The Balance of Bend and Break
Finding the perfect wood for a bow is a unique challenge. You aren’t just looking for “strength” in the way a floor joist needs it; you need a material that can survive a deep bend without snapping. In the simplest terms, a great bow wood needs to bend easily but refuse to break.
To evaluate this scientifically, we look at two specific measurements: MOR and MOE.
1. Modulus of Rupture (MOR): The “Break” Factor
- Think of MOR as the wood’s ultimate limit. It measures how much force a piece of wood can handle before it actually fails or ruptures.
- The Goal: The higher the number, the tougher the wood is to break.
2. Modulus of Elasticity (MOE): The “Stiffness” Factor
- MOE measures the wood’s stiffness, or how much it resists being bent. It is technically the ratio of the stress applied to the deformation (strain) the wood exhibits.
- This number is usually calculated at 12% moisture content and applies specifically to the strength along the grain.
- The Goal: In archery, a lower MOE is often better because it means the wood is less “stubborn” and will flex more naturally.
The “Golden Ratio” for Archers
According to classic research in Archery: The Technical Side (Hickman et al. 1947), the best bow materials combine high bending strength (MOR) with a relatively low stiffness (MOE).
When you have a wood that stores high energy under large deformation—rather than just being stiff and brittle—you get a more efficient transfer of energy from the limbs to the arrow. For example, while hickory is incredibly stiff (MOE of 2,160,000), its massive breaking strength (MOR) is what makes it a legendary bow wood.
Summary
When you’re scanning wood property charts, look for species where the MOR is high but the MOE remains manageable. You want a limb that is willing to work with you during the draw, but has the backbone to survive the shot.
Bear in mind that the chart below only focuses on woods that we have available in our area or those that we most often stock in our shop. To view a complete list, check out the woods database.
| Bow Wood Mechanical Properties – Bending Branch Bow Woods Comparison | ||||
| All values measured at 12% moisture content. | ||||
| Common Name | Scientific Name | MOR (psi) | MOE (psi) | Bow Index |
| Osage Orange | Maclura pomifera | 20,200 | 1,689,000 | 11.96 |
| Actionboo [reference] |
engineered wood product
|
17,400 | 1,600,000 | 10.87 |
| Bitternut Hickory | Carya cordiformis | 17,200 | 1,790,000 | 9.61 |
| Red Elm | Ulmus rubra | 14,300 | 1,490,000 | 9.60 |
| Black Locust | Robinia pseudoacacia | 19,400 | 2,050,000 | 9.46 |
| Eastern Hophornbeam* | Ostrya virginiana | 15,500 | 1,640,000 | 9.45 |
| American Elm | Ulmus americana | 12,000 | 1,340,000 | 8.96 |
| Black Walnut | Juglans nigra | 14,600 | 1,680,000 | 8.69 |
| Sugar Maple | Acer saccharum | 15,800 | 1,830,000 | 8.63 |
| Eastern Red Cedar | Juniperus virginiana | 8,800 | 1,020,000 | 8.63 |
| White Ash | Fraxinus americana | 15,000 | 1,740,000 | 8.62 |
| Jatoba | Hymenaea courbaril | 23,430 | 2,745,000 | 8.54 |
| Black Cherry | Prunus serotina | 12,300 | 1,490,000 | 8.26 |
| Northern White Cedar | Thuja occidentalis | 6,500 | 800,000 | 8.13 |
| Black Ash | Fraxinus nigra | 12,600 | 1,600,000 | 7.88 |
| Eastern Hemlock | Tsuga canadensis | 8,900 | 1,200,000 | 7.42 |
| Tamarack | Larix laricina | 11,600 | 1,590,000 | 7.30 |
*In my area, people call this species Ironwood (Ostrya virginiana).
If you feel like we are missing an important species of limb wood, please let us know.