Question 1
(a) Candidates were asked to illustrate the following timber defects: loose knot and thicknesser.
(b)State two possible results of planing a timber with a loose knot on the thicknesser.
(c)State the main function of each of the following parts of a tree: crown, trunk and roots.
Observation
(1)
(ii)
(b) - loose knots fall off and bind in between the rollers of the machine or fly and cause injury;
- result in kick-back;
- are harder than the surrounding wood tissues this dull or chip the cutter;
- deface the finished work piece.
(c)(i) Crown
produces nutrients to feed the tree / support the spread of branches /flowers /fruits / and seeds
(ii) Trunk
supports (carries) the crown / used to produce timber
(iii) Roots anchor the tree and absorb moisture and minerals from the soil / it prevents soil erosion.
Some of the candidates did not understand the difference between cup and cup shakes in timber defects. Cup defects is an artificial defect.