Sawmill Terms For Beginner Sawyers

If you are starting out in the sawmill industry, you are probably finding out just how much there is to learn. One thing you will quickly realize is that this industry uses some very specific terms that you may have never heard before. To help you out, here are some common sawmill terms to add to your vocabulary.

Board feet – The volume of wood that gets purchased from the sawmill. Board feet is calculated by using a specific formula: LENGTH x WIDTH x THICKNESS / 144.

Boxed heart timber – When the four surfaces of sawn timber encloses the heart throughout its entire length. Free of heart timber, on the other hand, excludes the heart.

Cant – A piece of wood that is sawn on at least three sides and is usually over 2 inches thick. It also refers to a partially sawn log that has at least one flat side.

Cathedral grain – Produced from flat cut veneers, this kind of grain pattern is characterized by a loop in the center with straighter grain along the edges, giving it the appearance of a cathedral.

Charge – A stack of lumber that has been dried and processed in a kiln.

Dry kiln – A closed chamber in which wood is placed in order to reduce its moisture content. Both the temperature and humidity levels must be controlled and well monitored.

Equilibrium Moisture Content (EMC) – The point at which wood is neither gains or loses moisture, which means it is no longer affected by the moisture in the air so that it no longer expands or shrinks. The EMC depends upon the relative humidity and air temperature of the wood’s environment.

Flitch – An unedged piece of lumber in which the edges are rounded. It also refers to a thick piece of wood that is cut from a tree trunk and usually requires further processing.

Grading – The standardized way of judging the quality of lumber. Softwood (which comes from gymnosperm trees) is graded according to its application, appearance, and load-bearing capacity. Hardwood (which comes from angiosperm trees) is graded according to appearance and size.

Grain – The longitudinal arrangement of fibers on a piece of wood. The six general types of grain include:

• Straight

• Irregular

• Diagonal

• Spiral

• Interlocked

• Wavy

Green – Recently cut wood that has not had a chance to dry.

Heartwood – The central part of a tree trunk that contains old and matured wood and is usually a different color from the outer layers. Another term for heartwood is duramen.

Head rig – The center part of the sawmill where the saw converts the log into lumber. The conveyer on which the log is placed can either be a stationary carriage or a mobile one. On a stationery carriage, the head rig moves its blade through the log. Mobile conveyors have fixed head rigs.

Kerf – Refers to the width of the cut that a saw blade makes. It can also refer to the thickness of a saw blade.

Log – A tree that has been cut into a length of 8 feet. This length is considered easy to haul out of a forest. Sawmills usually require a log to be at least four inches longer than the exact length as to account for any cutting mistakes.

Lumber – Wood that has been processed into beams or planks and is sometimes referred to as timber. There are generally two kinds of lumber, which include rough-sawn or finished. Rough-sawn lumber is wood that gets cut to a basic size, but its edges and sides are not smooth. Finished lumber on the other hand is supplied in standard sizes and all four sides have been processed.

Plain sawn – Also known as flat sawn, this is the most common type of cut an also the most inexpensive way to turn logs into lumber. The first cut gets made on a tangent to the circumference of the log, which makes the annular rings 30 degrees or less to the face of the board. Other types of cuts include:

·         Quarter Sawn – The lumber is cut into four quarters at a radial angle, which makes the annular rings 60 to 90 degrees to the face of the board.

·         Rift Sawn – The lumber is cut at an angle, which makes the annular rings between 30 to 60 degrees but look best at 45 degrees to the face of the board.

·         Live sawn – The lumber is cut straight off the log in one direction without turning it, which makes angles anywhere between 0 to 90 degrees.

Planing – The lumber receives its final size and appearance before it’s bundled and shipped. This is done by flattening and smoothening a rough piece of lumber. Thickness can also be reduced during the planning process. Planed lumber then gets marked with a finished grade stamp.

Portable sawmill – A simple version of a sawmill on which a motorized saw is used to cut a piece of wood that lies on a steel bed. The operator must push the log through, which is then cut horizontally.

Ray cells – Also called parenchyma, these living tissues extend radially in wood and hold annual growth rings together.

Ray fleck – The side view or appearance of ray cells in quarter sawn wood.

Resawing – A secondary process in which multiple bandsaw blades reduce the size of large cants into smaller ones.

Sawyer – Any person that saws wood for an occupation or one who operates a sawmill.

Teeth – The sharp points of a saw that are set a certain distance apart, which is referred to as the pitch. The gauge refers to the width of the teeth. There are three common types of saw blade teeth, which includes:

• ATB – Alternate Top Bevel

• FTG – Flat Top Grind

• TCG – Triple Chip Grind

Veneer – Thin slices of natural wood that is obtained by peeling the trunk of a tree or by slicing flitches.