Building a Wood Bow- The Grain
Building a bow out of wood is a time honored practice going back all the way to the paleolithic period of human civilization. Bows have been used to hunt game, fight wars and in modern days some interesting Olympic sport. With modern materials and compound pullies the humble wooden bow has been transformed in a durable high performing machine that little resembles the humble tool of 5000 years ago.
While modern bows are fabulous tools for hunting and amazing performers in target shooting they lack a certain life that can make them unappealing to people like me that like the traditional feel and handling of a wooden bow. While they may lack in performance and durability they can feel much more alive in your hands and can feel like a extension of your arm rather than a tool.
To build a bow out of wood you need to to know a few basic things about wood species, grain selection, shaping and tillering the bow. I will endeavor to cover all of these steps in a series of articles that will teach you how to make you own longbow out of common wood species.
Part 1- The Grain
Depending on who you ask the grain of the wood is the most important thing you need to know how to select when choosing wood for your bow. There are two different types of grain you need to pay attention to when selecting the wood for the bow.
End grain for bows make from split staves from tree trunks or branches
Long grain for bows made from sawn boards
Stave bows are made from either a single branch or trunk of a small tree or they are split from the trunk of a larger tree with multiple bows being made from one tree. On the right you can see examples of the kind of grain you are looking for when selecting the wood for your bow. The outer layers of the tree is called sapwood. Sapwood is typically the best wood for the back of the bow as it is better at taking tension when the bow is drawn. You also want to make sure that the wood is clear of knots in all parts of the stave that will be bending as a knot is typically a weak point in the wood. Bows can be made with wood that has knots and crooked grain but it take experience and skill when shaping and tillering the bow to not turn those into fatal defects. So until you get more experience it is best to steer away from wood with too much character.
What you are looking for in the end grain is tight even growth rings that show the wood is dense and strong. Growth rings that are spaced to widely or with clearly visible pores in the wood will typically not make a long lived bow.
Board bows like the name implies are made from a sawn board from a lumber yard. They can make excellent bows if treated right and you take care to select good grain. Now unlike stave bows you do not need to pay nearly as much attention to end grain but instead you need to pay more attention to how straight the long grain of the board is.
The board on the left is a perfect example of what you want to see when selecting a board bow. The grain is perfectly parallel from end to end and it doesn't leave the edge of the board at any time. The most common point of failure on a board bow is where the grain runs off the edge of the bow like depicted in the image on the right.
If you can find a board that has bow straight long grain and a good end grain than you have found a good piece of wood and you need to buy it right that second.
I hope that you found Part 1 of building a wood longbow useful and stay tuned for Parts 2 and 3.