Mechanical properties for woods.

[Thorvald]

Hi.

It is relative easy to find mechanical properties for woods that can be used in building construction. But I would like to find mechanical properties for woods that can be used in bow building. That would be properties for woods such as hard rock maple, yew, bamboo, cocobolo, bolivian rosewood, bocote and such. And an additional question is: What material properties determines if a wood is good as a spring, i.e. when it is bent and released it returns to it's rest position as fast as possible.

Below is some examples of woods from a book I have.

By the way - I think "Pokkenholt" is Lignum Vitae.

 

[Studiot]

You might find more help in these specialist places.

http://www.archery-interchange.net/forum/

http://www.archery-forum.com/

http://sagittarius.student.utwente.nl/bb/

 

[Thorvald]

Maybe, but I doubt it. I am on AIUK (the first link). The two other fora is rather unknown to me. But in general archers and even bow builders (as far as I know) doesn't know the mechanical properties of the woods they are using. Because they go by experience: If the limb is so and so thick, and made of this wood, it gives a draw force of XX lbs. But I'd rather like to go the more scientific route. The closest to something that I might be able to use is this: (Well couldn't get the link, the site didn't work. But it is at www.binghamprojects.com. I have attached it. But this is for the bow as a whole and probably with laminations and with fibreglass. Also it doesn't mention what bow woods the chart is based on.

 

[dipstik]

modulus pertains to springiness (hookes law) and tensile strength, or even better, flexural rupture will give u an idea of how much it can bend.

I think ASTM D143 has proceedures to determine these values, so u might want to use that as a google scholar search termgood luck

 

[alphy]

Thank you for your question. I can understand your interest in finding mechanical properties for woods specifically for bow building. While there are many resources available for general mechanical properties of woods used in construction, it may be more challenging to find specific properties for the types of woods you mentioned.

Firstly, it is important to note that the mechanical properties of a wood can vary depending on factors such as species, growth conditions, and processing methods. Therefore, it is best to consult with a professional in the field of bow building or a wood expert who may have more specific information on the mechanical properties of the woods you are interested in. They may also be able to provide you with data or resources that are more tailored to your needs.

In general, the key mechanical properties that determine if a wood is suitable for use in a bow are its stiffness, hardness, and density. Stiffness, also known as modulus of elasticity, refers to a material's resistance to deformation under stress. Hardness, on the other hand, is a measure of a material's resistance to indentation or scratching. Density is the mass per unit volume of a material and can also affect its overall strength and performance.

Some of the woods you mentioned, such as hard rock maple and yew, are known for their high stiffness and density, making them popular choices for bow building. Bamboo, on the other hand, has a unique structure that allows it to be both strong and flexible, making it a popular choice for bows in some cultures.

In terms of determining if a wood is good as a spring, there are a few other properties to consider. These include the wood's strength and elasticity, as well as its ability to resist fatigue and creep (deformation over time). Again, the specific properties of each wood will vary, so it is best to consult with an expert in the field.

I am not familiar with the term "Pokkenholt," but if it is indeed Lignum Vitae, then it is known for its high strength and hardness, making it a popular wood for making tools and bearings.

In conclusion, while there may not be readily available data on the mechanical properties of woods specifically for bow building, there are experts and resources that can provide you with more tailored information. It is also important to keep in mind that the properties of a wood can vary and may change depending on the specific application and conditions. I hope this helps and I wish you all the best in your bow building endeavors