Primitive Archer
Main Discussion Area => Bows => Topic started by: dragonman on November 25, 2012, 11:24:37 am
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Did you know that when the grain of the wood runs vertically through the limb of a bow, the wood is stronger and more consistent than horizontal grain orientation? Differences in yearly growth rings are averaged out and the limb becomes more uniform than a limb with horizontal grain.
I was reading about experiments with early fibreglass and wood composite skis, which are made in the same way as bows and the wooden core was always made with vertical grain for added strength. The same technique is used in the core of japanese yumi bows too. My own experiments with ash self bows also agree. Vertical grain limbs take less set and pose less tillering problems, than bows with horizontal growth rings.
what do you guys think about this???
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Tim Baker in one of the TBB's wrote about this. Not sure he said it was stronger, just that it matched a flat ring orientation strength wise. Would be interesting to see data.
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All fine and dandy if you have big diameter logs and a saw mill >:D
But remember this is Primitive Archer, right?
Although to be fair it's the sort of thing I may try for a crossbow prod from some of my Yew offcuts, but I'm hardly gaing to saw up a Yew log to get it quartersawn and then have to laminate the sapwood back onto it... or am I??? ::)
Del
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There are all kinds of pluses and minuses making bows from edge grain or flat grain wood.Edge grain should always be more consistent the way I've seen it,but then a backing is needed in most cases.That's why your FG bow makers use that so much in there bows with their see through glass backing.Flat grain follows that ring on the back,and the grain feathers out on the belly.If both are tillered correctly to me there is not much diff in strength or durability.To me it's just a personal choice.Edge grain laminations to me opens up the power tools door with your drum sanders for thickness tapers etc.
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With ash bows, they never need backing with vertical grain in the limbs. It doesnt appear to make the back vunerable. cant see why it would be different with other woods that can be used for self bows...In fact , look at Half Eyes bows, they where always edge grain and usually not backed, he used many woods this way successfully
Del, have you heard of splitting?...,you need a hammer and a wedge, maybe an axe?...cant get more primitive than that.. >:D actually even a handsaw is less primitive
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Yes I agree about clean ash or other clean grained woods,but if you got knots on the back like hedge,mulberry,or any wood with knots a backing is the safest IMHO.
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Of course, Dragonman. I'm glad you brought this up. That's why the bowyer should ALWAYS follow the vertical or lateral grain when laying out a bow from logs EVEN if the staves were band sawed out of the log. If split the lateral grain will be followed. When making board bows the ideal is the have that lateral grain straight from tip to tip. If the board was milled at a left or right angle leave it there if severe. If the board was milled at an up or down angle, you'll also see the run off on the face and edge grain. Always that lateral grain should be followed. If you've built a bow from a small sapling you've followed that lateral grain automatically. The size of the log doesn't mean anything in that regard nor does whether you are looking at boards.Perhaps people don't know what the lateral grain is. There's much more on my site which shows the lateral grain. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/layout.html
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George, thanks for the link to your website, I havent checked it out before. Lots of good info there, I've bookmarked it to read it all later.
Yes I think this important. Even with fairly small logs you can stil split them so that the vertical grain lines run from tip to tip along the back of the bow. Since I've been doing this, I find that the bows are much less prone to having one limb bend differently to the other. If I really pay attention to symetry, they often come aout almost tillered after the first stringing....which is ideal.
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Interesting.
Is edge grained wood, lets take Black Locust for example, less suspected to crysalling? Is it faster?
Leo
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Leo ,the only difference in performance would be that the same mass of wood ,would be slightly stiffer, so possibly very slightly faster... but it wont stop it crysalling
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Thanks, dragonman. Has nothing to do with the wood. Whatever the wood is that lateral grain has to be followed, SlimBob. BTW if you split out your staves from a log as opposed to band sawing them out, you have automatically followed that lateral grain. The term flat grained or plain sawn, bias grain or rift sawn, or 1/4 sawn or edge grained refer to the type of the board cut that you can find at a lumberyard. They'll all make bows provided that lateral or vertical grain is straight tip to tip. Jawge
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How did I get dragged into this???? ??? O:)
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Hello guys!
I came across this old thread and found it really interesting. So I dig it out with a question:
I‘d like to use a small ash log, split it in half and use the splitting surface (the side that is normally used as belly) for the back. The fibers would be intact, just as with a chased ring at least from what I understand.
I can see some advantages here: Wide limbs can be produced even from small logs, because there is no high crown. The cross section is rectanguar and it accelerates the roughing out.
Has anybody expiriences with this? If it works, why is this technique not as common as chasing a ring?
Thanks!
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Just made an edge grain Black Locust bow out of a questionable piece of wood for a bow.The growth rings were paper thin.So instead of chasing a ring I made it edge grain. It worked fine, but had some horizontal knots running the width of bow on the back.I shot it for about 30 shots that way, and it held up.Opinion on primitive said it was dangerous. Really liked the way it shot so I backed it, and wrapped the knots.Still shooting.I have also made hickory bows from clean one, and a half by one and half inch Amish wagon wheel blanks that are doing fine.Sudbury design.If the blank has thin growth rings I think edge grain is the way to go with certain woods that are knot free blanks.JMHO
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The identical piece of wood -
Vertical Grain favors compression tension
Horizontal Grain favors elastic tension
(. . . pick your poison . . . )
regards,
John
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John , makes sense. Good info.
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Thanks for your replies!
So for ash, edge grain is a good choice, if I get you right.
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In theory maybe,,but for Osage and other twisty woods,,,I don't know if there would be an advantage,,, )P(
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Vertical and horizontal grain?? Which is which and how did he come up with those names?
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DC -
Example of vertical & horizontal grain wood . . .
(and to complicate things further . . . well you get the picture ! )
regards,
Scyth
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I saw some test with some guys spine type testing thread some where, I tried to look but didn't find it , I have used both and generally I figure about 2 lb difference in draw weight for the same thickness limb using edge grain ,but it always boils down to the quality of wood used ,I would take flat sawn wood with no run out vs edge grain with run out , it's very hard to get perfect edged grain wood with white woods and not as economical as flat sawn , I think the choice becomes even less important when used as a core or on a backed bow !
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Quarter sawn or edge grain tolerates no run outs while rift (bias) and plane or flat sawn will tolerate a few for a 50# bow.
Jawge
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On a stave,,,I prefer to follow a ring
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DC -
Example of vertical & horizontal grain wood . . .
(and to complicate things further . . . well you get the picture ! )
regards,
Scyth
So which is vertical and which is horizontal? Nothing in the pictures uses those words.
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That shouldn't be too hard to figure out if you stare at the pic for a minute.
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Thanks Pat. I was confused because I hold my boards on edge ;D ;D
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Then your horizontal,,,would be vertical,.. >:D
If u follow a ring,,,,your bow is less likely break...the edge grain may be stronger,,,but it may not be as durable,,,,that's why most stave bows are not oriented like that,,..it works good for a board stave,,,when designed properly,,..I have no scientific,,,proof,,,,,just my opinion ,,..
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Thanks for your replies. I think I‘m gonna give it a try!
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Wooden bats are less prone to break if the ball is hit so the edge grain is oriented to strike the ball. This is why the label for the bat is placed across the flat grain of the bat, and the correct way to hit is with the label pointed up. So this would tend to favor better strength and less sensitivity to grain disruption for edge grain Vs. flat grain.
I am not a prolific self bow builder. All mine are made from boards and I always went with edge grain. I’m sure there is much published data for this, since these kinds of details are important for using wood to build everything from aeroplanes to houses.
Another comment, a spine test will give an indication of the stiffness of the material, but the strength of a material is a completely different property. Sometimes the stiffness and strength of a material seem to be related, but this isn’t necessarily always the case.
Alan
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The reason edge grain, or even the less heard of "flipped grain" that was mentioned, isn't used could either be because it is difficult to do, not as strong, or likely just not tradition. I think you will find that a lot of people just do what has been done assuming it's for a good reason. Maybe it is or maybe it isn't. At least it works, which is the safe bet, but I don't think it's good enough to take tradition at face value. Blindly following dogma leads to no progress it just produces the same results we have, which may be enough for some people.
I'm going into the medical profession, and it is amazing to see the progress that was made once people started using research, and basing their medical practice on evidence. It's possible that in trying new things you will find they don't work that well, but maybe you could find it works better. I personally would like to see people, myself included, try new things and report their findings rather than just speculating that it probably wouldn't work, just because it isn't traditionally done.
(https://lh3.googleusercontent.com/uRiTSK3KC466kpWSJ8FvzvlyxHGboXUwIh0Gh-_W33dM2O9sfnIUWgm4mtYZ7QE243iObrr_WaeVK1LS3mGhI9vSpJk6XooLGEd7Eh0JwZ90eBVhKA_mB6PxuYYQXUZ6CieSLheY3LBlbU8CLa1ql36fyc4Qr5UZMYu1U5c1UR9aBuJyfwe7wWw8yFhP714MoC9Kd8Rz1blLrho8p5BUXQS-ydIJCnTeYPQLLk6w1iCjPyrJ6OH4mjYcrbG8yznxdE0WblccV7GHn3ZznFfXOgAlxBu193sZlUH9tDdF6AYCbpM0xDAeaXgaxyn64-C8qES3gShZOtmzwCWITwmGg9LIpweUctYlMgpM8oQFlrgePythM_WsjUq-CAATSliUNaBJcqXLcy5dT_yesDyxpUOj1EEQlZK3EzEYy2nHwwDoFD_oqL8AkvSuWMHj7btIUqrft6Nyx6sctaSMSaTAI5Q0nCULKOuqSCBEiIrL4asxtrl6bIhrvRLG21YuWPf6S2CSsr8Rp-ide8zXWc0JVsTKZRaE1nSC1fFev9QOGKmSV-THnnIEU0WXXXH7nMCBOtLCgGCKeJDB6rnTnpzdCp9_OglYdAVJJGHtS2ME31H2gXMmA1Bbz0FtXmjFx10m3HQRdX5DBtxj-6OpI_NfqIwAIhuh-wV5n0TQAzj97n_dNXb5n8uidUmbzqWRLwqGk4q46uHl81XvyHCn52c=w571-h519-no)
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Hello guys!
I came across this old thread and found it really interesting. So I dig it out with a question:
I‘d like to use a small ash log, split it in half and use the splitting surface (the side that is normally used as belly) for the back. The fibers would be intact, just as with a chased ring at least from what I understand.
I can see some advantages here: Wide limbs can be produced even from small logs, because there is no high crown. The cross section is rectanguar and it accelerates the roughing out.
Has anybody expiriences with this? If it works, why is this technique not as common as chasing a ring?
Thanks!
I had this idea of a "flipped grain" bow too, I started a thread about it not too long ago but didn't get very many responses http://www.primitivearcher.com/smf/index.php/topic,63538.msg892830.html#msg892830. I think I'm going to attempt it at some point in the future. I currently have 3 bows I currently have in the works before I can start another one from scratch, and as is, it's taking me a long time to get any done with my school schedule.
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I think things are done traditionaly for comon sense reasons & survival , I think we think we are smarter then we really are most things in bowyering have all been done before , edge grain wood if unbacked is a lot more susceptible to moister penetration then a ring followed , put stain on both & easy to see , but really only one way to find out build the bows to compare as far as performance & durability ! Its easy to speculate but really only one way to find out !
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Sure it can be done, as there's a lot of unbacked board bows to prove this.
But when using unbacked edge grain as a stave the early growth fibers are now exposed to tension. I have't tested this, but my guess is that those fibers aren't nearly as strong or durable as late growth ones, and a traditional stave has all unblemished late growth fibers.
I tend to agree with you Ritchie. Use your previous experience, history, tradition, advice from others as a starting point. From there the only way to prove something is to let the shaving fly. :BB
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I think things are done traditionaly for comon sense reasons & survival , I think we think we are smarter then we really are most things in bowyering have all been done before , edge grain wood if unbacked is a lot more susceptible to moister penetration then a ring followed , put stain on both & easy to see , but really only one way to find out build the bows to compare as far as performance & durability ! Its easy to speculate but really only one way to find out !
I'm definitely not saying throw tradition out the window, and disregard the expert advice from experienced members. I tend to be hard-headed with my ideas and get myself into trouble, but that's just the way I am I guess. I tend to have to learn things the hard way. I also think I should caution any beginner to go out and do "new" things when they haven't even done things the way they've always been done. Trust me I've done that too, only to fail. I am definitely no expert, I don't have near the experience of even an average member let alone the experts. However, I do think we shouldn't dismiss things so easily without first giving it a thorough, persistent, and honest try. I guess I'm trying to appeal more to the experienced members on this page. How many bows have you made now? hundreds if not more? Why not try something new, sure you may end up failing, but you might find out an alternative, if not a better way of doing things. Maybe you deem it not worth your time, and I guess that's your decision. I guess I find interest in different aspects of creativity than most and like to try to think outside the box.
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I think the edge grain bows prove,,,there is no performance advantage,..I'm pretty sure the world record setting bows Badger makes are not edge grain orientation,,,I hope he will chime in,..I am not talking laminated bows,,,and have nothing against edge grain,,,and have made them.,,I think both orientations can make a fine bow
I started making edge grain bows bout 30 years ago...as most of the older guys did,,,,it will make a nice shooting bow
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"I guess I'm trying to appeal more to the experienced members on this page. How many bows have you made now? hundreds if not more? Why not try something new, sure you may end up failing, but you might find out an alternative, if not a better way of doing things. Maybe you deem it not worth your time, and I guess that's your decision. I guess I find interest in different aspects of creativity than most and like to try to think outside the box."
You really think the guys building 100's of bows aren't trying new things? ....and vertical grain vs horizontal grain isn't thinking outside the box. It's done all the time!
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There is a lot of wood, hay, stubble and used hay in this and most threads.
Here is the absolute indisputable truth about edge grain and flat grain. I will not condense or summarize the material, because some would certainly say I misrepresented it.
https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch04.pdf (https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch04.pdf)
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There's about two sentences in that which sum it all up to a conclusion most wouldn't be surprised about.
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ok I tried to read it,, whew,, what I got was that in some species,, the grain orintation makes no difference,, and in some it does,, (S)
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ok I tried to read it,, whew,, what I got was that in some species,, the grain orintation makes no difference,, and in some it does,, (S)
OKaaaaaay.
Lime is tangential, red is radial. Bigger number = more strength.
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"In some species, there is no difference in 0° [edge grain] and 90° [parallel grain] orientation properties. Other
species exhibit slightly higher shear parallel or tension perpendicular-to-grain properties for the 0° orientation than for
the 90° orientation; the converse is true for about an equal number of species."
is probably the most significant statement in the article about what we're discussing.
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Here is the absolute indisputable truth about edge grain and flat grain. I will not condense or summarize the material, because some would certainly say I misrepresented it.
Sounds like you may have in your next post. Or at least made a biased selection.
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PatM,, you still can't :D prove scientificly that Elvis was not a good singer,, :) :D
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ok I tried to read it,, whew,, what I got was that in some species,, the grain orintation makes no difference,, and in some it does,, (S)
OKaaaaaay.
Lime is tangential, red is radial. Bigger number = more strength.
Modulus of elasticity does not equate to strength per se. Rather it's just a measure of how stiff it is. Yew has a lower modulus of elasticity than red oak, yet I think we could all agree which is the better bow wood.
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The answer may be to use some woods vertically and some horizontally but not generalize them all. I'm certainly never going to mill a perfect Elm tree into edge grained boards ,
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Again I repeat . . .
“The identical piece of wood -
Vertical Grain favors compression tension
Horizontal Grain favors elastic tension
(. . . pick your poison . . . )”
regards,
John
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In one of my early bows I built a Osage bow I think 68" or so. The stave was not very wide. I managed to get 7/8 inch limbs to mid limb. The bow limbs almost sq. Surprisingly the bow took very little set. The bow had excellent cast. My mistake was not following the grain and the bow kept splintering. I liked the cast and put two or three patches on. One of those you just don't want to give up on. Happens a lot in early builds for some of us! Any others out their have the same results. Most 1-1/4 bows I build today take more set. Maybe I need to try another one 7/8 wide. Arvin
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what was the draw weight of the narrow bow,,
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I think I can summarize, that nobody said my plan wouldn't work.
So I just give it a shot. Me feeling tells me, that ash is a perfect candidate for this. My opinion is that ash is good in tension and bad in compression, so the wood can benefit from the vertical orientation. In addition ash splits nicely, even the logs small in diameter.
I hope I get around tuit this week. Otherwise I'll try it next week.
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As noted there is nothing new or revolutionary about this idea. It has been done thousands of years ago and is still done today. As to why it's not done as a simple solution it's likely because wood tends to have grown over defects closer to the core. A perfect exterior stave can be a mess near the center but had plenty of time to grow over.
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I think the edge grain bows prove,,,there is no performance advantage,..I'm pretty sure the world record setting bows Badger makes are not edge grain orientation
Just because the world record bow isn't edged grain is no proof that edge grain bows couldn't be made to be world record setters some day. I'm not trying to argue that edged grain is superior to parallel grain, just that it shouldn't be dismissed. I don't know how badger feels about edge grain, I'm sure he has done it before. I would venture to guess that the majority of his bows aren't edged grain for whatever reason. In fact, the majority of all bows aren't edged grain (I've seen maybe two or three posted on here, and I haven't seen a non-board-bow self-bow yet). Therefore the ratio of them to parallel grain bows is pretty low. It's hard to make world record setters when they just simply aren't being made in general. Even the best bowyers can't perfectly reproduce those highest quality bows, even if they use the same wood, design, and skill while making them. You have to make enough to "stumble" upon that really fast shooter. I would argue that edge grained bows just aren't made enough to 1) discover/"stumble across" those real shooters, and 2) have the repetition to perfect the process of making them (as I'm sure they preferred to be worked differently in some ways than parallel grained bows). Although it's not a self-bow, or a world record setter, DC made a very good edge grain bow not to long ago shooting in the 190 fps at 10 gpp http://www.primitivearcher.com/smf/index.php/topic,63436.0.html. If anything that should prove they can be as effective as some of the best parallel grained bows.
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You really think the guys building 100's of bows aren't trying new things? ....and vertical grain vs horizontal grain isn't thinking outside the box. It's done all the time!
I never said they haven't been made by the experienced members. I actually wasn't thinking specifically of edge grain when I wrote that, more of a flipped grain bows, or other radical designs and materials. However, I would say that edged grain bows aren't made that often, especially self-harvested/dimensioned self-bows. Of the hundred of bows experienced bowyers have made, how many are edge grain? Of all the bows that are made by everyone, how many are edge grain? I was trying to address the issue of why many aren't made, not that they never have been made. PatM suggests that it is probably due to practical reasons, with imperfections requiring larger diameter trees. And maybe that's the reason why. Having never made one myself I can't really say one way or another based on experience, it just seemed to me that it also has a lot to do with tradition. That was my point.
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I made one edge grain yew backed with edge grain maple. It worked well, actually it was my best bow up til then. The reason I did it was that the billet, if used conventionally, would have had a big sideways bend. I decided to turn it sideways and split it. I got a pair of sister billets that used edge grain was already nicely reflexed. I've since built very similar bows from plain sawn yew with edge grain maple backing that were a few fps faster. If I found another piece of wood with a sideways bend like that I would do the same thing again but I don't think there is much in it for speed. Maybe the fact that it was backed negated any edge grain advantage.
I think using your stave inside out will work, no doubt about that, but you will have a concave back unless it was a big tree.
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Again I repeat . . .
“The identical piece of wood -
Vertical Grain favors compression tension
Horizontal Grain favors elastic tension
(. . . pick your poison . . . )”
Just for the preservation of the language, I think you are confusing the word "tension" with stress.
"compression tension" is an oxymoron.
regards,
John
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it mostly has a lot to do with experience,, (--) most of my bows are self bows or rawhide backed,, guys using other backings may have different thoughts about it,,for sure,, (-_)
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Jim D. -
Nota bene :
On May 21, 2014 at 3:00 a.m. I had an unexpected stroke : my left carotid artery was completely blocked and no surgically (or otherwise) intervention was possible. I was 64 years of age.
I had to learn how to feed myself & to walk & to talk & to write, etc..
The struggle continues to reprogram my neural context . . .
& reading and writing to this day.
regards,
Scyth
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there are some apple vs orange type comparisions being made that might be confusing this discussion.
a stave with a latewood natural back or a properly chased ring puts the most dense and strongest wood where the strain is the highest, and most will agree this is the best way to make a bow. But lets compare boards sawn the two different ways.
With a board, a flat grain surface of latewood may in fact not be as thick in some places as others, and the closely underlying early wood may be asked to handle more strain than it is capable of. An underlying imperfection in the earlywood may also be a hidden point of stress concentration.
With a board of vertical grain, the most highly strained surface consists of latewood from each ring. Even thought the earlywood is also present in alternating bands across the most highly strained surfaces, The integretiy of the wood is being averaged between the dense and less dense, and a flaw in the weaker early wood is less likely to cause a splinter lifting on the back
In effect, (if there is no runout of the vertical grain), it offers a more consistent materiel to work with, and may appear to be stronger than the same piece of wood in a flat grain orientation, unless adequate dense latewood thickness can be maintained on the both the back and the belly. Of course if your limb tapers in thickness, earlywood is exposed in varying degrees.
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Early wood also varies from species to species. Compare Osage to say Maple.
Though many would prefer an intact single growth ring for a back, it's pretty clear that some are hoping for board type orientation to be better in every way.
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Pat, nice of you to mention those differences. I have had good luck with edge grain maple for backing
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Yes, it's very homogenous in structure. Maybe more so than any other typical backing wood. That may be why it surprises people despite not being considered as "strong" as hickory.
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i've made board bows from all 3. So they will all work equally well. I do prefer rift or bias. Jawge
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Jim D. -
Nota bene :
On May 21, 2014 at 3:00 a.m. I had an unexpected stroke : my left carotid artery was completely blocked and no surgically (or otherwise) intervention was possible. I was 64 years of age.
I had to learn how to feed myself & to walk & to talk & to write, etc..
The struggle continues to reprogram my neural context . . .
& reading and writing to this day.
regards,
Scyth
Kudos on the effort you have made and continue to make! Seems that even with your difficulties you are functioning better than a whole lot of folks
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Brad it started out at about 47# I think. The back was a single growth ring. I would have thought it would have taken more set. Back to not all wood created equal. And yes record breakers don't come out every time no matter how good a bowyer you are. Sure is nice when you get to wrk on wood like that. I just finished a bow from a 25 year old stave . No knots straight as a arrow . Great piece of Osage . Made the bow 68" long 2-3/8 at fades straight pyramid. The bow took about 2" of set. So well seasoned wood is not always best. Arvin
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The original post of this thread noted that the wood core of fiberglass bows was oriented so that its back and belly were edge grain because that was the strongest orientation.
But overlooked was the fact that the core of a bow limb has almost no tension or compression stress and mostly has to resist shear stress. So, that would indeed be the best orientation for uniform resistance.
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yes I agree that some woods may be stronger with certain orientation,,
but most the time I think a solid one ring back is best for self bow,,,,or will give best odds for success
I have been making bows a long time,, and the accumulated knowledge from other guys as well has shaped my opinion,, probably a mere hundreds of years or so of bow making experience all together,,keep in mind that in the last 20 years the sharing of bow making experience has raised the level of wood bow making dramaticly,, and I think one of the reasons we dont see alot of edge grain bows,, keep in mind,, not everyone post what they are making,,,I would say most do not,..and the orientaion of wood in a fiberglass bow,, really does not relate to wood bows that much,, I have made them,,I enjoy making all wood bows,,, I think you will see with the level of bow making now, that what is giving the best results consistantly,, is what most guys are doing,,
and it is not that much different from what the Native American guys were doing all along,, they had thousands of years to figure things out,,most of there bows were flat grain, or most of the bows we can see now,, for what ever reason,, but I dont think it was just tradition or accidental,,
or lack of being open minded,, thats just my thoughts,, from making and studying bows for the last 30 years,,
I have a friend that has devoted his career as archieologist to Native bows and arrows, and he tells me what we can see now,, is a very small percentage of what existied in the last thousands of years,, there is really alot we dont know,, and may never know..
I learn something almost every week here,one key point I think is important is that with edge grain as back, you have a mix of early wood and late wood,, that could weaken the back in some species of wood,, and that some have a better ration for a edge grain back,, I never really thought about it like that ,, and was a nice realization for me,, as always I like to learn something,,
I just knew that back in the day when I made alot of edge grain bows,, I always rawhide backed them them to compensate for the run out,, that that I felt might compromise the life of the bow,,
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You made a good point about edge grain and run out , any body that has done any amount of mill work making edge grain lumber or lams will tell you the difficulty in finding pipe strait wood to give you a full length edge grain stave with out run out , thats why you will see most glass bowyer scarf joint 36" lams together , there are plenty of glass bowyers using flat sawn lams as core material as well, including me , you here a lot of theories in the bow building world some times by people that dont make many bows
That at face value you think is good info but actually building the bow and finding out in real time can be different then whats being said really the only way to find out is build the bow thats really what its about any way !
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stick
I make edge grain stock from a board that is split. 2 halves of a 3/4" glued together work out good for 1-1/2" wide
just align the split edges together and rip the lams from as close to the split edge as possible. sometimes I can find a decent board in the stack at the store that is already split and get it for a discount
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Thanks willy I don't usually make lams over 36" other then for BB type lams so I don't have issues finding stock I was referring to longer staves & longer clean natural grain , you could also rip to narrow slats and re glue them and re mill them as action type wood for a stronger lam yet at a slightly heaver mass !
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Allright gentlemen, I got some first results. To shorten it a little bit, I skip the part about what I‘ve done and how I got to the result.
Here we go:
When splitting a log, no matter if large or small, it’s almost impossible to get a perfectly smooth splitting surface, to be used as a back right away. One can really see the disturbed fibers, where chips got torn out from the splitting and left groves. So I gotta scrape it and this is maybe already half the effort to chase the ring. So in that point there is no real advantage, compared to the common way.
The next point that could be an advantage is, that you can get a perfect rectangular crosssection from small logs. But logs that can benefit from this are rather small and hence hard to split straight through.
But for my feeling it is faster to rough out the bow that way. I have to admit here, that I‘m also trying to make a bow completely outside with minimal tools. Some kind of an anthropological experiment, I wanna feel how our ancestor bowyers used to do it.
By the way I used ash. Maybe maple works better for this. Elm is definitely not suitable.
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Why would elm not be suitable? In a quarter sawn situation, I would think the intertwined grain would help it hold together in the chance a splinter raised.
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Why would elm not be suitable? In a quarter sawn situation, I would think the intertwined grain would help it hold together in the chance a splinter raised.
He was referring to splitting, not sawing.
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Morgan,
Here's an example of quarter sawn Elm... Tough as nails... http://www.primitivearcher.com/smf/index.php/topic,52218.0.html
Don
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Yep, but note the detail he mentioned that eliminates Elm from a practical standpoint.
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Morgan mentioned a quarter sawn situation and I was just answering him...
Don
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OK, but hopefully he gets the other detail.
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OK, but hopefully he gets the other detail.
No sir. If it’s the detail of intertwined grain, I’m not sure I follow you. If it’s the comment of quarter sawn, I still don’t follow. You can split elm. It’s not fun but you can. In my opinion, if you split the piece then plane the exposed wood flat, to get a smooth surface, It does not differ much from a piece that is quartersawn at all. If you’re speaking of a detail that I didn’t say, please let me know what I missed.
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He was talking about achieving it with a more primitive scenario and getting a near clean back solely by splitting the wood. No saws, and likely no planes. Splitting most Elm without better than average splitting tools is a bit more complex too. This is not about whether it can be done at all or whether Elm makes a good board bow.
When you make a n Elm bow primitively you already have to make one interlocked grain surface smooth, doesn't make much sense doubling that.
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That´s exactly the point.
I forgot to say, when I split the log in halves I wasn´t happy with the surface, so I split it in quarters and the "quarter surface" was much better. I also have to admit that this ist the first time I use green wood right after cutting it down and rough the bow out with an axe. I was very surprised how fast and yet precise I got all the wood off.
Today I roughed out a second bow out of the other quarter I got from the tree (the other two are not usable). I stored it in water to keep the wood soft. This one I´m going to make the common way. The outermost ring is thick enough to be used as a back.
From that point roughing out the bow was easier to me with vertical grain. I also won´t make the heck off an effort to scrape the wood. I really wanna find out how much stress the splitting surface can take.
To summarize:
From what I can say now the only benefit is, the quick roughing out. But I´m still the opinion that a small log can benefit from being built reverse, as long as it can be split straight through. I tried splitting a small ash tree with wedges, but failed. Has anybody a tip on how to split small trees? Maybe hammering a large knife all the way through?
Regards from Austria/Europe (no kangaroos)
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But for my feeling it is faster to rough out the bow that way. I have to admit here, that I‘m also trying to make a bow completely outside with minimal tools. Some kind of an anthropological experiment, I wanna feel how our ancestor bowyers used to do it.
there were some examples of primitive bows made from splits in the new world. birch and osage as I recall and maybe also the quarter side as back.
my experience with splitting is that knots will make the grain runoff. to use wedges and avoid runoff, the split has to be through the center of mass, or center of strength so to speak. when the split off piece bends away from the wedge more than a the stiffer stock, grain will run off
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The problem with New World bows in a primitive sense is that they likely date from a time of metal tools or even lumber attained from milled lumber in some cases.
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my experience with splitting is that knots will make the grain runoff. to use wedges and avoid runoff, the split has to be through the center of mass, or center of strength so to speak. when the split off piece bends away from the wedge more than a the stiffer stock, grain will run off
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Thanks! Just to get you right:
The halfes must not bend away from the split. So the split line must be chosen so that:
The halfes become more thick than wide an hence bend less away aka are stiffer in direction 90° to the split line.
So hammering a knife through could help that too I guess
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The halfes become more thick than wide an hence bend less away aka are stiffer in direction 90° to the split line.
Not sure of the question above. Please try a different wording
generally, when wood workers split green wood the object is to control a split so that the work piece comes out close to the desired dimensions.
bending either side of the work piece creates runoff. a process called riving. It can be seen in the attached pdf
of course, a bowyers objective is to avoid runoff, so knots and excessive forces are to be avoided. a split not centered will create bending force,
a wider wedge creating more force, so yes, a knife could be a good tool for splitting evenly.
some woods follow the grain much better than others. where I am alder splits very well and birch is the worst. I am not familiar with ash, and believe ash in Europe may differ from ash in NA.
an interesting thought is....... just how much does a good split need to smoothed to work well in a primitive bow?
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Thank you very much for the file! That’s some really useful information! Probably I‘ll build me a riving tool.
What I wanted to say is, one should aim for halfes that are more thick then wide, so that they bend less away.
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Alright guys, I got some results:
But first things first. I recognized pretty early that the bow is going to be far too weak. I was a bit too eager at the roughing out stage aka was the roughing out too rough. So I had to remove quite a bit material to get it fairly smooth. But hey, that was the first time I roughed out a bow from green wood with just a hatched. But I didn`t do much sraping at the back. I really liked to see how much the splitting surface can take.
Because the bow would have become far too weak anyway I decided to just tiller it quick and dirty and left some weak spots, to really stress it out and see if the back or the belly fails first. Here is a pic at full draw. Please don´t mention the tillering tree. That´s not the usual way I do it.
(https://i.imgur.com/6TBsqhm.jpg)
One can really see the weak spot in the right limb (that´s the upper limb) near the handle. The midsection is too stiff. The left limb is the lower one and bends ok, but it´s much stiffer than the other one.
As you might expect, the weak spot got overpowered and started crysaling. The bow drew 15# at 28".
So I shortened it from 70" to 66" inches and drew it again. It broke at about 20".
I inspected the broken section to find out, that the belly collapsed. Heres a picture of the broken area.
(https://i.imgur.com/U8f52DP.jpg)
(https://i.imgur.com/6fgnnne.jpg)
Then I also bent the intact limb by hand to see how much it can take. I bent it till I could here a cracking sound and checked the wood. The belly started to collapse, while the back was still fine! Then I caused it to break.
(https://i.imgur.com/5A4UfPM.jpg)
(https://i.imgur.com/BrjDzMa.jpg)
(https://i.imgur.com/R4VOYkZ.jpg)
The fact, that the belly got chrysals before the back failed tells me, that the split surface works as a back just fine even with some imperfections and doesn´t need a lot of scraping and smoothing.
Here are pictures of the back before tillering:
(https://i.imgur.com/lFSlNvh.jpg)
(https://i.imgur.com/6pO4KzC.jpg)
To me using vertical grain is not necessarily faster then using the outermost ring under the bark. For sure it´s less effort than chasing a ring. And I found the roughing out quicker. I still wanna try to make a bow out of a small log that is just split in half and use the splitting surface as the back. A reversed bow if you want. In that case the advantage would be the rectangular cross section instead of the high crown a small log usually gives. But I postpone this to spring when the wood is more pliable an easier to split.
greetings from Austria
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Nice that you followed through with the experiment.
I'm not following you with the advantage of a rectangular cross section, besides maybe being easier to work.
Wouldn't tension strong woods such as ash like you used benefit from a crowned back and flat belly? It seems that increasing the surface area of the back and decreasing it on the belly would only increase the difference between the already mismatched tension/compression strengths.
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...Wouldn't tension strong woods such as ash like you used benefit from a crowned back and flat belly? ...
Just for the record, almost all woods are 3 to 4 times stronger in tension than compression.
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Good point indeed! I‘m just relating to what is written on rectangular shape in the TBB.
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good to see someone that like to experiment. finding out whether a certain kind of wood is "tension strong" or "compression strong" is not that easy. any imperfection in the back can cause a catastrophic failure, while a belly can chrysal in a number of places before a bow limb folds.
the descriptions are somewhat of an invention of Tim Baker.
any moisture more than Ideal will usually cause premature compression failure, and give the appearance of the wood being "tension strong"
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That’s a good point. But I‘m gonna redo the experiment in spring, to verify the results.
I‘m about to finish the bow from the second stave of the same tree. I did this one the common way.
It’s 71“ long but quiet narrow, only 35mm at the fades. It also turned out at the weak side and draws 25#. I still have to get used to using green wood and roughing out with a hatched.
I had planed to temper the belly anyway, but at that occasion I could flip the tips a little bit and/or string it reverse while roasting. I‘d like to reach about 35#.
Let me know when you think!
https://i.imgur.com/d4UenB7.jpg
https://i.imgur.com/bmBvgWj.jpg
https://i.imgur.com/1BnzkAc.jpg
Thanks!
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The fact, that the belly got chrysals before the back failed tells me, that the split surface works as a back just fine even with some imperfections and doesn´t need a lot of scraping and smoothing.... .
What this shows is what has been known since the first engineering tests were done: wood is stronger in tension than compression.
It says NOTHING about the relative strength of vertical grain wood compared to "horizontal" grain.
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bump it up to about 50 ish,, and it will tell you a bit more about the wood,, )P(
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The scope of the experiment was, to see if the splitting surface holds up as a back. Even mostly unscraped and with imperfections.
My thinking is, the back would have failed before the belly, when overstressed, if the imperfections would have done too much harm. And that is supported by what you say: the wood is always more tension strong, but the sides would have changed, if using the raw splitting surface, changes the tensile strenght properties.
But exactly that isn‘t the case, the belly failed and which shows, that the back is still stronger than the belly.
In short: I wasn’t about to show if vertical grain is stronger. I guess you haven’t read all of my posts.
@brad:
Do you mean the one I showed in my last post or when I redo the experiment?
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In short: I wasn’t about to show if vertical grain is stronger. I guess you haven’t read all of my posts.
Silly me, I was fooled by the title and all the earlier posts that talked about that subject.
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when you experiment,, I think the heavier bow will give you a better represetaion of what the wood can or can not do,,
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That’s the plan for the next try :BB
What do you think about the bow I showed recently?
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you might try shortening this one actually. the tips are not really working anyway, you might want to make the right limb bend as much as the left
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Thanks Willie!
But I actually decided to discard this one and take it as a practice piece in primitive bow making. I harvested another ash recently. And now I think I got the hang of it on how to make a bow with more primitive tools. I learned the approach is slightly different than doing it on a workbench with a draw knife, but it works just fine. I just need to get acommodated to it.