Preparing horns

Chaka Zulu wrote:

How do you get from a horn to horn strips? I've got a strip cut from the horn but no idea how to make it into flat smooth belly piece. Rasp, steam, boil? Something else?

Pretty much all of the above. The Korean bowyer will cut, boil, grind, groove and glue-size before the strips are ever applied to the core. After that, lots and lots of rasping. Well, that's the Reader's Digest version, anyway...

Right, so boil them until they flatten and then rasp the thickness down?

i'd like to know more, too!

I'm new to ATARN, and new to composites, but i'm not new to bowmaking. I've got a few pairs of horn, a shop, and i've been reading through the forum looking for information.

I guess the plan is to just work at it and learn by doing, like i always do. But if anyone's got a good link for me, i'd sure appreciate it. Thanks

Cutting from raw horn is done like thisLike this:
http://www.atarn.org/islamic/turkish_bo ... g_horn.htm

Your target thickness after rasping is 3-4mm. It should be possible to heat the horn and press it flat after that.

These are the horns i just received. The one i'm working on looks like i'll get strips about 21" long. The next pair is shorter, and the strips from it might be 18" long, or 17". However, the shorter pair is very deeply ridged, and i wonder how thick a lam i'll end up with. Farrier's rasp turns out to be great with this material, and the cabinet scraper too. I'm starting to see how this will work. It's like a homogenous material? With no growth rings? I think i can get 4 mm out of the tips, but they will only be 5/8 wide at that point.

Thanks for looking.


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I used horns that looked the no different than the ones pictured above and reduced them down to 5mm strips all with a belt sander with a 50 grit belt. It is not traditional but the belt sander made quick work. I set up the belt sander outside with a box fan blowing the dust away from me, it worked very well. I then boiled the horn strips for 10 min and clamped each strip flat until they cooled. Adam is correct in his book when he says you can "feel" fractions of a millimeter. I again worked the horn down to 3mm on the belt sander, checking the thickness with a caliper every so often.

Today I?ll begin posting a "How to make a hornbow build along" on my blog: http://redhawk55.wordpress.com
It will be picture heavy and includes the making of a hornbow for a 150lbs- crossbow too. Vol. 1 is focused on selecting, cutting and preparing the horn.

Michael

except push bamboo arrows to this world,i plan to push horn strips too

To Radius:

the horn will be the other way round on the bow. TIPS meet in the MIDDLE!

Peter

But the tips are so narrow? i'm wondering how wide a strip i can get from these.

the thinner tips go in the middle,the handle is thinner and the stiffer tips in the middle make a better bow,you get more length out of the horn as well.That is the way it has been done and should be done.

Radius,
The horn has to fit the bow dimensions. How close to the tip can be made usable depends on the width at the grip. Some will obviously be lost and the thin horn wall at the root end can also determine the length of the finished strip. If you buy larger than you need that should prevent any disappointment.
Oh, you have to be careful with those cracked areas at the natural ribs and crevices as well, they can run quite deep into the horn.
As you sand the horn down you will notice that there are growth rings, these can make an attractive pattern on the finished article

I made the outer surface flat first eg. got rid of the ridges and grooves. When you have this surface flat cut to somewhere near the width amd go from there. Good luck

i've got one of the pairs sawn into 2 strips each, and ready to flatten.

The other pair is very deeply ridged. I don't think i'll get 2 pairs from them. But i'm going to wait until i see what this stuff is like to work with before tackling the other pair.

Sorry for the delay, but my article Hornbow Vol.1 is out now on http://redhawk55.wordpress.com focused on selecting and cutting horn.
Michael

You used word "Modulus of elasticity", but what you really meant was modulus of rupture.

Modulus of elasticty (moe, elastic modulus) does not tell how far you can bend, but how much force it requires, thus it is the stifness, not the elasticity.

That?s a translation- failure. I searched LEO for the English term for e- modulus and ended up by "modulus of elasticity", what makes me wonder.
I can?t find another translation. Modulus of rupture is it.
Thanks, jkekoni, I?ll adjust it next volume.
Michael

You searched for the wrong thing. It should be compressive strength or Druckfestigkeit in german.

I am actually wondering why the word modulus is used in this context at all. It does not make sense.

What is actually the import thing with the horn is not is ultimate strength, but for how far the deformation is reversible (elastic). I think that is called modulus of resilience.

Daniel

Yes, that?s what I was wondering. Resilience is it.
Usally I?m using this term for to clear up the main advantage of horn in bowery.
I guess jkekoni and Daniel T, you?re engineers?
Michael

Yes. Msc Engineering, Datacom programming Major and Digital signal processing minor, so unfortunately I have no professional studies in material sciences, mechanical engineering, or biology.

(Working as software designer mostly related to Mobile phone industry.)

No, I'm a physicist, but I know a few general things about mechanics.

hello, does anyone have pictures of horn grooving tools, or any ideas on easy ways to groove horn? By the way how was this done in the past? I am guessing it was probably scraped out line by line.

Amaguk, next Monday I?ll post the next volume of the making of hornbows on my blog focused on grooving with a very "primitive" but effective grooving tool.
Go to: http://redhawk55.wordpress.com.
Michael