Why we use hickory
Chart courtesy of www.customcountrywoods.com
Let's talk about wood. Two primary qualities come into play in picking out the proper axe handle; hardness and flexibility. In this Janka Wood Hardness chart, you can see the hardness of some common woods worldwide.
This chart shows Ebony to be one of the hardest woods in the world, so does this mean it would make the best axe handle? Far from it! Hardness directly correlates to brittleness. The best thing an ebony handle would be is a wall hanger! Our axe and tool handles must have a high hardness rating and be flexible and durable. This perfect marriage of traits makes only a few wood species ideal for the axe and tool handle. Typical candidates are hickory, ash, elm, oak, osage orange, maple, and beech.
Sometimes, these woods are primarily used depending on your region. Hickory handles are widely used internationally, but the tree is native to the eastern US. In contrast, ash/elm is domestic in Europe. We use kiln-dried hickory at the Hoffman shop for its sweet combination of hardness, flexibility, and availability. We're fortunate to be located in the heart of our country's hickory forests.
There are different species of hickory trees, and each tree of its species can be different just depending on environmental factors. Still, overall, hickory also has a very tight grain structure, which prevents water from entering the wood quickly. A long soak in oil can penetrate the wood and help prevent water damage.
The below chart compares the hardness to the bending strength of different North American wood species. Of the species shown, hickory is a clear winner, with ash, hard maple, and white oak competing for second place. If osage orange were listed it would outcompete even the hickory. Unfortunately, osage orange wood isn't cost-effective to use regularly. Still, we do offer it from time to time as we can get the material. Interestingly, cherry has a relatively high bending strength but isn't paired with high hardness.
Wood species plays a significant role in whether your handle holds up, but it's not the end all. The geometry and length of the handle contribute a lot to this. Obviously, the longer the handle, the more demanding it will be on the wood. This means that unconventional woods can be used on shorter handles and still hold up just fine. On long handles, the thickness and transitional curves play a significant role in the longevity of your handle. Ironically, if your handle is too thick, it's more likely to break!
The thickness of your handle plays critical roles in not only the strength of your handle but also the technique that it's swung and the wear and tear on your body, but that's a topic for another time. If your handle is too thick, it will be more rigid, and as we know, an object that is rigid and cannot flex is more prone to breaking. Take skyscrapers, for instance; they're designed to sway in high winds rather than tumbling down. If your handle is thin enough, it will flex and spring back to shape, so this factor alone can play a role in your handle strength whether you choose a suitable species of wood or not.
Lastly, the transitional curves mentioned above play a role. By transitional curves, I am referring to the geometry of the eye into the shoulder of the handle and down into the midsection. If there are any abrupt shoulders, sharp corners, or tight radii in this area, you may cause a stress point and increase the chances of a break. While a little off-topic, I hope this extra information can show that choosing the best wood available makes your handle better, but it will only sometimes mean you have a long-lasting handle. It can also be a good choice, even if you choose a wood without high flexibility or hardness.
Chart courtesy of www.workshopcompanion.com