Yumi Build Along

[Hillbilly Deluxe]

     Thanks for all of the web-sites, they are all very helpful for anyone else planning on starting a yumi. These were essentially a majority of the info that I found as well on yumi construction which is why I thought I would do the build along.

     The web-site for Frank's where I got the boo is: www.franksupply.com they have all different sizes. I got the glue and core bamboo from: www.rudderbows.com they have a tremendous amount of bow and arrow making supplies and are very professional.
 
     Core:
     So for the core I decided to go with the oak. I got a 1x3 with really good grains and then chased a ring all the way down the back, then tapered the belly down to the widths I wanted. I was also thinking 3/8 might be a little thick. I will post the final dimensions I came up with when I get it sanded down and ready to glue up. I am shooting for around 10mm in the handle. I also used the 1x3 so that I could lay it out so that it had a little bit of bend to the right at the bottom, allowing the bow to spin in your hand when shot. I am also planning on heat tempering the core and belly this should help keep it from crysalizing. I am also thinking that with the exceptional length of the yumi that will help spread out some of the stress.

     Back / Belly:
     For the back I will not heat treat it and here are the dimensions; handle: 5mm, upper tip: 3mm, lower tip: 2mm. For the belly, once again I will temper it and the dimensions are as follows; 5mm the entire length.
     Here is some information I found on lengths from another web-site. I then put the English equivalent down for all of us Yankees.


Archer's Height         Arrow Length         Bow Length         
                             
150 cm-           59"       85 cm -        33.5"      Sansun-tsumari      212 cm   83.5"
                            
150-165 cm   65"      85-90 cm       35.5"      Namisun              221 cm   87"
                           
165-180 cm   71"      90-100 cm       39"      Nisun-nobi              227 cm   89.5"
                           
180-195 cm   77"      100-105 cm    41"      Yonsun-nobi      233 cm   91.7"
                           
195-205 cm   81"      105-110 cm    43"      Rokusun-nobi      239 cm   94"
                           
205 cm+           85"      110 cm+       45"      Hassun-nobi      245 cm   96.5"


     Hope all of this helps, I will post some pics. as well. I have to make some wedges and get some pieces for the syahs before I can glue it up bit I will post as soon as I can. Until then shoot straight!

[Hillbilly Deluxe]

Here is a pic. of the core after being roughed out, showing the grains.

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[Hillbilly Deluxe]

Reverse the words for the last two pics.

Here is the core looking down the belly and shows the curve to the right.

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[Hillbilly Deluxe]

Here are the end of the belly and back after they have been planed down using a belt sander and some 60 grit.

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[Hillbilly Deluxe]

   I just ordered some ebony for the tips, here is the web-site: www.exoticwood.biz they have a lot of selections and most of there stock is turning blanks, so I think that it will work excellent for this application. I think that I am going to do a black handle that fades into red with the black ebony tips again, then finish it all off with tru-oil. I think this will somewhat emulate a urishi finish.

[Hillbilly Deluxe]

Here is a picture of the bow after being glued. As well as a closer shot of the knocks partially finished.

I started bending it a little and it is definitely going to be a strong bow, which on one hand is good because that is what I was going for, but on the other hand I think that it may be a little too strong. I am going to try and train the bottom some more because almost all of the bend is in the upper limb right now. I think that I should have planed the lower tip to the same as the top.

I also planed the ends of the tips down to approx. 2mm for the length of the knock, as per another build along. I don't know that I would recomend this for a beginner because it make the tips a lot weaker and it is harder to bend to shape.

I was also wondering if anyone knew where to get a yumi string?

And also if anyone wanting to comment on my shaping feel free, I won't get my feelings hurt. I used the rope and wedge method and ended up with about 30cm of reflex when it was all said and done.

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[Hillbilly Deluxe]

Sorry I have not had time to post on this in a while, the core of the bow is too thick. lol  so i am going to grind off the belly and thin it down a little.  I had it bending nicely and enough to get it braced, however i think that it would have ended up a 150# bow which I thought was kind of excessive. I am also getting ready to go back to work in the rock-slides on I-40 back in TN / NC so i won't have as much time to work on it but will keep you updated.

[kurogane_84]

Id love to make a yumi one day, no one around my area has one  and i bet it would be sick to use, i have a 28 inch draw lol

[wasabi-kun]

There is a couple very good videos on how a traditional yumi bow is made. If you go straight across the bow from the back to the belly starting at one node you should end up in the middle  of two nodes, hope that makes sense. It will if you watch the youtube vids. And you'll need a specific shape for a mold when your curing the bow

[kurogane_84]

There is a couple very good videos on how a traditional yumi bow is made. If you go straight across the bow from the back to the belly starting at one node you should end up in the middle  of two nodes, hope that makes sense. It will if you watch the youtube vids. And you'll need a specific shape for a mold when your curing the bow

I agree there are alot on youtube about yumi bows