Different woods different styles

[Badger]

       Here in the modern world we have access to bow woods from all parts of the country and the world for that matter. Back in the primitive days a bow maker would likley only have access to a few woods. He would pick the ones that best suited his style or learn the styles that best fit the various woods he worked with depending on the job that he needed to get done. This is where I believe a lot of the problems come in when working with white woods. I don't believe for the most part we have perfected the styles around the woods we work with.

      We often compare fiber glass bows to primitive all wood bows. On the average a fiberglass bow will have about a 15% advanatage in power. The best wood bows will however shoot at comparable speeds to high end modern bows. This is good evidence that we are loosing out primarily because of design. Design means a lot more than just recurve or r/d or hill style. Design really implies on how we intend to use the wood to best accomodate the style bow we plan to build. Wood bows can be comparable to modern bows in mass weight and can even edge out modern bows in the mass dept so we can't claim thats where we loose the power. The power is lost through hysterisis which is simply internal friction, it is also lost through poor tillering and poor design.

     The old school of thought was that about 10% of our losses were due to hytrisis and that was just an unavoidable loss we had to deal with if we wanted to work with wood. As evidenced by the standout bows that can compete with modern bows hystrisis is more controllable than we have possibly thought it was. I did some tests a few years back that strongly indicated hystrisis really didn't play a part in the losses until the wood started breaking down. Thats where I came up with the no set tillering tecnique of monitoring the condition of the wood throughout the tillering process. The mass theory was also a product of this same series of tests.

      When it came time to write the chapter I really felt I was a few years away from really having as much information as I needed to be as difinitive as I would have liked to have been. I did feel it was useful none the less and went ahead and wrote the chapter being fully aware I still had considerable work to do. I tend to have an aversion to attention even though I do love talking bows and arrows, the undo attention I got form the chapter sent me crawing back in my cave and I slowed way down on my bow building and my testing came to a standstill. A couple of years ago I retired form work and decided to continue where I left off with my passion for bow building returning.

      I really didn't know exactly where to start, some of my equipment for testing had been dismantled and trashed or had become inoperative for one reason or another.  I just started building bows, one after another every style I could think of from every wood I could get my hands on. I really didn't have a clear direction as much as I was just trying to stimulate questions and puzzels that I felt needed to be answered. I was no longer building bows to a specific weight or draw length as much as I was just building them to see what I could get out of them stopping just at the point where they started to breakdown. Just going by feel I knew most of them were going to be between about 50 and 60#.  When I hit that point I would simply set the bow aside and start on another one with a slightly altered approach, never writing anything down of course. After a couple of hundred bows and a year or so went by I was starting to see patterns emerge. Regardless of design most of my bows were just starting to break down at around 23 to 24", and this is if I did my job and kept the tiller in ballance from the start, if I didn't they would start to breakdown sooner. I could still bring them all the way out to 28" with very respectable losses but they weren't perfect' they did have losses.

     After dunking my head in a bucket of ice water and holding it here till I almost drowned when I came up for air my head was clear and I suddenly knew the answer, we all know the answer but tend to deny it for whatever reason. I sat back and thought about all the successful bows I have seen in my life, the ones that really shine and stay shiny for a long long time. I thought about the little Tim Baker red oak bows that he would make week after week at the Pasadena meets that would shoot about 170 fps. A tad faster than his famous mojam bow that by todays standards would not garner any attention. These bows were 1 1/2 wide about 45 to 50# 68" long and slight bend through the handle. He had perfected that particular design with that particular wood. They were taking about 3/4 set just unstrung. I thought about the few r/d bows I had made that had approached 190 fps and seemed to maintain that level as long as they didn't get overdrawn. I thought about the Mark St Louis bows with high consitent performance even under high stressed difficult designs.  They all had one thing in common in that they were wide flat limbs where they needed to be wide. All of a sudden now I feel like I have a new direction to take and something I can actually start to narrow down.

      The first thing I decided was that a pyramid design wouldn't allow me the lattitude I needed in thickness adjustment so I opted for a modified version of the american flatbow. I make the bow wide and keep the limbs parallel till about 12" from the tip as I near final draw length I start increasing my taper further up the limb as needed.  The pleaseant surprise with these wide flat designs is that you really don't gain any mass to speak of as long as the wood is not breaking down. I was pleaseantly surprised as to how thin I could actually make the bows, My mass weight was staying about the same but the bows were much snappier and performed better. This strategy really pays off when working with very dry wood. I have always slightly rounded by bellies just because it makes the tools easier to use and didn't seem to hurt performance. Well from now on I will be making them as flat as I can maybe rounded by a 1/32" of an inch or so just to give my scraper something to bite into. The rate of taper I have been using is very similar to that of the English Longbows. It starts off almost imperceptable and gradually grows steeper as it nears the tip. Not a straight line like you might see on a pyramid.
   
    Be back in a bit I got interupted.

       

[Prignitzer bowman]

Hello Badger, how do you know when a bow is breaking down when you are tillering it? I am not trying to start a fight just wanted to know so that I can learn. Can you post a couple of detail pics of your bows and as you have far more experience as I do, do you have a favorite wood? Thank you for your thoughts

Peter

[Slackbunny]

Interesting so far. I'm looking forward to where you are going with this. I've got a roughed out HHB stave that I'm about to start work on, but I think I'll hold off until you've finished.

[Badger]

    Peter, its ok to disagree or even argue I enjoy good discussions. As far as how to tell when wood is breaking down. If you are trying to catch it real early in the process you can use your scale and your tiller tree. It might be a little harder for those that use the tree early on but it will still work. Once you have your bow floor tillered go ahead and put it on the tree, try to make it as perfect as possible before you bend it very far, in other words correct any flaws in the tiller as soon as you detect them instead of pulling a few more inches just to see what it look like.

    Ok, suppose you have your bow on the long string and you haven't pulled it past about 6" yet but you feel it is close to bracing and you want to go a little further as it looks about perfect. Lets say your string is hanging loose at about the 6" mark. Pull the bow to 8" and write down the weight. If it looks good at 8" go to 10", now go back to 8" and see if the weight has changed. Lets say you now have the bow braced Pull it maybe to 10" and write down the weight, that will be your benchmark, now pull it to 11, go back and check the weight at 10 now pull it to twelve go back and check it at 10" again. If you need to remove some wood recheck the weight at the furthest point you had pulled it so far and start the process over. Each time you pull it to a new draw length pull it several times before rechecking your weight at the last benchmark. If you find it starts to drop a little weight you need to try and find out where it is breaking down before proceeding. If it is breaking down evenly all over you need to lower your expectations for draw weight. If it is starting to break down in one spot only then look for a place on the limb that you cna get bending more. I like to leave it stiff out of the fades a few inches and as I need that wood for more bend I can go back to it to increase my draw length.

   If you have a straight limbed bow its easy, you unbrace the bow and set a straight edge on it looking for places where the straight edge starts to rock just slightly. Curvy d/r bows are not always as easy, I suppose you could trace the starting profile and then set the bow down against the pattern or just examine it real close looking for slight places that have taken set.

[Badger]

Interesting so far. I'm looking forward to where you are going with this. I've got a roughed out HHB stave that I'm about to start work on, but I think I'll hold off until you've finished.

  I am hoping Mark wades in here, he is really the expert at pulling off these designs with no damage to the wood. I think he just does it from experience but maybe he will share that with us.

[Prignitzer bowman]

Than you Badger, think I will have to rethink how I make a bow. I never thought about the wood breaking down at such low draw lengths. Interesting please carry on with your post.

Peter

[Don Case]

I don't know if it matters but is the breaking down on the compression side or the tension side?
Thanks
Don

[Aussie Yeoman]

Great article Badger. Entertaining reading.

A few years ago I was almost exclusively making bamboo backed bows from a select few of our Australian woods, mostly Ironbark and Spotted gum. I found these woods were sometimes tension weak, which is to say they could be described as brittle. However their set-taking properties were pretty good, and the stiffness was off the charts. I mean, it would leave Hickory for dead.

So the way to overcome the tension weakness is of course to put something more tension strong on the back.

So anyway after a few bows I settled on two designs. A longbow about 68-70" ntn, from which I could get  1.5 lb per mm of width at the handle. The other was a flatbow about 66-68" long, and increasingly the handle riser got thinner and thinner so that every ounce of wood was doing some work.

Funny thing is the limb width taper on these were very similar to each other, and quite similar to yours: for just over 3/4 of limb length they were almost parallel, tapering possibly to 4/5 of original width over that length. After that it would taper in convex bulges to narrow tips, that got narrower as more bows got made.

These bows got to be very fast. I didn't have a chrono at that point, but as you said above, they were performing similarly to a glass bow a friend would bring over to shoot of similar length/draw specs.

Lately I'm making Red Oak bows, and am finding a slightly modified pyramid design to be working really well. Mainly for economy of time, but the performance aint too bad either. Not modified much, just a little. I recently made one that drew 37lb @ 26", which shot 13gpp 139fps. Not mind blowing, but for the slightly shortened draw and heavier arrow, I think that's nothing to be ashamed of.

Keep it coming Badger, I'm eager to learn more.

[Badger]

  If you work with the same woods and a similar desing all the time it usually isn't really an issue, you get good at that partiuclar design. But when you start playing around with different white woods or designs that involve a lot more reflex for instance it's good to know how to monitor your progress. I have mostly stayed away from recurves and stuck with a lot of D/R designs. Recently I started playing with some recurves with several inches set back and quickly found out I needed to make them wider and keep them wider further down the limb. I was really surprised how thin I could get the limbs if they had no compression damage.

[Buckeye Guy]

Careful Steve you may end up with what i been saying for years now ! 
I need to go home and do some measuring, cause I don't , but I know some of my bows are not even 3/8 " thick at the 2/3s point of the working  limb were I start tapering the width !
And save the riser section to make up what you lose in something else, like a knot !

Have fun
We await your findings !!
Guy

[huisme]

I didn't plan it or anything, but my best bows came out of their staves like this. Wide and very flat bellied out until ten-twelve inches when it was roughed out, but I ended up fading the taper up the limb relatively evenly. Kept the inner limbs a little stiffer, made my recurves pull their own weight, forgot about draw weight to focus on tiller, toasted the BL strategically, eventually got the handles working juuust slightly, and finally decided I couldn't do more to the wood without hurting it. It hurt to see each one go as I've been lucky to pull such bows out of staves after only a little more than one year, but luck and a little pain are great teachers.

Of course, I just now put two and two together when I read your stuff 

Keep writing and I'll keep reading 

[Badger]

  buckeye, thats the funny thing, It aint nothing new at all. Just speaking for myself for some reason I just don't always go as wide as I need to go even though I know better.

[PatM]

I still think this is a modern innovation  for when we are trying to break speed records. I don't believe it had any basis in historical technique.
 Many old school books mention breaking a bow in and finding the balance between broken in and broken down has likely always been the best compromise.

[Badger]

      I just had one of those AHA!! moments. It has been driving me up a wall that these extra wide bows are comming in at significantly less than my own mass formula suggests. We always think of width as mass when we talk wood bows. I did a little bit of math a few minutes ago, as much as a high school drop out can do that is. It does appear that mathematicaly it works out that at a certain point extra width can and often does become more economical with mass.

      Maybe some of you math geeks can help me out on this.  oz.

  wide bow 58" long, 50#@26", 10" handle and fades, static recurves 4" behind handle, 13" total working limb, limbs mostly parallel with slight but progressive taper. Mass weight 18.5 oz.  Limb cross section .340X 1.562=.531sq unches
                                             Narrow bow, 19.5 oz          "      .420X  1.375=.577 sq inches

 Smaller overall area in the cross section of the wider bow. Mainly because of slight almost invisible wood damage.

[Marc St Louis]

The elasticity of the wood is what will determine how well a design will perform.  With an elastic wood you can modify any design to be more compact and this can translate into more performance and/or more durability.   Round belly, flat belly.  For me this depends a lot on the wood, the design and what I want from the bow.   My experience is that if you have an elastic wood you can keep the limbs narrow and have a slightly rounded belly for improved performance at the expense of durability.  It really all depends on what you want.  There are very few wood species that are reliable in what they will give you, HHB is one.  It doesn't matter too much where you cut HHB you can expect a given return from the wood, as long as it's a healthy tree.  Others, Elm, Ash, Maple, are variable, Elm being the worse of these.  From what I have seen of Osage and BL they also are variable.

Now mention of the tillering tree makes me want to put my 2 cents in.  I know they are safe but if you want to get the most out of your bow then pull it by hand during the tillering process.  Feeling what your bow does as it's being drawn back is important.  Also keeping the bow at full draw on the tree, or by hand, or with a T stick for more than 5 seconds is a waste especially when you have finished tillering your bow.  You don't shoot that way so why subject the bow to this?

We all have our own methods of laying out and tillering a bow out.  Some think it out, I think Steve falls into this category.  Personally I make bows more by feel.  There's not much point in my trying to explain how I do what I do since much of it is done by instinct.  There are certain things that are immutable, elasticity of a wood being of prime importance is one such thing.  Like many I like to keep the limb width of my bows close to the same from fades to about mid limb.  Intuitively I know that the extra mass I get from the wider limbs at that location won't make much difference in performance, if any, but will make a difference in how much set the bow will take.  Also wide limbs at those points will make very little difference in air resistance. 

Balancing the width of the limbs to the elasticity of the wood is where the fun begins