Flat sawing

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Lumber produced by flat sawing from a log. Plank A has been cut from the middle, and is as wide as the original log. Plank B has been cut closer to the side, and shows slash grain.

Flat sawing, flitch sawing or plain sawing is a woodworking process that produces flat cut or plain cut boards of lumber.[1]


After an initial cut through the diameter of a log, parallel cuts produce flitches—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 of mechanical 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 "slash grain", where the angle between the visible growth rings and the width of the board is 45° or less.[4] This makes the wood vulnerable to deformation as it dries, or if later exposed to moisture. Flat-sawn wood is less stable than quarter sawn or rift 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.


  1. ^ Nagaratnam Sivakugan; Carthigesu T. Gnanendran; Rabin Tuladhar; M. Bobby Kannan (2016). Civil Engineering Materials. Cengage Learning. p. 382. ISBN 9781337514606.
  2. ^ Rick Peters (2006). Band Saw Fundamentals. Hearst Books. p. 77. ISBN 978-1-58816-522-0.
  3. ^ How A Wind Powered Sawmill Works (Video). YouTube. May 10, 2016.
  4. ^ Stanley R. (Rob) Gustafson, ed. (2014). "Glossary". Architectural Woodwork Standards (PDF). Architectural Woodwork Institute (AWI), Architectural Woodwork Manufacturers Association of Canada (AWMAC), and Woodwork Institute (WI).
  5. ^ What is the difference between Quarter Sawn, Rift Sawn and Plain Sawn Lumber? - Hardware Distributor's Association