2017/2018 Technical Drawing obj and essay theory Questions and answers Now posted for free
By Mr Method  On March 22, 2017 (9 months ago)
WAEC T/D ANSWER
ANSWER SECTION A (PART 1)
(a) Draw the true shape of the laminae.
(b) Measure and state the:
(i) angle of inclination to the horizontal plane;
(ii) true length of AC.
(c) Indicate on the drawing, the:
(i) auxiliary elevation;
(ii) auxiliary plan.
ANSWER


Candidates were expected to:
(a) (i) COPY THE GIVEN VIEW:
(1) draw the front elevation;
(2) draw the plan;
(3) draw the X – Y axis.
FIRST AUXILIARY ELEVATION:
(ii) (1) draw the horizontal line, A1D1 in the front elevation;
(2) project from D1 to D in the plan;
(3) join AD and extend it beyond the X – Y axis;
(4) draw parallel lines from B and C respectively to the line AD extended;
(5) draw X1Y1 axis perpendicular to AD extended;
(6) locate B2, A2D2 and C2 using X – Y as datum with the corresponding dimensions from the elevation on X1 Y1 for the first auxiliary elevation;
(7) draw the first auxiliary elevation.
(iii) TRUE SHAPE (SECOND AUXILIARY PLAN)

draw X2Y2 axis parallel to B2 C2 ;

locate A3, B3 and C3 use X 1 Y1 as the datum with the corresponding dimensions from the plan on X2Y2;

join the points A3, B3 and C3 to obtain the true shape.
(b) Measure, indicate and state the:
(i) angle of inclination to the H.P = 590 ± 10 ;
(ii) true length of AC = 66 ± 1;
(c) Indicate:
(i) auxiliary elevation;
The solution is shown below:
ALTERNATIVE METHOD
TRUE SHAPE OF TRIANGULAR LAMINAE
Candidates were expected:

(i) COPY THE GIVEN VIEWS:

draw the front elevation;

draw the plan;

draw the X – Y axis.
(ii) TRUE SHAPE:

draw to obtain the true length AB;

draw to obtain the true length of AC;

using the true lengths to obtain the true shape.

(i) Measure and state:

angle of inclination to the horizontal plane (HP) 59 ± 1;

true length of AC = 66 ± 1.
(c ) Indicate:

auxiliary elevation;

auxiliary plan (true shape).The solution is shown below:
ANSWER NO 3
(a) INTERNAL TANGENT TO TWO UNEQUAL CIRCLES:
(i) draw two vertical centre lines at A and 100 apart;
(ii) draw one horizontal centre line;
 draw two unequal circles Ø30 and Ø58 at A and B respectively;
 draw another circle Ø88 (Ø58 + Ø30) at centre B;
 bisect AB and draw semicircle on AB;
 join BD to intersect circle Ø58 to locate point T;
 draw a line at A parallel to BD to the smaller circle Ø30 to locate point P;
 join PT to obtain the internal tangent;
 measure and state the length of tangent PT = 91 ± 1.
The solution is shown below:
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