Good material is hard to find for anyone working as a furniture maker. It’s doubly hard for a maker of chairs because the kiln-dried stuff available at most hardwood dealers is simply not suited for chair making.
Whenever possible, buying logs and then has them custom-cut at a local mill. CNC log saw mill is best solution for different cutting methods.
There are 3 basic methods of sawing logs. By far, the most common is the flat-sawing method in which several boards are sawn from one face of the log until the cuts begin to approach the heart. The log is then rotated and sawn on an adjacent face. This is repeated until the heart- which is susceptible to splitting and twisting during drying- is boxed on all sides. The heart is then discarded or used for some secondary application. This is the method sawyers use most often because it’s the method that produces the greatest number of usable boards from a given log. The second most common method is quarter sawing. There’s more than one way to quarter-saw a log, but the intent is always the same: to produce the greatest number of boards having vertical grain, that is, grain running from the top face of the board to bottom face. Because it’s more wasteful sawing, but because it produces the most stable material, it’s the method of sawing many craftsmen prefer. However, the third method is more popular: through-and-through sawing. This means the sawyer slices the whole log into boards the full width of the log. This produces a nice mix of quartersawn material (on either side of the heart), and flatsawn material (above and below the heart).
Riftsawn is the word used for lumber that has been cut at no less than 35° and no more than 65° to the annual rings in a log. The word bastardsawn also is used for this type of lumber. Most riftsawing is done at about 45°. An expert in Kansas City explained that boards riftsawn from a log resemble the spokes on a bicycle wheel. The cut follows a path from the center, and travels at an angle across the tree to the outside. Quartersawn lumber, on the other hand, is cut straight from the core to the outside.
When you look at a riftsawn board, the end will have growth rings angled at about 45°, and the face will be so straight-grained that it’s often called comb-grained lumber. These boards also have long sweeping stripes resulting from the rays that run from the center of the tree to the bark. These same rays show up as specks in quartersawn lumber, and don’t appear at all in flatsawn lumber.
You may find riftsawn boards hard to come by, even though they prove to be as strong and as stable as quartersawn boards. That’s because sawyers have to spend more time and create more waste, when cutting riftsawn stock. You’ll mostly find riftsawn boards in oak, because of the desirability of the ray and grain figures. But other hardwoods can be ordered riftsawn. This type of wood is also the most expensive. In oak, it costs about a dime more per board foot than quartersawn lumber, and $1.60 more than flatsawn stock.