen, sinew, and even Dacron B50 (polyester) strings, it has a tendency to pull out when used on the modern low stretch string materials, such as Fast Flight (kevlar). This can be frustrating, as the low-stretch material is well-suited to the task of tillering, while material such as B-50 is not.  Anyone who has experienced making a long-string from B-50 only to have a reflexed bow of decent weight stretch all of the brace out of the string knows that there has to be a better material for tillering strings. Likewise, the bowyer who has a fast flight string slip its bowyer's knot while under tension on the tillering tree wants for a way to make it work. Well, it appears the solution comes from Japan and the practice of Kyud: Japanese Archery.

I had recently cut a very long stave of vine maple (Acer circinatum). It had very nice reflex that began to really show itself after sawing the mature vine maple trunk in half along its length. This reflex was balanced near a point favoring the lower limb. Its form immediately brought to mind the Yumi bows of Japanese Archery. The Yumi bow is traditionally constructed of a bamboo belly and back with a bamboo and mulberry laminated core, but the idea of making a vine maple self bow in the yumi form had captured my imagination. I started in on reaserching the finer details of the Yumi's construction, and that is when I stumbled upon the solution.

The Tsuru, or Yumi bow-string, incorporates an adjustable lower loop (Tsuruwa?) that struck me as simply a "double bowyer's knot". This simple variation on the handy western knot looked like it might be the ticket for utilizing the low-stretch Fast Flight string material in an adjustable tillering string. I have since given it some testing on Fast Flight Plus string material, and so far, the knot holds. This, in my opinion, is huge; to utilize an adjustable knot with the low-stretch kevlar based string materials, such as Fast Flight Plus, is to remove the fuss and finagling from tillering strings.  It is the small discoveries, such as this, that I find exciting enough to write a blog about. I hope the information is shared widely enough that green bowyer's everywhere will not have to experience the frustration of having an adjustable Fast Flight tillering string fail at the knot on them.

Figure 1.  A traditional Yumi bow shown here unstrung (top) and strung (bottom). Note the extreme amount of reflex and the handle position well below center.

The knot itself is quite basic. It is a simple modification on the well-known bowyer's knot (aka timber hitch). The tsuru knot differs only from the bowyer's knot in that it incorporates two wraps around the body of the string, as opposed to one in the bowyer's knot, hence the name "double bowyers knot". This doubling-up appears to be all that it is needed to make the knot hold on "slick" materials such as Fast Flight.

Figure 2.  The tsuru knot, an adjustable bow string knot from Japanese Archery, Kyudu. The solution to the bowyer's knot and issues of slippage with kevlar based string materials. 

 At this point, I have only tested it on a couple of bows and only one of the modern kevlar based string materials and that is Fast Flight Plus in a 12 strand (2 bundles of 6) string.  Based on the performance of the tsuru or "double bowyer's knot" with this material, my feeling is that this knot will hold on any of the variations of modern low-stretch string materials. If you find that not to be the case, please let me know in the comments.

Best of luck in bending wood this holiday season!
Echo Archery

Monday, December 9, 2013

The Virtues of a Dull Blade: Stave Debarking

Often times, a bowyer is faced with the task of removing bark from a stave in a manner that leaves the wood underneath pristine and unviolated.  Nicks, dings, scrapes and cuts are not wanted; we are talking about the integrity of a bow here! One simple way to accomplish this is to cut the wood in spring or early summer when the "sap is up". During this time, the vascular cambium is growing fast and is full of water, allowing the bark to be peeled off quite easily.  Leaving a wet and naked beautiful sapwood back, a perfect natural back to the eventual bow. This method of green bark peeling has its benefits and own unique considerations, but as far as removing the green bark, there really isn't anything to it, simply work up the edge and peel; it often comes off in one continuous sheet* but this post is about another method of removing bark, or really another task altogether, removing bark from a dried stave. By dry stave, I mean one that was cut and seasoned with the bark on.  This same bark that once would have peeled off with ease, becomes glued down fast and tight to the stave. There are various reasons why we end up with seasoned bark on staves, and I wont try to explain them here, instead we will stick to explaining how to remove this dried on bark while maintaining the bow's integrity and our own dignity. 

Removing bark from a green stave is easy.  Removing bark from a dry stave can be difficult, frustrating and potentially waste you a great deal of time in the form of a bow that eventually breaks.  But don't despair, there is a way to make debarking dry staves easy, enjoyable and re-assuring. As you might have guessed, this is where the dull blade comes in, specifically, the dull drawknife blade.  It is common knowledge in bowyer communities that a dull drawknife is a tool well-suited to the task of drawknifing.  I myself have known that a drawknife is what you use to debark staves for quite some time, but it wasn't until recently that I truly realized the importance of the dullness of the blade. Might sound a bit trivial, but what I have discovered for myself is that there is a great spectrum of "dull", just as there are various levels of sharpness, and for debarking a stave, the dullness makes all the difference.

In the past, I have used scrapers and dull drawknives to debark dry staves, but to no avail a little nick or cut would happen hear and there, usually around the tiny little bumps we call pin knots.  While these don't spell death to your bow by any means, they can add up in the bowyers mind and move him to back the bow with rawhide or overbuild the bow a bit.  Not the end of the world, but an overbuilt bow and a great performing bow are often at odds; and rawhide has its place, but using it as a safety net for any bow that has a few nicks and scrapes isn't very satisfying.

Using a scraper, such as a cabinet scraper works well enough to remove the bark, but it requires lots of force to be applied with the muscles of the wrist and hand. A scraper requires lots of passes to cover the radiused back of a crowned stave as the microplane edge of the scraper cuts through the bark and only pulls up bark where it contacts bark. A scraper does leave tiny nicks in the back, often at the bumps of pin knots. And a scraper requires frequent maintenance to keep a good edge. In short, the scraper is adequate but not ideal. I used the scraper often for the task of debarking even though it was tedious and time consuming because when I used a dull drawknife I simply butchered the back of a bow, destining it to be backed.  My failure was in the misunderstanding of "dull" drawknife.  I thought a dull drawknife was one you had used for a long time and was in need of a good sharpening. That type of draw-knife was too unwieldy; it would work great when used cautiously, but all it took was one bad move, one moment of inattention, and there I was, spitting into the pile of bark shavings cursing at the tool.  So maybe this dull drawknife wasn't dull enough.  I will try an older, much neglected drawknife, one that is pitted and nicked up from laying alongside other metal tools, one that is completely dull.  But this type of drawknife would require that I learn where the nicks are in the blade and avoid them as they would act as little gouges, leaving trails of minor grain tearing. And as dull as this neglected blade was, it was still capable of diving into the lumps and bumps on the back, requiring extra caution to be used.  In short, using a dull drawknife to debark a stave cleanly just wasn't working for me.

Finally, I had the Ah-Ha moment.  I recently took a day to resharpen a number of hand-tools. I was looking over a small collection of drawknives, quite satisfied with the freshly honed blades, when I thought, what if I put as much care into dulling the blade as I do for sharpening the blade.  So I grabbed a coarse stone, and with some excitement at the prospects, took the freshly sharpened drawknife to the stone and made several passes flipping the blade over and back, increasing the angle with successive passes.  Then moved to a finer stone and repeated, steepening the angle ever more. It goes rather quickly to dull a blade compared to sharpening, as you are not forming a burr, rather you are working to avoid forming a burr.  While it required little time, I gave it the attention and thought that I would give to sharpening a blade and was rewarded with an absolutely beautifully dulled blade. Not every woodworkers dream I know, but this was it, I knew it was the ticket to debarking before I ever touched it to a stave. And when I grabbed a stick of plum and started scrapping the bark, it was  everything I could have asked for and so much more.  Suddenly, I had the right tool for the job, and what a great feeling that is!

I have enjoyed debarking several more staves (including the cascara stave pictured below) since dulling this drawknife and was so excited about its effectiveness that I had to write this blog post.  I hope you find the joy of a properly dulled drawknife and making your own big discoveries in bow-making.

Thanks for playing along, Carson Brown at Echo Archery 

Debarking a Cascara (Rhamnus purshiana) stave with a finely dulled drawknife.  Note: Cascara bark  (Cascara Segrada:  'Sacred bark', Spanish) is a very effective laxative.  Collecting the inner-bark shavings in catch bucket. 

* Don't toss your bark! Fold into the shape of a quiver or strip it into sections and weave a basket, or add some to your home pharmacy!  Inner bark often contains the highest levels of alkaloids in a plant, some of which are harmful and some of which are extremely effective at treating ailments (most are either, depending on the dosage).  Do your research thoroughly before self-medicating with plant medicines.

Tuesday, August 13, 2013

William Tell

The story of William Tell as I knew it was of a couple of guys, having had a few beers, decided to attempt shooting an apple off the others head.  Maybe it was off in the woods just the two of them drunk about the campfire when they pulled off the stunt, or maybe a bit more dramatic possibly it happened in front of a terrified wife or family pleading to stop just as it was realized what daring shot was actually going to be attempted amongst the late night festivities.  This is the vague idea I have held about the famed William Tell.

The true story of William Tell:
  • It is the year 1307, the people of Switzerland are enduring an oppressive Austrian rule.  One day, the Austrian ruler decides to display his power by placing his hat upon a post in the Altdorf marketplace and forcing all Swiss that pass by to kneel before his hat. A man by the name of Wilhelm Tell refused to bow down to the rulers hat, and so was sentenced to death.  However, the Austrian duke had heard word of Tell's great marksmanship and so decided that it would be quite entertaining to put Tell's skill on display.  Tell was forced to shoot an apple placed on top his son's head from considerable distance.  He split the apple in two, without harm to his child.  This single arrow fired from Tells bow ignited a Swiss uprising that soon led to the country's independence from Austrian rule.  To this day, the yew tree (from which the bows of the day were made) is referred to as "Williams' tree" in Switzerland. 

Statue of Wilhelm Tell in Altdorf square, Switzerland

I learned of this true to life tale of William Tell tonight, while reading The Yew Tree, A Thousand Whispers, by Hal Hartzell, Jr. I don't' know exactly why, but in reading it I was nearly brought to tears. Maybe because it was too easy to imagine myself  in Tell's shoes looking into my son's eyes from a distance before focusing on the apple upon his head; Death and Freedom balanced on the loosing of an arrow.  Or Maybe it was the shock of learning that there was such meaning, such substance behind a Name I had heard many times, but had only simple images for, images of laughing drunken jackass daredevils, not a stoic father forced to place his son's life on the trueness of his aim, the rightness of his peoples freedom. It seems the bow and arrow have always been and always will be a symbol of Freedom, whether it be in the hand of Robin Hood, Katniss, or William Tell. The bow has often provided the spark for the fire that rises against oppressive rule.

Tuesday, May 7, 2013

Parable of the Arrow

Today, while lost on the web, I came across this old Buddhist parable referred to as the Parable of the Arrow.  I thought it was worth sharing here for two reasons. First, it happens to list some interesting details about the parts of the arrow used in Asia during the time of writing (?), including stork feather fletching, monkey sinew, cultivated arrow shafts, calf-toothed arrows, bamboo thread bow strings, and more. Second, the parable serves to illustrate the foolishness of spending ones life pondering the meaning of life. If only I had come across this parable back when I was in grad school stuck in a rut, toiling with the meaning of existence to point that existence itself seemed absurd. Without further ado, here it is, straight from Wikipedia:

"It's just as if a man were wounded with an arrow thickly smeared with poison. His friends & companions, kinsmen & relatives would provide him with a surgeon, and the man would say, 'I won't have this arrow removed until I know whether the man who wounded me was a noble warrior, a priest, a merchant, or a worker.' He would say, 'I won't have this arrow removed until I know the given name & clan name of the man who wounded me... until I know whether he was tall, medium, or short... until I know whether he was dark, ruddy-brown, or golden-colored... until I know his home village, town, or city... until I know whether the bow with which I was wounded was a long bow or a crossbow... until I know whether the bowstring with which I was wounded was fiber, bamboo threads, sinew, hemp, or bark... until I know whether the shaft with which I was wounded was wild or cultivated... until I know whether the feathers of the shaft with which I was wounded were those of a vulture, a stork, a hawk, a peacock, or another bird... until I know whether the shaft with which I was wounded was bound with the sinew of an ox, a water buffalo, a langur, or a monkey.' He would say, 'I won't have this arrow removed until I know whether the shaft with which I was wounded was that of a common arrow, a curved arrow, a barbed, a calf-toothed, or an oleander arrow.' The man would die and those things would still remain unknown to him."
Cula-Malunkyovada Sutta: The Shorter Instructions to Malunkya" (MN 63), Majjhima Nikaya
Thich Nhat Hanh comments on the way the parable of the poisoned arrow illustrates the Buddha's anti-metaphysical views:

            The Buddha always told his disciples not to waste their time and energy in metaphysical speculation.  Whenever he was asked a metaphysical question, he remained silent. Instead, he directed his disciples toward practical efforts. Questioned one day about the problem of the infinity of the world, the Buddha said, "Whether the world is finite or infinite, limited or unlimited, the problem of your liberation remains the same." Another time he said, "Suppose a man is struck by a poisoned arrow and the doctor wishes to take out the arrow immediately. Suppose the man does not want the arrow removed until he knows who shot it, his age, his parents, and why he shot it. What would happen? If he were to wait until all these questions have been answered, the man might die first." Life is so short. It must not be spent in endless metaphysical speculation that does not bring us any closer to the truth.
Hanh, Thich; Philip Kapleau (2005). Zen Keys. Three Leaves Press. p. 42.

Tuesday, April 30, 2013

How to tie the Bowyer's Knot, aka Timber Hitch

UPDATE (12-13-14): Check out the latest blog post discussing Fast Flight string material and bowyering and an ancient adjustable knot from Japanese Archery.

This is a short how-to on tying the Bowyer's Knot. Also known as the Timber hitch, the bowyer's knot is an incredibly useful knot and is one of the easier knots to learn.  For the bowyer, this namesake knot is used to form a bowstring loop that can be quickly undone and retied to change the length of a bow string.  This is particularly useful during the tillering process when you start checking the bend of your bow with a long string  and progressively shorten the string during the tillering process until a full brace height is achieved   In addition to its use on the tillering string, the bowyer's knot can also be used on a finished bow string, typically forming the nock loop at one end of the string, while the other nock loop is formed by either a bowline knot or Flemish twist loop.  Using the bowyer's knot on a finished string is not a common practice these days, but I find it handy for making a quick string for a kids bow, or for natural materials strings such as rawhide or sinew, where humidity can affect the length of the string requiring slight adjustments. This is the same knot used by luthiers to secure guitar strings to the bridge.

As a bowyer you will find this knot to be indispensable.  It acts as a secure slip knot that is easily loosened and undone or adjusted.  It is a great utility knot with many other uses beyond bows and guitars. Making predictable adjustments to the length of your string with this knot comes with experience, but tying the knot itself and adjusting it are easy enough that the beginner has no problem achieving the proper string length with a little trial and error. 

Tying the Bowyer's Knot

Take the end of your string and form a loop

Take the end of your string and lay it back over itself, passing it through the loop

Repeat step 2 for 3-4 times, and your knot is complete

Here are several illustrations of the completed bowyer's knot:

Hope that you found this useful.  If you enjoyed the content, please consider subscribing to my blog.
Carson Brown
Echo Archery

Thursday, November 29, 2012

Heat Tempering a Bow over Hot Coals

Coals of douglas fir; the scraps from Surewood Shafts arrow shaft production
Last night, I heat tempered an ocean spray (Holodiscus discolor) bow over hot coals.  This is the first bow that I have experimented with heat tempering on.  The process itself is really enjoyable.  It is reminiscent of attempting to slow-roast a marshmallow to perfection.  I built the fire simply for the purpose of tempering, or heat-treating as the process is also known.  The scrap pieces of Douglas-fir I had on hand ended up being ideal for getting a hot bed of coals established in no time at all.  I know that a lot of bowyers heat-temper bow limbs using an electric heat gun, and while the heat gun I have is capable of doing the work, I can't see it doing the job nearly as well as this bed of hot coals.  My fire pit is not very big, just large enough to do one limb at a time, and so the coals need to be stirred and built up between treating each limb. Even then, the treating itself was less than 10 minutes a limb.  This particular ocean spray bow was not the most ideal candidate for heat-treating as it has a pithy center, and where this pith ran just under the surface of the limb's belly, a fissure would begin to open up during the heating.  While these fissures are quite noticeable, they should only pose comsetic issues and some minor tiller touch up. While Marc St. Louis, Canadian bowyer that is expert in heat tempering, recommends avoiding such pithy centered sapling staves, I couldn't resist after reading that natives of the northwest would use fire-hardened ocean spray for everything from clam-digging tools to wooden nails. The wood has definitely hardened from the tempering process. I used a cabinet scraper to thin the limb tips a touch and found the wood to feel very dense.  Also, it now has a very pleasant aroma.  One step worth mentioning in the process that might differ from others is the use of shellac as a sealer on the bow prior to heat-treating.  I applied several thin coats of shellac (fresh blonde shellac flakes dissolved in denatured alcohol) followed by several more thick coats. Shellac is reported to plasticize under high heat.  My thoughts are that the thin cut of shellac will penetrate into the wood pores, and then during heat-treating will plasticize, possibly even binding with the lignan. If not it should still function to regulate the loss and re-gain of moisture during and after the heat-treating process. By the way, shellac is a really interesting and versatile natural material produced from the shellac bug.  If you are interested in learning more on shellac, check out Vijay Velji's video, where he travels to India to learn about shellac. I am looking forward to stringing and drawing on the bow to feel the effects of the tempering, but that will have to wait as the bow will need to rest in the garage and come to a stable moisture content after the heating session.