Flat sawing,flitch sawing orplain sawing is a woodworking process that producesflat-cut orplain-cut boards oflumber.[1]
After an initial cut through the diameter of a log, parallel cuts produceflitches: strips of lumber with consistent thickness.[2] Two cuts on each flitch trim the bark from the sides, and reduces it to a standard board width with squared edges. Two more cuts at each end set the length.
Lumber can be quickly flat-cut with a side-by-side set ofmechanical saws.[3] A slower but sturdier method involves passing the log back and forth over a single saw.
To reduce buckling that may occur along the middle of flat-cut boards, the initial cut may be offset from the diameter, and resulting sections cut further before cutting the flitches.
Flat-sawn wood often exhibits "flat-" or "slashgrain", where the angle between the visiblegrowth rings and the width of the board is 45° or less.[4] This makes the wood vulnerable todeformation as it dries, or if later exposed to moisture. Flat-sawn wood is less stable thanquarter sawn orrift sawn wood, but can be produced more quickly and at lower cost.[5]
The face of the board may show curved grain, sometimes with intricate patterns.
