Korean horn bow dimentions

[Jakesnyder]

I know traditionally they used a bamboo core. I've watched some videos and it doesnt look that thick like maybe a quarter inch thick. Is that about right? Node placement is also a concern correct? Should there be one in the center of the handle and then wherever the others fall?

[bownarra]

Ideally no nodes in the working limb.
The thickness of the core tapers from handle to tips.
A Korean bow is very hard to get right on your first go. Remember the taper must be nigh on perfert when everything is glued together as you have very little room to tiller.

[Jakesnyder]

What would be a better style to start with? I'm struggling to find core material other than bamboo...thanks!

[bownarra]

No problem. Yes I understand on the core material front...
You can use boo on any style of hornbow. I would suggest maybe a Magyar style bow with reduced handle reflex for better energy storage. Basically  the design is straight bending limbs spliced to a handle section. Length of bending section is normally around 12 inches. Then syhias/outerlimbs (mildly reflexed) of around 14 inches spliced onto ends of the bending limbs.
I've made a couple like this, they are easy to tiller and good performers. 

[Jakesnyder]

Couple more questions... so the bamboo I got, once worked down will be right around a quarter inch thick. I'm guessing the outside of the bamboo will be the back of the core and the inside will be the belly of it? Does the bamboo need to be totally flat where the sinew will be applied? Or is it ok to have a slight crown? Also thickness taper it and width taper it?
I got 11 inches in between nodes. Should I situate the nodes partway down the v splice to get a 12inches? Is 12inches including cutting in the v splice or not including it at all?
Thanks for your help!

[bownarra]

The outside of the boo should be the belly of the core. A crown is no problem on the back of the assembled core - indeed most hornbows are built this way. The thick sinew 'edges' help the bow.
Thickness and width taper are established once the horn is glued to the assembled core. Unfortunately this is done by feel so I have no definite numbers for you.
If you can get 33mm width in the main bending section then taper to around 27mm where the tips are spliced.
Yes situate the nodes in the v-splice. Yes the 12 inches includes the splices. Handle splice should be 4 - 5 inches and tips 2 1/2 to 3".

[Jakesnyder]

Thanks for the help bownarra!
So as I glue up the horn to the boo and clamp it down will the horn pull up on the sides to fit the crown of the boo? After the horn is glued up and dried how much can I stress the bow to get the tiller right before sinewing?
Also does it matter about the grain orientation for the syhias? As long as its strait grain the whole way through it. Do you know what I mean? If your looking at side of the syhias it would be bias grain(you could see the growth rings) and the back side of the bow you would have a solid growth ring the whole way up the syiah?

[bownarra]

No problem
No make the core/horn joint flat. If you try to bend the horn it will get belly cracks. It can be done but I wouldn't recommend it to begin with.
Good question - not much but you can bend it backwards and from that shape you can determine the bending sections taper.
No the grain can be any orientation for the tips as long as it runs the full length. Remember you can also laminate them from thin pieces.

[Jakesnyder]

Can I completely flatten my bamboo? I would have to plane the outside of the bamboo to make the crown flat to meet with the horn. Is this an issue? So can I remove material from both sides of it to get it completely flat? Its thick enough to do that.

[bownarra]

Yes no problem to flatten completely.
Bear in mind that when it comes to gluing the horn you want the core as stiff as possible because it acts as a form for the softer horn. Eg. the horn will follow the shape of the core and it is easy to twist the core during glue up.
You can also prepare the core then glue on a sacrificial piece of wood to the back of the core to stiffen it, glue the horn, then remove this piece when you come to shape the core prior to sinewing.

[Jakesnyder]

Now at the tip of the syhias where the string knock will be, would 3/16" thick and 3/4" wide be ok for them? I've never seen dimensions of any kind of horn bow so I'm kind of running blind with dimensions. Im just kind of need a starting point.

[DC]

The tips on mine are just under 1/2" wide and 3/4" thick.  I got that dimension from Adams book (10 x 17mm at the nock)

[Jakesnyder]

I'm going to take a shot in the dark but I'm guessing this boo is  not any good. Can you see the bug damage? Am I correct?

[bownarra]

Yes I can see it and unless you are 100% certain it won't be in the finished bow best to throw them away.
£/4 wide for the tips is ok as you will be narrowing them later.

[Jakesnyder]

Ok so I got some sugar maple that might make a good core. The only issue is it's not 100 percent seasoned yet. It's been drying inside for about a month. Since these take so long to make does it need to be totally seasoned to start working with it?