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
(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)