Basic Technology JSS3 First Term

WEEK – THREE

WOOD DEFECTS

PERFORMANCE OBJECTIVE

By the end of the lesson, the students should be able to learn:

• Wood defects
• Veneer
• Manufactured boards

CONTENT

WOOD DEFECTS:

A defect in timber is any feature in timber that reduces the quality and market value of timber. Defects in timber can be grouped into two types

1. The natural defects: these are the defects that occur during the growth of the tree. Examples include knots, shakes, upset grains and cross grains.

1. KNOT: These occur at the point where branches grow from the trunkof trees. When the knot rot away and fall out of position it leaves what is known as knot-hole
2. SHAKES: These.... View More