What trait of horn would make horn superior to wood?
The question came to my mind as I read about the comparative
experiment about water baffalo horn and osage orange wood from
Dr. Klopsteg's <Turkish Archery>, in which the result was that
the compressive strength of osage was nearly same as that of the horn.
(Although the book states that horn has the character that the osage
doesn't possess.)
Then, what traits of horn would make it superior to any other wood
as a material for bow? I have thought of its resilience, ability of absorbing
shock after the release, great compressive strength - osage might be
exceptional - . However, I wrote this question on this board, with the hope
of earning more precise and detailed explanation.
experiment about water baffalo horn and osage orange wood from
Dr. Klopsteg's <Turkish Archery>, in which the result was that
the compressive strength of osage was nearly same as that of the horn.
(Although the book states that horn has the character that the osage
doesn't possess.)
Then, what traits of horn would make it superior to any other wood
as a material for bow? I have thought of its resilience, ability of absorbing
shock after the release, great compressive strength - osage might be
exceptional - . However, I wrote this question on this board, with the hope
of earning more precise and detailed explanation.
Horn will compress farther and still be able to recover its shape. With wood, after a certain amount of compression, the cellular structure collapses and cannot recover. In practice this means you can bend horn more without destroying it.
Osage stores energy very well, but the main reason Klopsteg was interested in horn substitutes was the difficulty he had in getting horn in the USA.
Reading his discussion of the physics of the bow bending, he does not seem to appreciate how horn behaves under extreme flexure. He treats it as a simple material. Under minor deflections, horn does not perform that well and Klopsteg was designing bows to reduce the high stress concentrations that were typical of traditional composite bows.
Modern bowyers like Adam Karpowicz have achieved the same flexure of horn, wood and sinew bows that tradition bowyers had with similar results.
Osage stores energy very well, but the main reason Klopsteg was interested in horn substitutes was the difficulty he had in getting horn in the USA.
Reading his discussion of the physics of the bow bending, he does not seem to appreciate how horn behaves under extreme flexure. He treats it as a simple material. Under minor deflections, horn does not perform that well and Klopsteg was designing bows to reduce the high stress concentrations that were typical of traditional composite bows.
Modern bowyers like Adam Karpowicz have achieved the same flexure of horn, wood and sinew bows that tradition bowyers had with similar results.
I am trying to make a bow with materials that are readily available where I live. I have been on this project for about three years now. The wood is vine maple . The working part of each limb is 11". About 10" of the core at each end is steam bent on approx 4" radius to just past 90 degrees from the limbs with extra layers of wood laminated on for stiffness. Fire hardened layers are laminated onto the belly. I'm just curious to hear an experienced opinion on what I am trying to do, especially will this work with vine maple instead of horn?
I hope my description isn't too confusing. I tried to attach an image but kept getting an error message.
Thanks,
- Jon
I hope my description isn't too confusing. I tried to attach an image but kept getting an error message.
Thanks,
- Jon
The compression strength of wood is about 1.25 kilograms per millimeter, for water buffalo horns it is about 13 kilogrames per millimeter. Big difference!!
Same as sinew on bow back, the sinew has a tensile strength approching 20 kilograms per millimeter, that is about four times the feasible stress range of most appropriate wood(5 kilograms per millimeter). (refer to Scientific American, issue January 1985.)
This is why hornbows are far superior then wood bows.
Same as sinew on bow back, the sinew has a tensile strength approching 20 kilograms per millimeter, that is about four times the feasible stress range of most appropriate wood(5 kilograms per millimeter). (refer to Scientific American, issue January 1985.)
This is why hornbows are far superior then wood bows.