Primitive Archer
Main Discussion Area => Bows => Topic started by: Sasquatch on November 21, 2014, 02:18:03 pm
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In the books there are many bows with completely rectangular cross sections. Almost as if they decrowned the staves. Well did they? I don't think the books inform you if they did or not.
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If you don't mind, Sasquatch, I will add the question: doesn't de crowning automatically violate rings?
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What type of wood? Some it doesn't matter? Juniper? >:D
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Juniper would deffinatly matter :o. But I think that they were hickory, elm, I really cant recal.
My question is how do these bows show a perfectly rectangular cross section without decrowning? did they have backings?
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Just because a stave has been de-crowned does not mean it has violated rings
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In a short answer, yes they are rectangular in cross section. No they are not decrowned. Not for the large part anyway. I'm not trying to be a wise a$$ but how do you not understand the cross section? Rich (halfeye) and myself discussed this topic in a post a while back. I'll try to find it. Don't over think it. It really is as simple as it sounds.
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In a short answer, yes they are rectangular in cross section. No they are not decrowned. Not for the large part anyway. I'm not trying to be a wise a$$ but how do you not understand the cross section? Rich (halfeye) and myself discussed this topic in a post a while back. I'll try to find it. Don't over think it. It really is as simple as it sounds.
I understand what a cross section is... but on a typical tree the outside is rounded. Therefore if the outside of the tree became the back then it should have a curve to it also. But many of the bows don't show that curve.
Mark.. I agree, but typically rings are not thick enough to make it a flat back, unless the tree is very large in diameter. Native Americans were not cutting down big trees like that as a norm.
With modern tools and time it would be easy to find a ring that we could make flat. But even if we did find one i wouldn't want to keep scraping away hoping that the next scrape didn't tear through the lower ring.
Just so everybody knows Im not trying to start some crapy thread/argument. I just wanted to know why there are so many of the bows listed with completely flat backs
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There's no reason to believe native Americans/ First Nations weren't capable of falling large trees.
Sure, limb and sapling bows were probably way more common for the average joe for many reasons,
but nice bow staves were of high trade value then, just as it is with us.
I highly believe there were people who spent lots of time cutting and splitting staves for trade.
The First Nations in my area carved 10+man canoes out of one old growth cedar tree.
Would apparently take a team of guys over a week to fall one, but that's nothing compared to a 12" diam Osage tree.
Also, just because a tree is round doesn't mean all your staves will be crowned. I cut a 10" diam black locust, and a couple staves have backs flat as boards.
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I understand that they could have felled big trees. Thats why i said "the norm". I appreciate all the answers, but I don't think that anybody has answered the question. I know what is possible with many woods.
My question is were the bows in the book all flat ringed, decrowned without violating the rings, or were the rings violated? Thanks again for answers. :)
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I don't know it these bows were made with decrowned staves or not. I don't remember seeing end grain which would tell for sure. If decrowning is done properly the grain "violations" would be longitudinal and not across the grain. When you go across the grain splinters can lift. When you decrown properly the cuts run with the grain so splinters are less likely to lift.
I have seen quite a few Native American selfbows with grain violations.
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Thanks pat! I appreciate the answer. I guess I need to do more research on grain, and how to decrown a stave etc. Any good resources about decrowning other than TBB series?
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You can have a small diameter tree with tight rings and still have no violations. A ring violation is when the ring is cut through to the next one across the back. You can decrown and as long as each ring runs the full length of the stave then you are good to go
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The drawings you are referring to are just that, Drawings. They are not meant to be "blueprints" so to speak. The drawing of the cross section does not mean the back or the belly is perfectly flat. It is just showing the general design of the cross section. I have an opinion that the design of the bows you are referring to is a "universal" design for a typical type of bow and cross section that will accommodate many wood types. You can make up for a lack of width with thickness. Keep in mind this is purely my opinion from making many of this type of bow.
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Not to beat this to death--I respect everyone's assessment as to there being no ring violation (even though I do not completely understand it)--I think the basis of my own misunderstanding is this:
If you have a stave with curved back, and view it from the end, the rings are of course curved as well. So if I imagine flattening that curved surface, I am unable to picture how you do not cut through (at the very least) that outer good ring. I plan to do more reading about this.
Best regards,
Russ
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Most likely because you don't quite understand what constitutes a ring violation.
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Here's a simplified illustrated description of what you are asking. Makes more sense when you see a picture of it.
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What causes problems is when the wood fibers are compromised/cut; keeping the back as one complete ring is the easiest way to keep undamaged fibers, but not the only way. The board bows chapter of TBB II is probably the best visual explanation of this. Decrowning makes the back of the bow look like an edge grain or quarter sawn board with straight grain; the grain and fiber lines run parallel to the edge of the board/stave.
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...like randman said just before me with a very useful illustration!
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Sasquatch,
If you are wondering about a, "completely flat back" then yes you are right there's rarely a truly flat back along the entire length of the stave or bow. Its just a concept that you keep in mind when designing or building a bow.
However, there are "flat" backed bows because if you look at any tree cross section you will often see that, even though the tree appears round, it really isn't, because as you look at the rings you will see flat sections of the circle that the ring creates.
So a 1 or 2" wide bow can have the appearance of a flat back even though, had you chased the ring perfectly, you can lay a straight edge across it and see that is does indeed curve or round at the edges.
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I doubt the artist took actual profile measurements with one of those thingamajigs that measure that.
I wouldn't be surprised if the bows depicted from woods suitable for decrowning are not actually decrowned though.
It is not too hard to find a tree with at least one flat side. Often trees growing in a situation conducive to that actually will have a slightly concave back.
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Marc,
I think you were exactly correct about my misunderstanding of the concept--that is, until
I saw randman's excellent illustration. Don't want to continue to jack this thread, (and I may still be off base) but it seems to me that it is OK to cut through the back rimgs--so long as thou carry that grain line all or most of the way to the ends of the stave.
Thanks!
Russ
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I've looked at those illustrations many hundreds of times since I got those books several years ago and all I can say is that each bow must be evaluated separately. Many bows have rectangular cross sections, yes, but they are not all made the same way. Some are decrowned, some are biased ringed, some are made from large diameter logs, and some have violated rings. Some are very short draw bows and some have very long draws. Many are made from Hickory which is very forgiving of grain violations. And some of the illustrations are just plain inaccurate because of a lack of data, for example.
The thing to remember is that a rectangular cross section is very safe and many bows will be made this way by default. From what I have seen of the real things, the bows are made from the best piece of wood available. This usually means the backs are very clean and free from lumps, high crowns, and/or undulations.
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Yeah they didn't mess around back in the day with the snakey, roller coaster, character stuff we all got time to mess with....feeding your family was serious business and bowmakin wasn't just a hobby....Jackcrafty, the list of bow styles you mentioned sounds a lot like this forum. :laugh:
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TimBo, gave an excellent description.
The purpose of decrowning is to counteract heavily crowned staves which concentrate too much tension right down the middle.
Decrowning requires some finesse and time. The payback is not all that great and it is easy to make a mistake and violate that longitudinal grain.
In the past I just left heavily crowned staves a few inches longer.
I saw some decrowned or board bows at the Harvard's Peabody Museum. To me they looked to be bows made from boards.
Jawge
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The illustrations that Rand posted are good and a properly decrowned stave would be #2