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Originally veneer was saw cut by hand. This was a laborious process and the material was relatively thick and in quite small pieces.
When veneer began to be saw cut commercially the machine used was a flat travelling bed passing under a saw consisting of a wooden disk perhaps a meter in diameter with segments of very thin saw fixed to its periphery. This produced a thinner veneer but still 1.5 to 4 millimetres thick. It was a very wasteful method as up to half the material was lost as saw dust. The other disadvantage of sawn veneer is that as so much material is lost in the saw cut the matches you can get from a bundle of material is limited.
Modern veneer is almost exclusively knife cut. That is it is sliced or peeled from the solid wood in one way or another. The vast majority of veneer is used in the manufacture of Plywood and other man made boards. Constructional veneer varies in thickness from .25 mm to maybe 5 or even 6mm thick. More normally it is between perhaps 1 to 4 mm thick.
Most constructional veneer is peeled. That is a log of wood generally after having been boiled to soften the fibres is set up in a machine resembling a big late and rotated against a blade as long as the log. This effect can often be seen very clearly in European Birch plywood. Birch is a small tree more suitable for veneer than use in the solid . If you examine a sheet of birch ply you will often see features of the grain such as knots swirls and patches repeated at regular intervals across the board.
Veneer produced by peeling is not generally considered suitable for decorative veneering. In order to enhance the beauty of fine veneer it is cut from the log in various ways depending on the effect required. The basic cut is flat. the log or the flitch is dogged to the bed of the machine and a long blade, always cutting across the grain, travels on a slide, usually horizontally. Each leaf of veneer is removed like a huge shaving from a plane. The blade is lowered a set amount between each cut.
In plain material, veneer cut radially from the tree will show plain straight grain. This is somewhat enhanced by the medullary ray figure or “silvergrain” in oak and a few other species. This corresponds to quarter sawing in solid wood and so gives the effect of the most expensive cut.
Veneer cut tangentially to the annual rings referred to as crown cut (equivalent to through and through or “slash” sawing) shows an elliptical or parabolic grain pattern in the middle of the leaves with the lines getting closer together and straighter towards the edges. This effect is accentuated if the material is “semi rotary” cut.
When it is removed from the machine each leaf is set in a rack to dry. When they are dry the leaves are placed back together in the relationship they had in the log. The leaves may be individually numbered but if they are not the bundles will be. Bundles of veneer are usually packed in 24s or 32s. Traditionally veneer was cut at 32 to the inch , thus a bundle is an inch thick. We now expect veneer, unless specified otherwise, to be about 0.7 to 0.8 mm thick. It is usual to buy veneer at least by the bundle, but some merchants will sell individual leaves. When buying more than one bundle from the same log it is usual to make sure that they are consecutive.
Veneering has got a bad name as being somehow inferior to “real wood”.
The process of veneering is simply one of overlaying a usually unattractive or plain substrate with a thin layer of a decorative or otherwise more desirable material.
The very survival of some historical furniture may have depended on its veneer, and many walnut period pieces in existance today were made of quite inferior material and covered with walnut veneer. Not a cheap material, as the amount of labour involved in cutting the veneer by hand was enormous.
In these days of ecological awareness, it is surely a good thing to use the beauty of fine rare timbers over a material made from more easily renewable sources .
The great advantage of veneer over solid wood is the ability it gives one to enhance the timbers beauty by matching and repeating its natural patterns.
Veneer allows us to use the beauty of defects which would render the timber unusable in the solid form. Burrs and curls (burls and feathers) have virtually no practical use except as veneer.
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