Question 1
(1) The figure below shows three cylindrical pipes (J, K, L) of same diameter 50
and of negligible thickness joined together.
Draw full size, the:
(a) given view;
(b) development of the pipe K using the shorter side as the seam.
Observation
This question involves the surface development of a part of a bent cylinder.
Candidates are to copy the given view, draw a partial plan and divide it into twelve equal parts. The numbered parts are then transferred to the elevation to the two joints of the pipe to be developed.
Many of the candidates failed to draw the partial plan and transfer the numbered parts to the elevation.
Candidates were expected to:
(i) draw the given views full size;
(ii) draw the plan and divide it into twelve equal parts;
(iii) project the numbered points onto the elevation to the two joints of
pipe K;
(iv) project the numbered points on K at right angles to the seam MN;
(v) lay out the circumference 1, 11 and divide it into twelve equal parts;
(vi) draw the perpendicular lines through the divisional points on the circumference;
(vii) locate the corresponding points for the development;
(viii) draw a smooth curve through the points to obtain the development;
(ix) use MN as the seam;
(x) draw neatly.
The solution is shown below: