Primitive Archer
Main Discussion Area => Bows => Topic started by: Prarie Bowyer on December 02, 2014, 07:31:15 pm
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Doing research and finding it hard to find the details. Found this handy and thought I'd post for others.
http://ecoecoman.com/kyudo/item/yumi_seisaku_01.html
Then there is the YouTube videos of Jaap k.
And the guy who smokes his bellies for months.
https://m.youtube.com/watch?v=yX6DFD1_aZk
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Wonder which is more effective the long smoke or the belly burned core?
Also are the rinds tapered or is the core tapered?
Is there a taper in width towards the tip?
Is the nock like a belly underlay or does it butt up to the belly boo?
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there is also a good build along over on paleoplanet, let me see if i can get a link to work. ???
http://paleoplanet69529.yuku.com/topic/55920/Rope-and-wedge-bowmaking-buildalong#.VH5WeNJDuSp
oh hey it did cool ;D
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there is also a good build along over on paleoplanet, let me see if i can get a link to work. ???
http://paleoplanet69529.yuku.com/topic/55920/Rope-and-wedge-bowmaking-buildalong#.VH5WeNJDuSp
oh hey it did cool ;D
Awesome! Exactly the sort of thing I was looking for!
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http://paleoplanet69529.yuku.com/reply/502492/A-bevy-of-bamboo-composites#reply-502492
More of his work. Hmmmmmm. Till now I'm strictly a PA guy. Wonder if he is on here?
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Hi Prairie Bowyer: I'm the guy who did the works on Paleoplanet. Making a yumi is quite difficult, but please go ahead and try to build one as you'll learn a lot from the experience I'm sure. Something very important to keep in mind is the spacing of the nodes on the back and belly bamboo plate. I measure them when I cut them in the grove and set these apart, as they are specific to this bow. Next I would make the laminated core as it is way better for performance than just a plain wooden core. The core is then thickness tapered and this determines the draw wt. of the bow. After you glue the bow you can do some tapering of the tips , but that's about it. Setting the curves during glue-up is critical ,in where they are located and how much to impart. Do some dry runs before, to get practiced. I make the hybrid now, as it is much more stable and user friendly. If I can be of more help please ask. You can see more photos of these bows at bowsforpros.com
I hope this helps a bit in your project. Steve Thomson.
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Sorry. I forgot to tell you that there is one more submission on paloeplanet in the composite bow forum, called "yumi-esque hybrid" which you will find interesting and could be of help to you. Could be 5 or 6 pages back. Please let us know how things work out. Take care.
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Wow cool!
I was going to buy another bag of 25 bamboo slats. I kinda don't like the look of the true yumis but I love the hybrids. But it looks like yumis are strong performers?
What about the thickness in the middle in the grip area? Bamboo is all knife edged thickness from end to end?
Could a person get the same effect with bike tire tubes as the wedges? I've done it on a smaller scale for splicing and repairing arrows.
I was planning to try the following for my first one.
Try to find two rinds that are close to each other in terms of node spacing. I'm guessing in the bag of 25 there will be several from the same stalk.
Cut both to 68".
Use verticle grain carbonized boo flooring for the core. Make it 3/4-5/8" wide with a "z"splice in the middle. Possibly burn it a tad. Then taper it to a slightly narrower tip.
Then glue on hard wood squares along the edges of the bamboo core so they follow the narrowing at the tips.
When that is dry plane it flat then thickness grind in my taper of 1/4" from center to tip leaving a level section at the grip. Taper both sides?
The core will be pretty much finished at this point.
Lay that on my bamboo rinds with registration marks to align the parts and trace around it.
Saw out both rinds then saw, plane and belt sand to thickness using a small block plane to clean up the edges from wavers and saw marks.
Cook the belly with a heat gun.
Scrape grooves in all with a large tooth hacksaw blade. I like daap weld wood plastic resin for boo laminations. Wrap the glued pieces in Cling wrap and slide them around as needed for alignment.
Wrap in skinny bike tubes with a small gap between wrappings so I can monitor. Try to get my bends in for the recurves and possibly some reflex at the center. Just a little for the first one.
Into the hot box.
After unwrapping clean up with a small Block plane and file. Tiller it by planeing the edges.
I'm intrigued by the knocks on the belly so I may try that. Saw the rind off the belly at the tips and clean up with plane and sanding block.
Make a mullberry knock that is also a Grumley knock? Possibly just the regular. Match the contours and glue with TB3.
Cut the pin nocks, sand and finish the bow.
Dye it black and then use a few coats of either lacquer or shellac and wax.
Wrap the cane arrow pass, leather grip etc.
go shooting.
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http://paleoplanet69529.yuku.com/reply/476897/A-new-yumiesque-hybrid#.VIDvm4hOKrU
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There are a lot of things that I have no experience with, regarding the materials and method you suggest of putting the pieces together. I was trained a certain way ,and that is what I try to stay true to. I'm not saying that what you propose will not work. The hybrid I make is 72 inches long, and that would be able to take a 33 " draw.Making yours at 68" would be too short to get the curves in proportion needed to get that shape. I do bow making classes , and could show you how to build the bow and I have bamboo for sale which would be appropriate for these bows. Perhaps consider that as an option to get you started. See the contact page on the website I referred to , and contact me privately. Getting a bow and learning how to do it for a reasonable cost is a good deal if interested.
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These are tricky things to make. Good luck and i'd take Steve up on his offer. :)
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Well .. I'm going to try it first. Ok to the length. Though I did do a much Shorter Boo back and belly recurve previously.
I'm not seeing why logically the rubber tubes would not = the wedges method. Unless there is something beyond friction locking the bow in that shap while glue dries.
Question: Some of the Originals are made using Deer hid based hide glue. Have you ever tried to make these with TB3?
Note on length taken. I love the look of them. How are you finishing them. Laquer?
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I've watched a few of those yumi making videos and the way they pound in those wedges I bet you would need over 300 psi to equal it with a hose(OK that's a WAG). But still, I'm amazed that there is any glue left in the joint. Plus they can localize the pressure if they want. Remember one wedge can tear apart a hickory log and they must use 50 or more.
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Prairie Bowyer: In Japan, the really high end yumis still are made with hide glue. The issue with hide glue is that it will gel and set, before you can get everything done with putting the bow together and setting the curves. So they use a steam hood , which keeps the glue fluid and moist until the bow is complete. Hide glue is also prone to high humidity, which is why they laquer the bows to seal them. I like to use G2 epoxy from Lee Valley ,which gives me more than an hour of open time. Usually it takes me 1 hour to glue and wrap and set curves before putting into the hot box. You could try the rubber band method , but I don't believe the wedges will be held tight enough to set the curves. I have not used it myself. With the rope, I set the tension when wrapping and then tighten the wedges to create a nice even pressure along the bow , and this will allow me to set the curves and hold the shape I want. Always check to make sure the bow is not twisted some way, as you cannot correct it much after the glue sets.
As for finishes, I use leather dyes to stain the bow and then several coats of polyurethane to protect the limbs. I've been doing this for 12 yrs. now and am still learning and trying different things, but the rope and wedges is still what I use for all my bows because it works well for me. So try some thing different and see how it works for you. That's what bowmaking is all about. Let us know how things go.
Steve T.
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Will do.
what little I've done with the rubber band method is with out wedges. Wrap them tight and no need for wedges.
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I'm not real clear about how the Yumi "knock" block are arranged. do that go over the bamboo or is the belly bamboo shorter and they butt up against it?
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question:
How do you smooth the transition on the cores that you added wood thickness to like the Indian bows?
What is the material above and below the grip and arrow pass?
How thick is the core at the center on the wasabi bows? Love that bow with black and yellow!
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Prairie Bowyer: Well, I think the knock block you refer to is what I call a static plate, which is glued to the belly side of core when the bow is glued together. It is butted against the belly bamboo plate .
The material used for the arrow pass is rattan. Chair caning material. It comes in various widths, so I use thicker for the arrow pass and thinner for below the grip and bow tips. Sometimes craft stores sell it. I told you how to apply it in a previous message.
As for the thickness of the core at the center of the bow, it varies depending on the draw wt. needed and the wood used in the core. I usually make it say 5/16 " to 3/8" but you'll have to play around with that for yourself.
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I'm going to do a few dry runs with the moso I have access to. Then we'll talk about some madake?
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Further research has suggested that the number of laminations in the core can vary and be as many as 5? I notice that you are using 3.
Would there be a performance difference if the whole core were laminations if boo core?
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Sometimes I make a fully laminated bamboo core, and I find that when you add the dense hardwood along the sides , the result is a bow which takes less set and is better in performance. Especially in longer bows like you are wanting to make. I believe that Japanese bowmakers of old, discovered the same thing, otherwise they would have used an all laminated bamboo core. There are so many combinations of core materials and the way they are oriented, that your imagination is the only limit. Using 5 bamboo and 2 wood in the core will give a nice smooth draw, and using 3 lams of bamboo and wood along the sides will yield a stiffer draw. When I make a bow for someone I consider the person using the bow and how they want it to perform. Ex. hunting or target shooting or long distance shooting etc. Shooting heavy arrows or light wt. arrows. Long draw or shorter draw, on so on. Then I choose the bamboo for the core and the wood matched with it . It's the core which is the engine for these bows, and that's where the speed and cast come from. Of course there are other factors influencing a bows performance.So how are you getting along so far?
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Tend to do WAY too much research and thinking before starting a project. I've hot 2 yew bows on the bench and need to order my next bag of boo.
I have some mulberry I. Thinking of using on the sides for the first one. Or some hornbeam. But haven't cut anything just yet
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http://www.guaduabamboo.com/blog/comparing-mechanical-properties-of-bamboo-guadua-vs-moso
Bamboo stats research.
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http://ebooks.narotama.ac.id/files/Challenges,%20Opportunities%20and%20Solutions%20in%20Structural%20Engineering%20and%20Construction/8.16%20%20On%20characteristics%20of%20bamboo%20as%20structural%20materials.pdf
Madake comes in at about 100 in compression.
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What kind of cane wrapping is best to use on the Grip?
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Prairie Bowyer:I have 2 different widths of rattan which I use. 1 is wider at 3/16 inch and I use it for the arrow pass.Then a narrow one is 1/16 inch wide and it is great for wrapping the limbs.Both are flat on 1 side and come in long strands. Craft stores usually sell it for caning chairs.
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How do you put it on? Is it glued?