Eco-effective Choices in Sawing Methods
Grain pattern or figure is created when the log is sawn into lumber.
At what angle does the saw meet the growth rings? In flat- or plain-sawn hardwood boards, growth rings are parallel to the board's surface and create the flame-shaped, arch or cathedral grain pattern. Compared to the other methods, flat-sawing produces the most lumber and the widest lumber at the least cost.
Quarter-sawing is a slower and thus more expensive process than flat-sawing. The log actually is cut into quarters and sawn quarter by quarter. A single board is sawn from one face, then the next board is sawn from the opposite face and the sawing proceeds on alternate faces.
In quarter-sawn lumber, the growth rings are perpendicular to the board's broad face, producing a vertical and uniform grain pattern. This method yields fewer and narrower boards per log than flat-sawing, boosting their cost significantly.
The growth rings in rift-sawn lumber are at 30 to 60 degree angles to the board surface, producing vertical graining that is easily confused with quarter-sawn. Rift-sawn lumber also is available in limited quantities.
All lumber processing produces some quarter-sawn and some rift-sawn lumber. However, at least 95 percent of all hardwood lumber commercially produced in the U.S. is flat-sawn.
Sustainable design recognizes that no sawing method is superior and that all hardwood products will expand and contract as they reach balance with the relative humidity of their surroundings. Regardless of how they are sawn, all hardwood products should be stored and handled properly at the job site.
