Primitive Archer

Main Discussion Area => Bows => Topic started by: FilipT on February 24, 2017, 09:46:36 am

Title: Yumi self bow?
Post by: FilipT on February 24, 2017, 09:46:36 am
Anyone attempted to make Japanese samurai Yumi bow, but from one piece of wood? Traditionally its made from laminated bamboo, with each layer actually bound, not so much glued to each other.

It is probably largest type of bow and famous for its asymmetric profile.

Here is picture:

(http://begaarchers.com.au/wp-content/uploads/2012/04/016.jpg)
Title: Re: Yumi self bow?
Post by: PatM on February 24, 2017, 09:50:30 am
No but logically you can duplicate the shape and curves with a good piece of wood and dry heat. They were definitely glued together. Any binding was to reinforce glue joints, not replace them.
Title: Re: Yumi self bow?
Post by: Urufu_Shinjiro on February 24, 2017, 10:46:58 am
You should be able to reproduce the shape but I suspect the performance and characteristics will be completely different. The shape of the Yumi is created during glue up of the laminates, so the whole thing is sort of perry reflexed and afaik the tillering is all done by the shaping of the laminates and once it's glued up the only tillering is small heat corrections (again, this is AFIAK). Getting a self bow the have the same unstrung profile and braced profile may be possible but will likely be more difficult that just making a bamboo laminate Yumi. Of course I'm not really a bowyer just going off what I've learned here and what I know about Yumis (used to be fascinated with them) so I may be way off base. Like many others on this site I agree with the "hey, try it and let us know" philosophy.
Title: Re: Yumi self bow?
Post by: mullet on February 24, 2017, 11:50:26 am
I thought they were made with 5 pieces of bamboo and maple laminated?
Title: Re: Yumi self bow?
Post by: PEARL DRUMS on February 24, 2017, 12:01:15 pm
I would think if you tried to replicate that with solid wood the balance would be just short of miserable and uncomfortable. The boo makes that whacky design go.
Title: Re: Yumi self bow?
Post by: PatM on February 24, 2017, 12:20:48 pm
I think if you could get the shape and mass the same the performance would be hard to differentiate but I'm sure purists would impart mystical extra qualities. ;)
Title: Re: Yumi self bow?
Post by: Urufu_Shinjiro on February 24, 2017, 12:40:13 pm
I thought they were made with 5 pieces of bamboo and maple laminated?

Like most things Japanese they had various schools of design for Yumi (and a long name for each variation, lol), some are as simple as two or three horizontal flat bamboo strips, some as complicated as a central square cross section with various other square to rectangular sections in various patterns etc, some with or without a wood layer etc, lol.

Like this cross section (http://ecoecoman.com/kyudo/item/image/take07.gif) is a style called yon sun nobi I believe. The dark sections on the outside of the core are hardwood, the rest are bamboo.
Title: Re: Yumi self bow?
Post by: FilipT on February 24, 2017, 01:09:53 pm
Like I thought, its more of a wishful dream. Seems like I am gonna be samurai with an European longbow haha
Title: Re: Yumi self bow?
Post by: Tree_Ninja on February 24, 2017, 02:00:27 pm
 
Quote
   Like I thought, its more of a wishful dream. Seems like I am gonna be samurai with an European longbow haha


Pfft. Samurai oppressors. >:D

 Do you have a horse too? The Yumi's Design was mostly for mounted applications.

Just go ronin and get a horn-bow in battle from Kublai Khan.

Or ditch the waka , shorten the katana and get some shurikens.

Sorry off topic.  ;D
Title: Re: Yumi self bow?
Post by: EdwardS on February 24, 2017, 03:43:13 pm
You're thinking of a hankyo yumi.  Shorter horseback version of the same bow.  A boo backed and bellied bow with a maple core would do it for one of those.I shoot yumi too, and I am building my own sword, so I get the appeal.  Nothing else has the draw length or equivalent arrow speed for the buck.  Makes me wish for the days I spent shooting one.

There are the PVC versions of the hankyu that people make that might satisfy you if all you want is the bow to draw that far, but otherwise it's bamboo and ropes and wedges.

Jaap Koppedrayer would be an excellent source of information on this.  He hosts bowbuilding courses from time to time as I remember.  Has videos available to purchase as well.

I shoot a short Koreanish bow for most things like that.  I'm very interested in a Manchu bow for myself.
Title: Re: Yumi self bow?
Post by: FilipT on February 24, 2017, 04:59:01 pm
What kind of sword? I am waiting for steel, gonna make two witcher inspired swords, one blunt for practice, and other for cutting.
Title: Re: Yumi self bow?
Post by: loon on February 24, 2017, 06:35:07 pm
I guess Jaap Koppedrayer makes some simpler ones without so many laminations as well as the more complex ones? Not sure.

Those things are so reflexed.. but yes.

I guess you could call some of these yumi selfbows:

Code: [Select]
https://redhawk55.wordpress.com/2010/10/13/asymmetrical-bow-designs-vol-3-maruki-yumi-made-of-juniper/

https://redhawk55.wordpress.com/2010/08/22/asymmetrical-bow-designs-vol-1-what%C2%B4s-harmony/

(my adblocker and privacy badger are blocking a bunch of stuff in his site, so I'm not making them clickable...)
Title: Re: Yumi self bow?
Post by: EdwardS on February 24, 2017, 08:36:47 pm
Making a tachi, curved handle and all.  Had the blade forhed in Longquan, City of Swords.  Beautiful thing, real differential temper and all.  Need some chisels to start on a handle.
Title: Re: Yumi self bow?
Post by: FilipT on February 25, 2017, 02:55:54 am
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