Timber
Conversion means sawing of timber logs into different commercial sizes. A notable feature in conversion is to provide an adequate allowance for shrinkage that takes place during
seasoning of sawn or converted wood. The shrinkage of wood usually varies between 3.2 mm
to 6.4 mm, according to the type of wood and its time of cutting.
Seasoning of wood is the reduction of the moisture or sap content of it to the point where, under normal conditions of use, no further drying out will take place. The main objective of seasoning is to reduce the unwanted amount of moisture from the timber
Good timber is free from knots, insects attack, excessive moisture, discoloration, twisted fibers,
cup and ring shake, sound, bright and free from any discoloration. It is solid with annual rings
but not hallow in the center. Timber should be well seasoned for easily workable specific use.
It should possess straight fibers and high fire resistance. It should not split when nails are
driven in it. It should not clog with the saw teeth during the sawing operation. Timber should
be highly suitable for polishing and painting.
The factors influencing the selection of timber involve the quality of timber in terms of its durability, workability, weight, hardness, cohesiveness, elasticity, type of texture, type of grains, resistance to fire, resistance to various stresses, ability to retain shape, suitability for polishing and painting.
Timber is obtained from trees by cutting the main body of tree in the suitable sizes after the full growth of tree. The timber structure is consisting of annual rings, heartwood, sapwood, pith, cambium layer, bast, medullary rays and bark. Commercial timbers are commonly classified into hardwoods and softwoods. Hardwoods comprises of oak and beech that have a broad leaf. Whereas softwoods include pine and spruce which have narrow needle like leaf.
Conversion means sawing of timber logs into different commercial sizes. A notable feature in conversion is to provide an adequate allowance for shrinkage that takes place during
seasoning of sawn or converted wood. The shrinkage of wood usually varies between 3.2 mm
to 6.4 mm, according to the type of wood and its time of cutting.
Seasoning of wood is the reduction of the moisture or sap content of it to the point where, under normal conditions of use, no further drying out will take place. The main objective of seasoning is to reduce the unwanted amount of moisture from the timber
Good timber is free from knots, insects attack, excessive moisture, discoloration, twisted fibers,
cup and ring shake, sound, bright and free from any discoloration. It is solid with annual rings
but not hallow in the center. Timber should be well seasoned for easily workable specific use.
It should possess straight fibers and high fire resistance. It should not split when nails are
driven in it. It should not clog with the saw teeth during the sawing operation. Timber should
be highly suitable for polishing and painting.
The factors influencing the selection of timber involve the quality of timber in terms of its durability, workability, weight, hardness, cohesiveness, elasticity, type of texture, type of grains, resistance to fire, resistance to various stresses, ability to retain shape, suitability for polishing and painting.
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