Quarter sawn

Quarter sawing is a type of cut in the rip-sawing of logs into lumber. The resulting lumber is called quartersawn (quarter-sawn), quartered, and radially-sawn. There is widespread confusion between the terms quartersawn and riftsawn with both words defined with opposite meanings and as synonyms.

Quarter-sawn boards have greater stability of form and size with less cupping, shrinkage across the width, shake and splitting, and other good qualities. In some woods, such as oak, the grain produces a decorative effect which shows a prominent ray fleck and sapele is likely to produce a ribbon figure.

When boards are cut from a log they are usually rip cut along the length (axis) of the log. This can be done in three ways: plain-sawing (most common, also known as flat-sawn, bastard-sawn, through and through, and tangent-sawn), quarter-sawing (less common), or rift sawing (rare).

In flat-sawing the log is passed through the blade cutting off plank after plank without changing the orientation of the blade or log. The resulting planks have different annual ring orientations when viewed from the end. The relative angle that form the rings and the surface go from almost zero degrees in the external planks to almost ninety degrees at the core of the log.

Quarter sawing gets its name from the fact that the log is first quartered lengthwise, resulting in wedges with a right angle ending at approximately the center of the original log. Each quarter is then cut separately by tipping it up on its point and sawing boards successively along the axis. That results in boards with the annual rings mostly perpendicular to the faces. Quarter sawing yields boards with straight striped grain lines, greater stability than flatsawn wood, and a distinctive ray and fleck figure. It also yields narrower boards, because the log is first quartered, which is more wasteful.

Quartersawn boards can also be produced by cutting a board from one flat face of the quarter, flipping the wedge onto the other flat face to cut the next board, and so on.

Quarter sawing is sometimes confused with the much less common "rift sawing." In quartersawn wood, only the center board of the quarter-log is cut with the growth rings truly perpendicular to the surface of the board. The smaller boards cut from either side have grain increasingly skewed. Riftsawn wood has every board cut along a radius of the original log, so each board has a perpendicular grain, with the growth rings oriented at right angles to the surface of the board. However, since this produces a great deal of waste (in the form of wedge-shaped scraps from between the boards) rift-sawing is very seldom used. Quartersawn wood is thus seen as an acceptable compromise between economical but less-stable flatsawn wood (which, especially in oak, will often display the distinct "cathedral window" grain) and the expensively-wasteful rift sawn wood, which has the straightest grain and thus the greatest stability.

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Wikipedia