However, defect caused by fungal attack and decay in wood is known as Unsoundness. (A) NATURAL DEFECTS (Knots, Shakes, Cross grain, Compression)(B) OTHER THAN NATURAL DEFECTS: These defects include the(1) Defect caused during treatment of felled timber (Seasoning defects and Conversion defects); the seasoning defects include:- (Warping, Split, Shake, Collapse, Case hardening) and the defects due to conversion includes:-( Box heart, Machine burnt, Machine notches, Miscut, Imperfect grain)(2) Defect resulting from activity of external agent (animals, insects and fungus)(A) NATURAL DEFECTS:1. Solution for checks and shakes: These cracks occur at the ends of boards, so you may simply cut off the bad areas. But don’t be too hasty. Good narrow pieces often exist on either side of a check. If the exposed wood is sound, the knot is sound; if rotten, it is unsound.
In presence of knots processing a timber is not so easy and due to this timber also becomes weaker in section. Growth-related defects are imperfections in the wood of living trees, which arises from tree growth, or irregularities of growth. A knot is a branch base that is embedded in the wood of a tree trunk or of a larger limb or branch; such branch bases gradually included in the wood of the larger member through addition year by year of successive increments of woody tissue. Presentation try to cover as many defects as possible in an interactive manner. AS CONTINUITY OF WOOD FIBRES ARE BROKEN BY KNOTS,THEY FORM A SOURCE OF WEAKNESS.
A ‘defect’ is generally an imperfection, which either weakens the wood greatly or makes the wood unsuitable to work with for the purpose it is to be used. ‘Knots’ are probably the most common defect in timber. Sam Rogers’ Common Wood & Lumber Defects. A knot fixed by growth or position in the wood structure so that it firmly retains its place in the surrounding wood. One of the biggest challenges of working with timber is learning to work within the constraints of a timber’s. The following are a list of the most common wood defects. Localised slope of grain can be caused by knots. Slope of grain can also be caused by a slight bend in the tree, which means that when a straight board is cut out of it, there is a bend in the grain.
Bansal’s Wiki: Defects In Wood
A knot is a particular type of imperfection in a piece of wood; it will affect the technical properties of the wood, usually reducing the local strength and increasing the tendency for splitting along the wood grain, but may be exploited for visual effect. They are defects which weaken timber and lower its value for structural purposes where strength is an important consideration. Official Full-Text Publication: Wood defect classification based on image analysis and support vector machines. A tree-structure support vector machine (SVM) is proposed to classify four types of wood knots by using images captured from lumber boards.