education.gov.za NSC Examination Mechanical Technology Question Paper : Department of Basic

Organisation : Department of Basic Education
Exam : National Senior Certificate Examinations
Document Type : NSC Sample Question Paper
Subject : Mechanical Technology
Category : Grade 12
Year : 2017
Website : https://www.education.gov.za/2017FebMarchNSCExamPapers.aspx
Download Sample Question Paper :
Paper 1 : https://www.southafricain.com/uploads/10932-Mechanical.pdf
Memo 1 :  https://www.southafricain.com/uploads/10932-Memo.pdf

Education NSC Mechanical Technology Question Paper

Marks : 200
Time : 3 hours
** This question paper consists of 15 pages and a 4-page formula sheet.

Related : Department of Basic NSC Examination Electrical Technology Question Paper 2017 : www.southafricain.com/10896.html

Instructions & Information

1. This question paper consists of TEN questions.
2. Write your centre number and examination number in the spaces provided on the ANSWER BOOK.

3. Read ALL the questions carefully.
4. Answer ALL the questions.
5. Number the answers correctly according to the numbering system used in this question paper.

6. Start EACH question on a NEW page.
7. Show ALL calculations and units. Round off ALL answers to TWO decimal places.
8. Candidates may use non-programmable, scientific calculators and drawing instruments.

9. Take the value of gravitational force as 10 m/s-2.
10. All dimensions are in millimetres, unless stated otherwise in the question.
11. A formula sheet for your use is attached to this question paper.
12. Write neatly and legibly.

Sample Questions

QUESTION 1: MULTIPLE-CHOICE QUESTIONS
Various options are provided as possible answers to the following questions. Write down the question number (1.1–1.20), choose the answer and make a cross (X) over the letter (A–D) of your choice in the ANSWER BOOK.
1.1
Which ONE of the following safety measures applies to a power saw?
A Make sure that the cutting speed is set at the highest setting for the best performance.
B Long pieces of material must be supported at the ends.
C Make sure the blade is properly oiled.
D Tighten the blade while the machine is in motion.(1)

1.2 Which ONE of the following safety measures applies to a tensile tester?
A Apply excessive pressure on the tester.
B Use a hammer to remove a test piece.
C Lower the fluid level of the tester.
D Wear eye protection. (1)

1.3 A Rockwell tester is used to test the … of a material.
A tension
B elasticity
C hardness
D brittleness (1)

1.4 Which ONE of the following is a reason for a high carbon-monoxide reading on an internal combustion engine?
A High compression
B Warm valves
C A clogged air filter
D Piston rings set too tight (1)

1.5 An austenite structure is …
A strong and brittle.
B soft and malleable.
C hard and malleable.
D soft and brittle.

1.6
The second arrest temperature (AC2) for carbon steel is …
A 1 000 °C.
B 120 °C.
C 320 °C.
D 800 °C.(1)

1.7 The minimum diameter of a screw thread is measured at the … of the screw thread.
A root
B axis
C crest
D lead (1)

1.8 What is the gear ratio of a Cincinnati dividing head used on a milling machine?
A 60 : 1
B 40 : 1
C 50 : 1
D 30 : 1 (1)

1.9 Which ONE of the following is a common cause of incomplete penetration into a welded joint?
A The welding current was too low
B Slag not removed from the first weld before the second weld was run
C Faulty restart by not restarting at the top of the previous weld run
D Dirty or wet electrodes used when arc welding (1)

1.10 What does the X-ray test on a welded joint detect?
A External defects
B Internal defects
C Surface defects
D Visual defects

QUESTION 2: SAFETY
2.1 Which TWO safety precautions must be observed when working with a coil spring compressor? (2)
2.2 State THREE safety precautions that should be observed before pressing a bearing from a shaft using a hydraulic press. (3)
2.3Thabo uses a beam-bending tester to determine the degree of deflection of a work piece. State TWO safety precautions to be considered when using the beam-bending tester. (2)
2.4 Name ONE distinct safety precaution when using EACH of the following items of testing equipment:
2.4.1 Brinell tester (1)
2.4.2 Gear and bearing puller (1)
2.4.3 Torsion tester (1) [10]

QUESTION 3: TOOLS AND EQUIPMENT
3.1 Give TWO reasons for low fuel pressure. (2)
3.2Which precision measuring instrument is used to measure the following accurately:
3.2.1 The depth of a blind hole (1)
3.2.2 The pitch diameter of a V-screw thread (1)
3.3 A depth micrometer reading is shown in FIGURE 3.1. The micrometer is extended with a 50–75 mm interchangeable rod. Give the complete reading with the unit.

QUESTION 4: MATERIALS
4.1 Name TWO properties of EACH of the following structures of steel:
4.1.1 Cementite (2)
4.1.2 Pearlite (2)

QUESTION 5: TERMINOLOGY
5.1 A spur gear with 118 teeth must be cut on a universal milling machine. Calculate the indexing required to cut this gear with the help of a Cincinnati dividing head. (3)
5.2 Use simple line sketches to explain the difference between up-cut milling and down-cut milling on a milling machine. Indicate the work-piece feed and cutter rotation. (4)
5.3 A tapered gib-head key must be made to fit a 102 mm diameter shaft. Calculate the following key dimensions:
5.3.1 The width of the key (2)
5.3.2 The thickness of the key (2)
5.3.3 The length of the key (2)
5.3.4 The thickness of the key at the smaller end (4)

QUESTION 6: JOINING METHODS
6.1 What welding defect is described as non-metallic solids trapped in the weld metal? (1)
6.2 Name FOUR defects that may be observed during visual inspections. (4)
6.3State TWO causes of incomplete penetration in a welded joint. (2)
6.4 Name TWO measures to prevent a lack of fusion in a welded joint (2)

QUESTION 7: FORCES
7.1 Four pulling forces of 1,2 kN, 2 kN, 3,4 kN and 1,8 kN are acting on the same point, as shown in FIGURE 7.1 below. Determine, by means of calculations, the magnitude and direction of the resultant of the system of forces.

QUESTION 8: MAINTENANCE
8.1 Define preventative maintenance. (2)
8.2Why is it important to ensure that a machine is switched off and locked out when doing maintenance on belt drives? 2)
8.3 What is clutch-pedal free play? (2)
8.4 What is meant by the term viscosity index? (1)
8.5 Give TWO reasons why the clutch plate in a motor vehicle’s clutch assembly is replaced. (2)

QUESTION 9: SYSTEMS AND CONTROL
9.1 FIGURE 9.1 below shows a gear-drive system. Driver gear A on the shaft of the electric motor has 18 teeth that mesh with gear B, with 36 teeth, on a countershaft. There is another driver gear, C, with 16 teeth, on this countershaft, which meshes with a gear D, with 46 teeth, on the output shaft.