Drawing and Design Paper 1 Questions and Answers - KCSE 2021 Past Papers

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SECTION A (50 Marks)

Answer all the questions in this section on the A4 sheet provided.

1. State four ways of caring for the drawing instruments. (2 marks)
2. Name two types of lines used in technical drawing and state where each is applied. (2 marks)
Explain the use of each of the following in drawing:
1. Sketches
2. Assembly drawings
3. Exploded views
4. Working drawings (4 marks)
1. State three factors to consider when choosing materials for engineering works. (3 marks)
2. Explain the meaning of the term "alloy" as applied in materials and give two examples. (2 marks)
1. State two reasons for using symbols and abbreviations in drawing. (2 marks)
2. Draw the symbols representing each of the following welded joints:
  1. Fillet
  2. Double-Vee butt (2 marks)
1. Use sketches to show four ways of dimensioning arcs in drawing. (2 marks)
2. Use a cuboid to illustrate the difference between oblique projection and one point perspective projection in drawing. (2 marks)
Figure 1 shows a shaped block drawn in isometric projection.

Sketch in good proportion the three orthographic views of the block in third angle projection. (6 marks)
1. Explain the meaning of each of the following scales in relation to the size of the drawing and the actual object: (2 marks)
  1. 1:50
  2. 50:1
2. Construct a parallelogram whose two opposite sides are 65 and 40 given that the angle between two adjacent sides is 60°.
  (5 marks)
Figure 2 shows the front elevation of a truncated hexagonal pyramid. Draw the given view and (5 marks) complete plan in first angle projection. (5 marks)
1. Write each of the following abbreviations in full as used in computer applications:
  1. CAM
  2. CAD (2 marks)
2. Figure 3 shows views of the part of a machine component drawn in first angle projection
  
  Assemble the parts and sketch the component in oblique projection with A as the front face. (6 marks)
Explain the importance of each of the following in the design process:
1. Research
2. Evaluation (3 marks)

SECTION B (20 Marks)

This question is compulsory.

It should be answered on the A3 paper provided.

Figure 4 shows parts of a clamp drawn in first angle projection.

Assemble the parts and draw Full Size the following in third angle projection:
1. Sectional front elevation along the cutting plane P-P
2. Plan
  Unspecified dimensions are left to the candidates discretion. (20 marks)

SECTION C (30 Marks)

Answer any two questions from this section on the A3 paper provided.

Figure 5 shows three orthographic views of a casting drawn in first angle projection.

Draw the casting in isometric projection taking the corner X as the lowest point (15 marks)
In the mechanism shown in Figure 6, the crank EF rotates about centre E ehilr GH oscillates about G. Plot the locus of the point P for one complete revolution of EF. (15 marks)
Figure 7 shows two intersecting squares tubes A nd B drwn in 1^st angle projecion
1. Copy the figure and complete each of the following:
  1. Front elevation
  2. Plan
2. Draw the development of tube B. (15 marks)

MARKING SCHEME

SECTION A

1.	Ways of caring for drawing instruments: Avoid dropping so that they do not break or deform thus ensuring durability. Do not keep near heat or open sun to avoid bending/sagging. Always store in their racks to avoid them collecting dust. Use instruments for the correct/appropriate use (Avoid misusing the instruments) Any 2 x 1 Types of lines used in technical drawing: Bold/Dark continuous lines-used to show visible outlines. Thin short dashes-used to show hidden details. Thin long chains-used as centre lines or lines of symmetry. Thin continuous lines --used as construction lines, projection lines, layout of work. Medium continuous lines - For hatching/Dimensions Naming, any 2 x ½ =1 Uses, any 2 x ½ = 1 Total 2	(2marks) (2marks)
2	Sketches are used to show rough layout of drawings or represent ideas which have been conceived. Assembly drawings-show elevations, sections and plans of various parts of a component fitted together. Exploded views-show separated parts arranged in the order in which they fit to form a complete item. Working drawings -Detailed drawings used in the production process or on construction sites (Any 4 x 1)	(4 marks)
3	Factors to consider when choosing materials for engineering works: Use of the item to be fabricated/manufactured. Availability of the materials. Durability of the materials. Cost of the materials. Weather conditions (internal and external use). Ease in the use of the material (workability). (Any 3 x 1) Alloy is a metal made from two or more metals. Examples of alloys - Bronze, Brass, Solder Meaning = 1 2 examples @ 2 x ½ = 1 Total 2 marks Accept any other alternative	(3 marks) (2 marks)
4	Reasons for using symbols and abbreviations: To avoid use of too many words. To ensure uniformity in interpretation of drawings (clarity). To allow for understanding of ideas between diverse communities and nations. To make the drawing universally acceptable To save on space thus saves time (Any 2 x 1) 2 x 1	(2 marks) (2 marks)
5	Ways of dimensioning arcs: 4 x ½ Correct length of sides 4 x ½ = 2 marks Construction of 60% = 2 marks Complete drawing = 1 mark Total = 5 marks	(2 marks) (5 marks)
8	Construction of plan with correct A/C - 1mk Projection from plan to get correct F.E - 1mk Projection of the truncated face to the plan - 1mk Completion of plan - 1 mk Correct hatching - 1mk	(5 marks)
9	CAM - Computer Aided Manufacturing CAD - Computer Aided Drawing/Design 2 x 1 9 faces @ ½ = 4½ Assembly = ½ Oblique = ½ Front face = ½ Total = 6 marks	(2 marks) (6 marks)
10	The importance of: Research To collect or source for information relevant to the design. Feasibility study Easy to market Evaluation To help the designer know whether the project objectives have been met. Whether the design brief has been satisfied. 2 x 1½ = ,3 marks	(3 marks)
SECTION B
11	PLAN Assembly of the 4 parts = 4mks Threads = 1mk 10 Hole = 1mk 6mks F. ELEV. Assembly of the 4 parts = 4mks Hatching = 2mks Screw threads = 1mk 10 Hole = 1mk 8mks GENERAL Correct angle of projection = 2mks C/Line = 2mks H/Details = 1mk Line work = 1mk 6mks	(20marks)
SECTION C
12	11 Faces @ 1 = 11mks Quality of curves - 4 x ½ = 2mks Isometric = ½ Line work = ½ Lowest point = 1mk 15mks	(15marks)
13	CIRCLES Centres E $ G = 2 mks Radius EF = 1 mk Radius GH = 1mk Locating point P = 1mk Division of circle EF = 3 mks Plotting locus, point P = 3mks Smooth curve = 3mks Neatness = 1mk TOTAL 15 mrks	(15marks)
14	M/S Correct figure drawn = 2mks F.E Four Faces @ 1 = 4mks Plotting the line of intersection = 1mk PLAN Four faces @ 1 = 4mks DEV Development = 1mk Shape of Hole = 2 mks Folding Lines = 1mk Total 15mks	(15marks)