NATIONAL CERTIFICATE (VOCATIONAL) NOVEMBER

Transcription

1 MARKING GUIDELINE NATIONAL CERTIFICATE (VOCATIONAL) NOVEMBER 2009 NQF LEVEL 2 This memorandum consists of 7 pages.

2 MARKING GUIDELINE -2- NC930(E)(N25)V QUESTION 1: GENERAL. 1.1 TRUE OR FALSE TRUE TRUE FALSE FALSE FALSE 1.2 CHOOSE THE CORRECT ANSWER A B D C A 1.3 FILL IN THE MISSING WORDS HACKSAW. HEAT. STARE. OHMETER. JENNY CALLIPERS. 1.4 GIVE ONE WORD VICE GRIP ENGINEER S SQUARE. TELESCOPIC GAUGE. MASS. RADIUS. [20] QUESTION 2: ENGINEERING HAND TOOLS HANDLE. SCREW. LOOSE JAW. FIXED JAW. BODY.

3 MARKING GUIDELINE -3- NC930(E)(N25)V LONG NOSE PLIERS. INTERNAL CIRCLIP PLIERS A wire stripper can be used to strip the plastic insulation off electric wires. A taper tap can be used to start a thread. 2.4 Torque wrench The thread of the vice will get damaged and/or the body of the vice will be damaged. Tighten the vice by using his/her body weight so that the vice cannot be over-tightened. Check whether the welds on the legs are still intact or not. I would re-weld the legs of the work-bench or purchase a new one if the old one is beyond repair. 2.7 Oil the moving parts regularly. Clean the gripping surface. Correct the adjustment before applying force. (2) [ ANY TWO ] 2.8 It will damage the head. [17] QUESTION 3: ENGINEERING POWER TOOLS. 3.1 Portable Electric hand drill. Air Compressor Portable or angle grinder. Pencil grinder. Bench and pedestal grinding machine. Pneumatic drills. Pneumatic grinders. Hydraulic press. Band saw. [ ANY FIVE ] A bench grinding machine.

4 MARKING GUIDELINE -4- NC930(E)(N25)V A - Wheel guard. B - Grinding wheel. C - Grinding rest. D - Motor E - Base A hydraulic press is used to press sheet metal into the required shapes. A milling machine is used to make flat surfaces on metal. A lathe is used for boring or drilling holes, and for cutting inside and outside screw threads. Electrical Pneumatic Hydraulic Bench drilling machine. Blow gun. Band saw. (3) [17] QUESTION 4: ENGINEERING MEASURING EQUIPMENT Combination set Spirit level Graduated Scale A hydrometer is used to measure the density of liquids. An Engineer s square is used to measure, check and draw right angles. A ring gauge and a receiver gauge can be used to check the dimensions of a shaft, and can check as many radii as needed at once. A receiver gauge can detect if the component is bowed along its length, which a ring gauge cannot do. 4.4 Do not look directly / stare into the laser beam. Do not shine the laser into a person s eyes. [ ANY ONE ] The mercury can be highly toxic when it comes into contact with the skin, and/or the glass may cut the student. I would apply first aid (use gloves to bandage the student) if the student is cut by the glass and / or seek medical advice if the student has accidentally come into contact with the mercury.

5 MARKING GUIDELINE -5- NC930(E)(N25)V 4.6 Keep the feeler gauge free of dust and sand. Oil the feeler gauge lightly to prevent rusting. Slide the blades back into the protective holder after use. Prevent the thinner blades from kinking. [ ANY TWO ] (2) [12] QUESTION 5: ENGINEERING PRECISION MEASURING EQUIPMENT Dial Calipers. Electronic Calipers. Spindle. Frame. 5.3 A spring balance is used to measure weight. 5.4 An external micrometer and a digital micrometer are both used to measure the diameter of round bars and the thickness of sheet metal, except that the reading on the digital micrometer is displayed on a LCD Screen. (2) [7] QUESTION 6: SI UNITS MEASUREMENT Cubic meter. Square meter. 6.2 Speed is the distance travelled in a given time. Velocity is the rate of change of distance (speed) in a given direction. 6.3 TORQUE = FORCE DISTANCE = 20N X 3 M The reading on the torque wrench will be = 60NM [7]

6 MARKING GUIDELINE -6- NC930(E)(N25)V QUESTION 7: ENGINEERING MARKING OFF EQUIPMENT Steel beam trammel (Beam compass). Dividers. 7.2 Step 1. Mark and dot punch the centre of the circle. Step 2. Set the divider to the correct radius and click one leg into the ruler engraving. Step 3. Place one leg of the divider into the dimple created by the dot punch, and rotate the divider by another leg on the piece of metal. 7.3 Prevent the angle plate from falling, it will break. Do not handle it rough, it will crack. Keep the working surfaces oiled lightly to prevent rust. [ ANY TWO ] (2) [7]

7 MARKING GUIDELINE -7- NC930(E)(N25)V QUESTION 8: BASIC ENGINEERING DRAWING