The Technique of FURNITURE MAKING

Texture

Texture is concerned with the relative size and arrangement of the cells. Thus a wood with large open pores usually referred to as coarse grain is more correctly coarse textured; with small pores set close together which can be brought to a good finish as fine or close textured; with uniform pores showing little difference between springwood and summerwood even textured, with the reverse for uneven textured. Oak, ash and elm are coarse textured (coarse grained) woods, because there is an alternation of large open pores of the springwood with the densely packed fibres of the summerwood.

Figure

Structural characteristics, medullary rays, pro­nounced or irregular growth rings, variations in colour or texture, knots and abnormalities all produce the ornamental markings or 'figure' on the surface of the wood, and are of great import­ance to the furniture-maker. All these are innate, i. e. natural characteristics, and can be further developed or exaggerated by the methods of sawing adopted. For example, radial cuts in true quartered oak and chestnut follow the path of the medullary rays, and show the typical 'flash' or 'silver grain' to best advantage. These rays are also visible in quarter-cut beech, while sycamore will some­times produce a magnificent flame figure, and plane a rich lacy pattern (lacewood). Again, quarter sawing of some timbers produces very straight regular grain patterns, instead of the usual contour markings of flat sawn timber where the saw cuts through the annual growth rings. If there are concentric bands of colour encircling the tree, as in Rio rosewood, Macassar ebony and other exotics, then quartering will produce boldly marked vertical stripings, and plain sawn wood large irregular blazes of predominant colour. Woods with a marked contrast between springwood and summerwood often show the annual growth rings very conspicuously if plain cut, and even more so if rotary cut into veneers, of which typical examples are the resinous softwoods, Douglas fir (Columbian pine), yellow pine, pitch-pine, etc., and the ring-porous hard­woods, ash, oak, elm, etc. Bold demarcations between sap and heartwood yield the prized laburnum oysters, the strong pattern of royal walnut, and the delicate feathering of some walnut crotches.

Some of the most beautiful figurations are obtained from irregular grain structure. Wavy and curly grain can yield quilted and swirl figure, and the very beautiful dapple and mottle in which alternate light and dark bands cross the grain direction instead of running with it. This transverse movement can occur in many woods, and has always been highly prized in sycamore for the backs of violins. A variation of the stripy figure is 'roe', in which local irregularities break up the stripe, while similar irregularities or dimples in the cambium layer produce the blister grain of Douglas fir, and smaller inward- growing dimples one type of burr or burl as in burr maple. Sometimes the crotch or fork of the

tree produces the self-descriptive and highly prized fan, feather, swirl and curl figuring; while the buttress or root base of some trees, notably walnuts, the very bold-patterned stump figure.

Some abnormalities produce striking figure, notably burr formations caused either by fungal irritation of the cambium layer, severe pollarding or lopping, or in the case of elm, natural growth irregularities. Burrs or burls can also be caused by large numbers of small twigs which fail to develop, and yield the familiar bird's eye in maple, etc. Examples of some of these figure markings are shown in 16, but it would be impossible to include all the known varieties, for practically every species of tree is capable of yielding outstanding effects in grain. texture and colour, and there are many recorded instances of exceptional logs suitable for veneering bringing very large sums of money.