This allows for the saw itself to be  very elastic and there is no need to constrain it and stretch the blade, as it will stretch naturally when you pull it. It appears that with 5 strips the bow may be too thick. The grip with the rattan is not in the middle of the bow. Sections have to intersect evenly, as per the diagram (left image): For the inside face, the same rule applies, but note how the sections are aligned with the front face – they are in the middle of the section. Change ), You are commenting using your Twitter account. The handle on a Yumi is well below the center. Then the core is a laminate of strips of bamboo and hardwood in different configurations. […] I want to heat treat the bamboo to much lighter color, say “coffee with milk”. But the laminated core is very difficult for me to do. The goal is to achieve nice and brown bamboo,but not burned throughout. Again, the blade is VERY sharp (so don’t swipe it with your thumb to clean it …). Overall experience is rather disappointing, this set up is not good for cutting long bamboo planks easy. Pushing down actually makes the cutting much harder as the teeth bit deep into bamboo. soon I will figure it out and update it** Required Items to Build the Yumi … I added an alignment block and using this I cut these planks within 30 mins. It is not only the length that makes the Yumi … Wielded and inspired by the Samurai warrior archers of Japan, the Grayvn Japanese Yumi bow is crafted from Bamboo and hickory in the original design and scaled to 72″. The string is made of linen, the slight recurves are wrapped with thin buckskin, the handle is wrapped with a thicker buckskin, buckskin is naturally tanned with fat. Bamboo plank is naturally divided into sections, so trimming down 2.5 m long plank is not a daunting task as you can see the progress with every section completed. Right after heat treating bamboo is very brittle. This would work and would be safe so it would be a better option. mijn hobby 1,110 1 Traditionally, a Yumi is made from bamboo, as it is a flexible, yet tough wood. However, these high quality Nibe … The Japanese used a bow very similar to the English longbow. Step 2. It needs to be set up correctly, as it can bite too deep and ruin the strip. Now the bow is soft and supple and you can bend it into shape. Note for the future – the radius of the pole is important as well…. Modern use of the Yumi Bow is known as Kyudo, or "Way of the Bow." Always cut. Better for what?? Yumi making: Phase 3: Preparing bow parts. Required Items to Build the Yumi Bow: Beefalo Wool (1); **Originally would be leather, but it's missing in the game** Boards (2); Rope (2); **OBS: Yet I don't know how to create a bamboo plant, that will be how to build it for now! 12.5mm –> 10mm (- 2 x 2.5mm) –> 47.5mm The core in-between contributes nothing to the bow’s power and really only exists to keep the front and back apart, it’s important to minimise its mass so that as much as possible of the bow’s energy goes into the arrow, rather than being wasted in moving the bow. Nibe Yumi A Nibe Yumi is a bow that uses an adhesive called “nibe” which is made by slicing deer skin and boiling it for two days. So… Using kanna to shave that skin is not the best idea. Thank you so much. There are 7 m long poles there that may fit the profile, and I could get them cut at the warehouse to the required length and size. Acquire a piece of flexible bamboo about 10 feet in length. Always wear a respiratory mask and eye protection, as sawdust can be harmful. The force of the bow is generated by the bits of wood nearest the front and the back. @ 150 cm there is a grip that has a shaping insert that makes the grip rounder. Take your time,  measure with calipers, make many small, shallow (easy) cuts. This graph shows nicely the outline of the bow – it is thinner towards the ends, and the upper end is longer / thinner that the lower one. Preparing yew hardwood for sides of the core / bow. This process is also common in European bow making, and for long distance shooting bows it is considered a “silver bullet”: it eliminates the moisture thus making the wood / limbs lighter and quicker; it hardens the wood so it adds power to the bow; it allows for corrections to the shape of the bow. I’m confused by this design, because it doesn’t seem to fit with the physics of bows. Under the sekiita there is a supporting rattan wrapping. He has worked on publications such as "The Liberty," "Chrome," "DIT News," "The Kippure," "Ausblick," "Backpacker Magazine" and ciNews, holding such roles as section editor, copy editor, reporter and layout designer. Also the overall thickness is affected by the core thickness, not by the faces thickness.So the faces have the same thickness along the whole length, which means that the core thickness needs to be adjusted before gluing the whole bow. Has anyone made a Yumi bow here? It will cut through the joints but they have to be trimmed down first.The “skin” of bamboo, the external and even more, the internal, is hard and somewhat siliconised. For the planing, kanna plane is a blessing. Yumi are not particularly difficult bows to make, especially compared with laminated composite bows. I wouldn’t want it to start cracking and falling apart inside a finished bow. I could still match what I have and achieve the required sequence of sections on both sides, but the nodes that define where the grip is would probably end up being a bit too high, or I would have to make the grip around some nodes, which is not ideal. Mar 16, 2019 - In general, the yumi bow consists of two faces made out of bamboo, the front face (that is on the external side of the bow, closer to the target) and the back face (the one closer to the archer). You can also use yew or hickory, but you may want to use bamboo for the sake of authenticity. 12.5mm –> 10mm (- 2 x 2.5mm) –>47.5mm Above the grip there is a decorative rattan (1.8 cm), below it there is the arrow protecting rattan (Yasurido – 10 cm), then the grip itself – 9 cm, and below the grip there is the decorative rattan again (1.8 cm). I’ll try the sander to even them out, and then they should be ready for heat treating. The bow should be around ¾-inch wide and ½-inch thick all over. Yabusame is the Japanese practice of mounted archery. The thickness should be about 3 – 4 mm as I need to pack five of them + two strips of side hardwood into the core, and the overall width of the whole thing should fit in hand, so should not be more than 4.5 cm. Here is how the trimming down process should look like: I’m starting with from the third picture as my planks are already pre-cut: But they seem to be taken from much thicker bamboo pole, which may affect how wide the final plank will be: So, this may be a problem, maybe the final bow will be “flatter” – I’m not sure if I can shave the bamboo to make it round enough without it becoming weaker. The draw strength and size of the yumi bow should be adequately precise for the user and its standard length should be around eighty-seven inches which is based on the average height of a Japanese individual which is about 150 … 8 - The Yumi at full draw showing the 65 cents relationship between the arm and the bow. – raw bamboo is good for tension and forms the outside face, while heat-treated bamboo is good for compression and forms the inside face. eHow may earn compensation through affiliate links in this story. Take your time, clearing the joint takes as much time as clearing the section. Soak the bow in boiling water for around 30 minutes. Eventhough I prefer short bows, I like this style of “primitive” yumi, due to its asymmetry it makes you feel to shoot a somewhat shorter bow … Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. I’ve measured and inspected the yew strips that I have, and selected the best one (no white wood, no knots etc.). I don’t want to destroy the planks I’ve spent so many hours on by over heating, so I have made a test run with similar thickness bamboo plank over the period of 15 minutes. Each minute I inserted the bamboo 1 cm deeper, so I could see what effect over time heat treating has on bamboo. While the deviation is not large (~5 mm) it is still visible on the narrow planks that I have , and on the whole length of the plank it is significant. the joints  (or “knees”) are the hardest part to cut. 5mm –> 4mm (- 5 x 1mm) –> 42.5mm. Also the saw teeth are a bit like cat’s paws, so they bite into the wood when you pull, which means there is no need to press down hard on the saw to get a cut. It is the dark brown attachment below: There are also other “attachments” – elements that are not part of the bow body (not glued permanently) and can be replaced, like the grip leather, grip insert, bamboo wrappings. Easy in theory, in practice the jig saw blade bends on any pressure and goes of of the center line. Against the grain is becomes very brittle and breaks off little chips instead of leaving a nice surface. It needs to be set up correctly to work with ease. So on some areas of the plank I had to plane in the opposite direction. There are several theories about why this is, but the main ones are that the bow was designed to be shot from horseback and that the wood was thicker at the bottom and makers thus had to overcompensate with a longer tip.