Crushing strength is also an extremely important variable in “what makes a good bow wood”.
Plenty of species listed here aren’t typically even considered in the list of “secondary” bow woods given it will suffer compression fractures relatively easily.

do you think that Australian black wattle would make a good bow

I live in the highlands of PNG and recently bought a 6 foot long bow from an American expat. It is only about 35 pounds draw weight and I would like to back it with something to bring the weight up to at least 45, preferably 50-55. Any suggestions for a wood I could access here that would work well?

The foremost metric of bow performance is speed of cast. The speed of cast of a bow has a hard upper limit at the speed attained by the center-most point of the string during a dry-fire. Obviously, you don’t want to damage the bow, so the arrow should be massive enough in relation to the draw weight of the bow so as to keep the release speed of the arrow much slower than the dry-fire speed. The faster a bow is capable of dry-firing, the faster it can propel an arrow sufficiently massive so as to prevent the limbs from… Read more »

I am impressed by the response to my test entry “cedar”. I have an excellent Virginia Juniper in my front yard, and I disdain the practice of calling it and the Thuja plicata “red cedars”

Just from playing around in the yard I believe wild shrubs would make a good bow wood so I think i’ll make a full size bow to to see

Young’s modulus is determined by measuring short deflections under load. It is a constant which reflects a material’s inherent stiffness. Modulus of Rupture is measured at the final breaking point where the wood gives way under load regardless of the amount of bend before the breakage occurs. A bow needs to flex in a dramatic way, so while these two measurements are important, they can’t tell the whole story. A low stiffness wood like pear could be too brittle and woods with higher stiffness to breakage ratios like hickory and black locust could make excellent bows. Since stiffness is a… Read more »

Here is the post with file :) After seeing all the comments about the different ways to calculate the bow wood index I combined the two for a better overview. The difficult part is that even tho the calculations are based on the physical properties of the wood, things like heartwood/sapwood, interlocked grain, great compression strenght or the addition of a rawhide backing could alter these numbers significantly, which would mean that the number as calculated are not a 100% accurate in real life. A great example of this is juniper, the MOR/MOE *1000 gives 10.31 which is not to… Read more »

Hi there, After seeing all the comments about the different ways to calculate the bow wood index I combined the two for a better overview. The difficult part is that even tho the calculations are based on the physical properties of the wood, things like heartwood/sapwood, interlocked grain, great compression strenght or the addition of a rawhide backing could alter these numbers significantly, which would mean that the number as calculated are not a 100% accurate in real life. A great example of this is juniper, the MOR/MOE *1000 gives 10.31 which is not to bad, the MOR^2/MOE/dried weight gives… Read more »

MOR^2/MOE/dried weight
Higher result = lighter limbs for the same draw weight = faster and more efficient bow

Otzi, the 5000 year old ice man mummy found in Europe had two kinds of wood with him. He had Cornel and Verbinum. The pbs show (Nova) wasn’t clear on which type of wood was used for his bow and arrows and which was used as an axe handle.

A bow is a spring. How well does MOE describe a spring? An easily bent bow is a weak bow. Rubberbands bend easily. Stronger bows require more strength to bend then weaker bows. So, I doubt a low MOE would describe a good bow.

The MOE would be matched to the strength of the person using the bow to know if it the bow is too stiff for them to draw.

This is an interesting article. I agree with Eric regarding the ratio of MOR to MOE. Hickory is known to have an excellent MOR but it also has a very high MOE. That I believe explains its inferiority to osage or yew. Black locust has a slightly lower MOE than hickory but a similar MOR- again explaining its superiority. I have made bows from osage, muninga and chinaberry and of none of them took much set (plastic deformation). The only problem with just using this ratio is that it doesn’t take into account the fact that you still need the… Read more »