Carpentry And Joinery (Paper 2) WASSCE (SC), 2017

Question 7

 

(a)        draw the cross section of a tree and label four of its parts
(b)        state main reason for constructing each of the following joints:
 (i)         wedge mortise and tenon joints;
 (ii)        scarf joints;
(iii)      tongue and groove joint;
(iv) bare face mortise and tenon joint.

(c)        Sketch to illustrate the dovetail method of nailing.

Observation

Few candidates were able to:
   -           draw the cross section of a tree and label four of its parts;
  -           state main reason for constructing each of the following joints:

(i)         wedge mortise and tenon joints;
(ii)        scarf joints;
(iii)      tongue and groove joint;

  • bare face mortise and tenon joint.  
  •  

However, most of them failed to

  • sketch and illustrate the dovetail method of nailing

The expected response to question 7 is as given below:

7.         (a)        Cross section of a Tree

diag

(b)        Reason for constructing the following joints:

                        (i)         Wedged mortise and tennon    -       additional strength;
(ii)        Scarf joint                                 -      produce longer members;
(iii)       Toungue and groove                -       produce wider piece from narrow
pieces;
(iv)       Bareface mortise and tennon   -       where the leg/stile is much thicker
than the rail.

(c)

diag2