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Wood / Timber

March 10, 2015

Wood is actually the term used when a tree is still alive. Timber is the term used for wood that has been cut. Timber can either plainsawn, quartersawn or riftsawn.

Plainsawing is the most common and least expensive method of sawing; most wood flooring is cut this way and it is the most economical way of cutting timber because it provides the widest boards and results in the least waste. Plainsawn lumber will tend to contain more variation within and among boards than quartersawn lumber, in which nearly all of the wood is vertical-grained. Also, since flat-grained wood is less dimensionally stable than vertical-grained, plainsawn lumber will tend to expand and contract more across the width of the boards than quartersawn lumber. Figure patterns resulting from the annual rings and some other types of figures are usually brought out more conspicuously by plainsawing. Also with plainsawing shakes and pitch pockets, when present, extend through fewer boards.

In quartersawing, lumber is produced by first quartering the log and then sawing perpendicular to the growth rings. Quartersawing produces relatively narrow boards, nearly all vertical-grained, and creates more waste, making quartersawn lumber more expensive than plainsawn. Quartersawn lumber twists and cups less, wears more evenly and it surface-checks and splits less during seasoning and in use. Raised grain does not appear as pronounced in timber cut like this but figuring due to pronounced rays, interlocked and wavy grain are brought out more conspicuously.

Riftsawing is similar to quartersawing, with many of the same advantages and limitations. It accentuates the vertical grain and minimizes the flake effect common in quartersawn oak. Riftsawing creates more waste than quartersawing, making it generally more expensive.

Wood is dimensionally stable when the moisture content is above the fiber saturation point (usually about 30 percent moisture content). Below that, wood changes dimension when it gains or loses moisture.

Type of Timber
Ash ranges in colour from white to light brown. Ash is a heavy hardwood with a prominent grain that resembles oak. It is widely used for structural frames and steam-bent furniture and is often less expensive than other hardwoods.

Beech is commonly used for chairs and woodturning. It is heavy and strong and ranges in colour from reddish brown to light brown. It is similar in appearance to maple. It is a relatively inexpensive wood often used for frames and furniture. Spalted beech is formed when the roots of fungi causes black lines on a living beech tree.

There are many species of Birch and the price of this wood depends on which country it originates from. It is a heavy and close-grained hardwood and ranges from cream, through to light brown or reddish brown. It can also be stained to resemble mahogany or walnut.

Cedar is red-brown softwood with light streaks. It is a knotty, lightweight and brittle wood with aromatic and moth repelling qualities, which is why drawers and wardrobes were typically made from this timber. Cedar ages to a soft gray when left unsealed outside.

Cherry is a light to red-brown wood and variations in color between pieces is particularly common in cherry woods, since manufacturers often produce chairs in one plant and tables in another. It is moderately hard, strong and close grained. It resists warping and checking well and is easy to carve and polish. Cherry wood naturally has small holes in it known as ‘gum pits’. Cherry wood is usually finished with a lacquer to give a shiny appearance. When looking at this finish under a light, you may see ‘swirl’ marks that look like scratches. This is a normal characteristic of the lacquer finish and is not a defect.

Cypress is a dense softwood that comes in pale yellow-white, dark brown or reddish-brown. Cypress has a natural preservative in the wood, which makes it longlasting and resistant to insects, making it idea for outdoor furniture. It also sands and finishes very well.

Elm is a very hardy reddish-brown hardwood. It is elastic, durable and does not split easily. Once properly treated it can be used underwater. Unfortunately elm has become rarer thanks to the onslaught of Dutch Elm Disease.

Hickory is one of the heaviest and hardest woods available and comes in white, tan or reddish brown. Pecan is a type of hickory wood and has a very close grain without much figure.

Mahogany is a strong highly-figured reddish brown hardwood. It is an excellent wood for carving and finishes beautifully. The mahogany that comes from the Caribbean is said to be the hardest, strongest and best quality. Mahogany from Africa is highly figured, but of lesser quality while mahogany from the Philippines has a similar color to Caribbean mahogany, but is not as strong, durable or beautiful when finished.

Maple is so hard and resistant to shocks that it is often used for bowling alley floors. Its colour ranges from light tan or cream, to a light reddish-brown and its diffuse, evenly sized pores give this hardwood a fine texture and even grain. Maple that has a curly grain is often used for violin backs and maple with burls, leaf figure, or bird’s-eye figures are used extensively in objet d’Art and fine furniture. Maple can be stained to simulate cherry wood, which it resembles.

A very popular hardwood oak is a heavy, strong wood that comes in two basic varieties; white and red. Sometimes the red variety is also called black oak, in reference to the black bark on the living tree. Prominent rings and large pores give oak a course texture and prominent grain. Oak also has conspicuous vascular rays which can be seen as “flakes” in quarter sawed oak lumber. ‘Brown’ Oak is actually white oak that has turned brown due to a fungal infection.

Pine is a white or pale yellow softwood grown mostly in the Northern Hemisphere. It is lightweight, straight-grained timber without a lot of decorative figuring although the knots in the time are often used for decorative effect. Pine resists shrinking and swelling and is an ideal candidate for decorative treatments such as distressing or painting.

Rattan is a softwood derived from climbing Asian palms whose stems grow to great lengths

As the name suggest redwood is red and the best quality redwood comes from the tree’s heartwood which is resistant to sunlight, moisture and insects. Burls in this softwood are rare and valuable.

Teak is indigenous to Southeast Asia, but similar wood species also grow in Africa. Teak is an extremely heavy, strong and durable hardwood and ranges in colour from yellow to dark brown. Often strongly figured, teak may show straight grain, mottled or fiddle-back figures. It carves well, but because of its high value, is often used as a veneer.

Walnut varies from light to dark chocolate brown. It is strong, hard and durable, without being excessively heavy. It has excellent woodworking qualities, and takes finishes well. Large burls are common in walnut wood and walnut solids and veneers show a wide range of figures, including strips, burls, mottles, crotches, curls and butts. European walnut is lighter in color and slightly finer in texture than American black walnut, but they tend to perform similarly.

Classes of timber for joinery
Class CSH Clear softwood and hardwood, i.e. free from knots or other surface defects
Class 1 Suitable for small components, i.e. glazing bars and beads
Class 2 Suitable for general purpose joinery, i.e. window frames
Class 3 As class 2 but with more flexibility in terms of imperfections

 

Softwood – Standard Sawn Sizes (mm)
Thickness 25 38 50 75 100 125 150 175 200 225 250 300
12 x x x x x x
16 x x x x x
19 x x x x x x x
22 x x x x
25 x x x x x x x x x x x x
32 x x x x x x x x x
36 x x x x
38 x x x x x x x x x
44 x x x x x x x x x
47 x x x x x x x x x
50 x x x x x x x x x x
63 x x x x x x
75 x x x x x x x x x

 

Hardwood – Standard Sawn Sizes (mm)
Thickness 50 63 75 100 125 150 175 200 225 250 300
19 x x x x x
25 x x x x x x x x x x x
32 x x x x x x x x x
38 x x x x x x x x x
50 x x x x x x x x
63 x x x x x x
75 x x x x x x
100 x x x x x x

Glossary
Wood is defined as live material, i.e. still growing whereas timber is wood that has been felled (cut down).

Wood Figure is a term used to refer to the natural variations in a wood’s grain.

Small clusters of knots are called pips or burrs. Oak, elm and sycamore often have this feature.

Heartwood is the older, harder central portion of a tree. It usually contains deposits of various materials that frequently give it a darker color than sapwood. It is denser, less permeable and more durable than the surrounding sapwood.

Veneer is an extremely thin sheet of timber. Veneer comes in various grades with grades AA and A being suitable for furniture. Veneers need some sort of edging to prevent them from chipping. Veneer

Case hardened is used to describe timber that has been improperly dried. If dried too quickly, wood shrinks heavily on the surface compressing it’s still damp interior. This can cause the wood to warp considerably and can be potentially dangerously when the stress is relieved by sawing.

Timber can be hardened by steaming, fuming and heat treatment. The hardness of timber is measured using the Brinell Scale.

See our page on timber flooring

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One comment

  1. […] our page on the different types of wood […]



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