Question 1
(1) (a) State three metalwork operations for which goggle must be worn.
(b) State one merit of each of the following operations:
i. dot punching of a marked-out line;
ii. centre punching;
iii. chalking the surface of the steel rule.
(c) (i) What is an alloy?
(ii) State one effect each of alloying metals with:
I. chromium;
II. tungsten.
Observation
This question was well attempted by the candidates. The areas of difficulty were in
1(bi), (biii) and (cii) (II). The responses expected are given below.
1 (b)
(i) Dot Punching of a markedout-line.
It highlights scribed lines and serves as a guide when sawing, filing, chiseling, machining, scraping, shearing, etc.
It does not serve as a pilot hole as erroneously believed by the candidates.
(iii) The correct answer to it is that it makes reading of the measurement on the steel rule very clear.
Chalking the surface of the steel rule does not serve as anti-rust to the steel rule.
(c) (ii) The effect of alloying metals with Tungsten gives wear resistance at high temperature to the metal.