Primitive Archer
Main Discussion Area => Bows => Topic started by: Aksel on March 26, 2024, 06:14:40 pm
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I always like to think about, and make historical replicas of old bows and I recently posted a flat bellied lever-tipped elm bow. The bow shoots really great and everyone seems to agree on flat bellies are the best for "white woods" to keep set low and speed up.
But when I look in my books on stone age bows -the golden age of self bows - I always wonder about all the bows with rounded bellies, because they existed parallell with others with flat bellies, some even found together.
The famous Möllegabet bow has rounded belly
Several of the Tybrind Vig bows (about 2 dozen lever tipped bows) have rounded bellies
The 2 most extreme AND refined lever tipped bows, the Hjärnö bow and the Maglemose Vange- bow (last one a 74" lever tipped bow) have lentil shaped bellies.
Also, several ordinary flatbows have rounded bellies.
If those superb bowmakers made the effort to shape rock-hard elm with stone tools into Lever tipped bows (and presumably understood the mechanics behind them), wouldn´t they also have understood the "benefits" of flat bellies -especially since they made others with flat bellies? I´m thinking there must be something over looked here... These bows existed over thousands of years over large areas.
I have made successful bows in the past with lentil shaped bellies, also with low set, but abandoned them due to "common wisdom" nowadays.
I´m curious on everybody´s thoughts on this!
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I've wondered about this too. Chuck Loeffer, following Native American design, uses a lenticular cross-section in his juniper-sinew bows too, and I've never quite understood why.
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I think at least part of the reason for a not totally flat belly, is due to primitive tools. It's easier to do a flatish lenticular cross section than a totally flat belly, even when using modern hand tools. Even a steel card scraper has trouble along a wide limb, removing wood evenly across the width, with one pass. Yes, it is achievable with rasps and scrapers but harder in my opinion.
Dean Torges book, Hunting the Osage Bow gives good reasoning for the faceted tillering approach, which delivers a lenticular cross section. How the bow bends along the limb is mainly controlled on the peak of the belly, and weight reduction and limb twist mainly on the outer edges of the belly.
Torges also thought the modern flatbow, came about with the availability of the stationary belt sander and drum sanders, in mass production. These tools automatically try and create a flat belly when used to tiller.
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flat bellies stress the back more.
reliability trumps performance and a soft shooter works better than a broken back.
consider a whitewood bow that may get back dings and dried out over a fire sometimes.
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I think at least part of the reason for a not totally flat belly, is due to primitive tools. It's easier to do a flatish lenticular cross section than a totally flat belly, even when using modern hand tools. Even a steel card scraper has trouble along a wide limb, removing wood evenly across the width, with one pass. Yes, it is achievable with rasps and scrapers but harder in my opinion.
Dean Torges book, Hunting the Osage Bow gives good reasoning for the faceted tillering approach, which delivers a lenticular cross section. How the bow bends along the limb is mainly controlled on the peak of the belly, and weight reduction and limb twist mainly on the outer edges of the belly.
Torges also thought the modern flatbow, came about with the availability of the stationary belt sander and drum sanders, in mass production. These tools automatically try and create a flat belly when used to tiller.
Facet tillering method makes some sense but doesn´t explain why they did some bellies flat and others not. One Holmegaard bow is +2" and has a perfectly flat belly. Other bows´ bellies are very deliberately shaped high with a well rounded belly. They also change the cross section of the lever part on several bows which makes me think there is logic behind it. You can see in the 2nd illustration how they even shaped the back of the bow to get that particullar cross section.
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flat bellies stress the back more.
reliability trumps performance and a soft shooter works better than a broken back.
consider a whitewood bow that may get back dings and dried out over a fire sometimes.
Almost all these bows are made from elm which can handle stressed backs well, and some of them did have perfectly flat bellies. They obviously thought about peak performance with some of those extreme lever tipped bows - but made them with lenticular shaped bellies. Between this bow illustrated (Hjärnö) with rounded belly, and the older holmegaard bow with perfectly flat belly, there is apr. 5000 years! Makes you wonder...
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I've wondered about this too. Chuck Loeffer, following Native American design, uses a lenticular cross-section in his juniper-sinew bows too, and I've never quite understood why.
I don´t know much about native american bows, even less of sinew backed bows. But I have worked with juniper, it´s nice and sof and easy to work. Maybe did they go for lenticular cross section because juniper is less tension strong?
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Ever notice how we all build different styles of bows? I can see a certain bow and tell you which member made it (some of the time). Maybe it’s the same throughout history with different builders having different design preferences. And then there are the bows built in a certain style because that was what the wood gave us. I imagine two bowyers sitting around a fire thousands of years ago having this same debate.
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Haha yes that has of course some truth to it, but I don´t think, over thousands of years, the tried and tested designs they came up with has as much to do with taste as with functionality since they depended on those weapons. In Switzerland they made yew bows with concave bellies instead, which also must have had to do with performance and not taste.
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a question about the Hjarno a little off topic if you dont mind.
do you have or can point to any pics of a hjarno style that show handle details or crossections?
thanks
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willie: its handle is 29 mm thick and 24 mm wide. Looks comfortably rounded. Reported to be 120mm long. I do not have other details of the grip but there are pics: https://www.tradgang.com/tgsmf/index.php?topic=178571.0
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Interesting post. Now that I look back at my builds I can say that I tend to make my yew bows more rounded/ lenticular belly then I do with hardened white woods or Osage bows. Not to say that I did this deliberately but more subconsciously I think. Maybe more of a styling thing or by feel. Not sure on this actually. It just seemed like they looked and felt better made that way. I cannot say that I’ve done enough testing of each shape to see a particular performance advantage either. I think that kidder is onto something about personal preference factor and personal style of bow builds. This being said we bow builders today still like to replicate things that we admire. A personal reflection for me is the mollegabet style bows. I’ve made several of them and have never claimed that they are replicas or dimensional copied even. I make them loosely based I guess while adding my own flare to them. Some may say this is subjective and varies wildly even in deliberate replicas. I wonder if this is partly what has happened over time with bows that seem similar in style over time in this case thousands of years.
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Superdave, for sure can trends play a part in this, but i wouldn´t think they would last over 5 thousand years if performance didn´t play a big part in it also.
With the wooden bow revival -over the last 30 years or so - we keep "discovering" things stone age man knew 10´000 years ago; super skinny tips, sapling bows, lever tipped bows, Hollow limb design, probably fire hardening as well just on top of my head. I am convinced there are more things to discover, and cross sections are one of them. ;)
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Hey Aksel, I don't doubt there are paleolithic bows out there with really flat bellies, It would just be harder to make them flat, vs lenticular, especially with stone, or bone tools
The cross sections that you show are lenticular in the working portion of the limb(wide), one is flat on the narrow non working or barely working portion.
That makes sense to me as very little tillering needs to be done on the levers, once you have initially roughed in the intended dimensions . The width is very narrow here, so it matters less if its flat or rounded, as its not as difficult to get the intended result. The wide working portion is a different matter.
The lenticular cross section lessens the chance of twist, as the centre of the belly acts as a keel. Over a 2" wide working limb, it still acts as virtually flat, without the difficulty of achieving a perfectly flat belly. Even though the bellies on these bows are not truly flat, I've always seen them referred to as flatbows.
The concept of flatness, or straightness, especially in pre modern times was relative. Design was organic, with no dimensions other than hands, finger widths, spans etc. If it achieved the desired result, with less work, then that's likely to be more common.
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I always like to think about,
and in the Americas, rectangular cross sections developed in similar cultures, but maybe after contact with metal tools?
the sudbury, of course might represent a more "traditional" NA design
it would be interesting to see if there are any surviving examples of pre-migration Asian bows
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I think this is likely difficult to determine and more than likely a matter of doing what works with what we’ve got. I don’t think a flat versus rounded belly makes enough of a practical difference for bowyers to notice and choose one over the other from both a performance and safety factor. I can’t say with certainty but it seems our knowledge of engineering and physics helped us understand that relationship more than discovery from trial and error in bows. As with evolution, if it works good enough it survives. Doesn’t have to mean that it is necessarily the best.
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We should also remember that we are talking about a relatively small sample size - we probably have a few hundred (?) surviving examples (many of which are only partial examples) over a period of thousands of years where we have to assume that probably millions of examples were made by many thousands of bowyers. To take a single or even a few similar examples from a specific time period and location and extrapolate that to conclude that “bows of this period, or that location were ————“ is probably beyond what can actually be said. I think the only safe conclusion is where environmental limitations necessitated a particular design ie cable backed bows by the Inuit.
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Just a couple of thoughts...
'Flat' doesn't occur very often in nature ( although, some rocks cleave flat and Ice is pretty flat) , and you tend to need something flat to create another flat surface. I suggest the curve is simply a more natural shape resulting from the working practices.
from a technical stand point, I think a flat belly tends to become slightly concave as it is bent and concentrates stress on the edges?
Del
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Hey Aksel, I don't doubt there are paleolithic bows out there with really flat bellies, It would just be harder to make them flat, vs lenticular, especially with stone, or bone tools
The cross sections that you show are lenticular in the working portion of the limb(wide), one is flat on the narrow non working or barely working portion.
That makes sense to me as very little tillering needs to be done on the levers, once you have initially roughed in the intended dimensions . The width is very narrow here, so it matters less if its flat or rounded, as its not as difficult to get the intended result. The wide working portion is a different matter.
The lenticular cross section lessens the chance of twist, as the centre of the belly acts as a keel. Over a 2" wide working limb, it still acts as virtually flat, without the difficulty of achieving a perfectly flat belly. Even though the bellies on these bows are not truly flat, I've always seen them referred to as flatbows.
The concept of flatness, or straightness, especially in pre modern times was relative. Design was organic, with no dimensions other than hands, finger widths, spans etc. If it achieved the desired result, with less work, then that's likely to be more common.
I agree that it might be harder to make a flat surface than a rounded with stone/bone tools. But I have made one elm bow with stone/bone tools and I managed to make the belly flat without much effort (especially since I am not a flintknapper, only with broken up flint stone). I also think modern people tend to under estimate the skill of the people of olden days. Also is the way we value/measure time completely different to theirs. But sure it make sense what you´re saying, although I don´t think (in general) they would take the "lazy" time saving route before the better more time consuming one and compromise with performance. But that´s only my feeling. Nice though to think about it and hear everybodys thoughts on this.
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I always like to think about,
and in the Americas, rectangular cross sections developed in similar cultures, but maybe after contact with metal tools?
the sudbury, of course might represent a more "traditional" NA design
it would be interesting to see if there are any surviving examples of pre-migration Asian bows
Yes, I´d be interesting to find this out
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I think this is likely difficult to determine and more than likely a matter of doing what works with what we’ve got. I don’t think a flat versus rounded belly makes enough of a practical difference for bowyers to notice and choose one over the other from both a performance and safety factor. I can’t say with certainty but it seems our knowledge of engineering and physics helped us understand that relationship more than discovery from trial and error in bows. As with evolution, if it works good enough it survives. Doesn’t have to mean that it is necessarily the best.
True, could be so. But then I wonder why they did the lever bows since it is a more extreme and complicated design which takes more work and most likely was to make bows that would cast the arrow faster - they could have stayed with simple flat bows. And it might also be so that the rounded belly was advantageous in some way we´re not thinking of yet. I remember Tim Baker said in TBB4 when they measured arrow speed from different bow types that the bows with rounded belly performed unexpectedly good, despite more string follow -probably due to lower limb mass.
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We should also remember that we are talking about a relatively small sample size - we probably have a few hundred (?) surviving examples (many of which are only partial examples) over a period of thousands of years where we have to assume that probably millions of examples were made by many thousands of bowyers. To take a single or even a few similar examples from a specific time period and location and extrapolate that to conclude that “bows of this period, or that location were ————“ is probably beyond what can actually be said. I think the only safe conclusion is where environmental limitations necessitated a particular design ie cable backed bows by the Inuit.
Maybe 100 bows from early+late stone age in Europe. Tim Baker said in TBB about the Holmegård bow" it was preserved by a random act of nature and is therefore probably a random bow of it´s time". Not sure if that´s true but we have the material we have and there are patterns. But sure, we can never be sure. My main thinking on this question is that there can´t be anything random or only "fashionable" in something that has lasted for thousands of years. Must be something that works very well.
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Just a couple of thoughts...
'Flat' doesn't occur very often in nature ( although, some rocks cleave flat and Ice is pretty flat) , and you tend to need something flat to create another flat surface. I suggest the curve is simply a more natural shape resulting from the working practices.
from a technical stand point, I think a flat belly tends to become slightly concave as it is bent and concentrates stress on the edges?
Del
Some things are flat in nature. The surface of a lake, the horizon and I have seen a tool box made from oak boards from Neolithic times. So surely they knew how to work wood and knew the concept of flat. But I see what you mean - you have a point, but evidently there are bows with perfectly flat surfaces. That a convex surface flattens or becomes concave when bent is true and an interesting thought, I will have to think more about it.
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I have been looking a little closer on the finds and it seems there is, perhaps, a clue:
The bows with flat (or close to flat) belly all seem to come from a sapling of around 2 inches.
The bows with a lenticular cross section all come from larger trees, around 4 inches.
My first reaction was thinking: it´s probably to much work to work a thicker sapling flat, but they seem to have been looking for a symmetrical cross section. The bows with a more rounded belly are also worked on the back to get that symmetrical lenticular cross section, others have a rounded belly to match the crown of the back. You can see this in the images I posted in the previous page.
Does this seem logical and anyone got a clue why?
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what seems illogical when looking at the top pic you posted in reply 4, is why, when working with an apparently larger diameter stave, the bowyer would create extra crown on the back by rounding the back edges so hard?
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willie, yes it´s a bit mysterious. Especially on such a bow where the maker was trying to push the stave to max performance with really long stiff-ish levers. But it´s deliberate and seems he wanted that symmetrical thick lenticular cross-section. That bow is estimated to 74 inches btw...
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TBB 3
North Andaman Island bow staves were selected from small-diameter trees having a natural reflex in what would be the mid upper limb only. The stave was decrowned, back and belly, creating a wide, flat lenticular — therefore very flexible—finished limb. South Andaman Island limbs were straighter. Longman reported a similar design in the New Hebrides.
although maybe lenticular in this description referred to width profile rather than crossection profile
pics showing crossection with flat belly
https://www.tapatalk.com/groups/paleoplanet69529/some-details-of-a-south-andaman-bow-t38355.html
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Willie, yes I´ve seen those on PP.
Fascinating bows and proves that "primitive" people went to great lengths making very sophisticated bows with simple tools and didn´t settle for something only good enough.
Those incisions in the pictures btw resemble some found on mesolithic bows. Interesting.
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I think this is likely difficult to determine and more than likely a matter of doing what works with what we’ve got. I don’t think a flat versus rounded belly makes enough of a practical difference for bowyers to notice and choose one over the other from both a performance and safety factor. I can’t say with certainty but it seems our knowledge of engineering and physics helped us understand that relationship more than discovery from trial and error in bows. As with evolution, if it works good enough it survives. Doesn’t have to mean that it is necessarily the best.
Very true! I’ve played with this for twenty years now with Osage. Flat belly’s , long and skinny, rounded belly’s , wide flat belly’s, trapping the backs, narrow tips , reflex,deflex, and a SHELF ,all the time trying to achieve a faster smoother bow. And I keep going back to the bow you see me post so often. Bowyers of a thousand years ago were no different I’m sure.
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And I keep going back to the bow you see me post so often. Bowyers of a thousand years ago were no different I’m sure.
And I would like to think that any number of good designs would suffice, and at some point, a more deciding factor is the skill of the bowyer to execute exceptional tiller
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And I keep going back to the bow you see me post so often. Bowyers of a thousand years ago were no different I’m sure.
And I would like to think that any number of good designs would suffice, and at some point, a more deciding factor is the skill of the bowyer to execute exceptional tiller
I agree the best with there tools and can read a stave will be looked up to. Lots of those guys around this forum.