Carpentry And Joinery (Paper 2) May/June 2015

Question 8

  1. (i)        Define the term timber conversion;
  2. (ii)      State two reasons for converting timber.
  1. State two reasons why a carpenter would prefer to use green timber to seasoned timber for formwork construction.
  2. (i)         make a pictorial sketch of a through mortise and tenon joint;
  3. (ii)         state one specific application of a through mortise and tenon joint in joinery.

Observation

Most candidates were able to:

  • define the term timber conversion;
  • state two reasons for converting timber;
  • state two reasons why a carpenter would prefer to use green timber to seasoned timber for formwork construction.

However, some candidates were unable to:

  • Make a correct sketching of a through mortise and tenon joint in pictorial view.
  • State one specific application of a through mortise and tenon joint in joinery.

The expected response to question 8 is as given below:
8.  a)        

(i)         Timber conversion – is the cutting of logs into commercial sizes.

 

(ii)         Two reasons of converting a timber:

  • to make timber available to suit various wood users.
  • for easy transportation of timber;
  • to get structural sound of pieces of timber;
  • To get physically attractive pieces of timber;
  • To remove some timber defects;
  • For quick drying of timber.

b)         Two reasons for using green timber for formwork:

  • Easier penetration of nails;
  • It reduces absorption of water from concrete.

 

(ii)         One specific application of through mortise and tenon joint.

  • between jamb and the head of door and window frames;
  • between stiles and rails of paneled doors;
  • between muntin and rail of paneled doors/windows;
  • in construction of kitchen cabinet.