# Mechanical Technology Grade 12 NSC November 2012 QP (Eng)

> Grade 12 Mechanical Technology question paper from the NSC November Exam 2012 (English), 22 pages. Read online or download the free PDF.

- Page: https://www.hlayiso.com/library/mechanical-technology-nov-2012-eng/3fa45f1b-35d7-4873-bb36-3911c96d95bb
- Updated: 2026-09-27
- Subject: Mechanical Technology
- Grade: Grade 12
- Document type: Question paper
- Year: 2012
- Exam period: NSC November Exam
- Curriculum: CAPS
- Pages: 22

Breadcrumbs: [Home](https://www.hlayiso.com/) › [Library](https://www.hlayiso.com/library) › [Grade 12](https://www.hlayiso.com/library/grade-12) › [Mechanical Technology](https://www.hlayiso.com/library/grade-12/mechanical-technology) › [Mechanical Technology Grade 12 NSC November 2012 QP (Eng)](https://www.hlayiso.com/library/mechanical-technology-nov-2012-eng/3fa45f1b-35d7-4873-bb36-3911c96d95bb)

## About this document

Mechanical Technology · Grade 12 · NSC November Exam · 2012. Question paper, 22 pages. Read online or download the PDF.

Read it free online on the page above; download the PDF from there.

## Document text

Text extracted from the PDF. Layout, diagrams and tables may not survive extraction.

### Page 1

Downloaded from hlayiso.com

                                  GRAAD 12

                                 NATIONAL
                            SENIOR CERTIFICATE

                                  GRADE 12

                         MECHANICAL TECHNOLOGY

                                NOVEMBER 2012

MARKS: 200

TIME: 3 hours

        This question paper consists of 17 pages and a 5-page formula sheet.

Copyright reserved                                                     Please turn over

### Page 2

Downloaded from hlayiso.com
Mechanical Technology                      2                              DBE/November 2012
                                          NSC

INSTRUCTIONS AND INFORMATION

1.        Write your centre number and examination number in the spaces provided on
          the ANSWER BOOK.

2.        Read ALL the questions carefully.

3.        Answer ALL the questions.

4.        Answer QUESTION 1 on the inside of the front cover page of the ANSWER
          BOOK. Choose an answer and make a cross (X) in the block (A–D) next to
          the question number (1.1–1.20) in the ANSWER BOOK.

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 final answers to TWO decimal
          places.

8.        Candidates may use non-programmable scientific calculators and drawing
          instruments.

9.        The value of gravitational force should be taken as 10 m/s2.

10.       All dimensions are in millimetres, unless stated otherwise in the question.

11.       Write neatly and legibly.

12.       Use the criteria below to assist you in managing your time.

          QUESTION                  CONTENT COVERED               MARKS                TIME
             1           Multiple-choice questions                  20               18 minutes
             2           Tools and Equipment                        20               18 minutes
             3           Materials                                  20               18 minutes
             4           Safety, Terminology and Joining Methods    50               45 minutes
             5           Maintenance and Turbines                   40               36 minutes
             6           Forces, Systems and Control                50               45 minutes
                                                            TOTAL  200              180 minutes

Copyright reserved                                                             Please turn over

### Page 3

Downloaded from hlayiso.com
Mechanical Technology                       3                             DBE/November 2012
                                           NSC

QUESTION 1: MULTIPLE-CHOICE QUESTIONS

Various options are provided as possible answers to the following questions. Choose
the answer and make a cross (X) in the block (A–D) next to the question number
(1.1–1.20) on the inside of the front cover page of the ANSWER BOOK.

Example:

                     QUESTION                    OPTIONS
                         1.21          A         B      C       D

1.1       What is the advantage of down-cut milling?

          A      The strain on the arbor and cutter is less.
          B      Finish obtained is finer.
          C      More vibration is experienced.
          D      Built-up pressure is developed.                                                  (1)

1.2       Which ONE of the following safety procedures does NOT relate to the
          cylinder leakage tester?

          A      Use water to remove dust around the spark-plug area.
          B      Clean and remove the oil filler cap.
          C      Do not exceed the prescribed pressure in the test cylinder.
          D      The tester must fit properly and be well tightened in the spark-plug hole
                 or injector hole.                                                                (1)

1.3       What is the function of a gas analyser?

          A      Analyse inlet gases
          B      Analyse oil gases
          C      Analyse fuel gases
          D      Analyse exhaust gases                                                            (1)

1.4       The main reason for using a torsion tester is to measure the ability of metal to
          … without breaking.

          A      bend
          B      twist
          C      elongate
          D      shorten                                                                          (1)

1.5       Alloys can …

          A      reduce electrical conductivity.
          B      increase resistance to corrosion.
          C      reduce strength and hardness.
          D      alter insulation properties.                                                     (1)

Copyright reserved                                                             Please turn over

### Page 4

Downloaded from hlayiso.com
Mechanical Technology                      4                               DBE/November 2012
                                          NSC

1.6       Thermosetting plastic materials are materials that …

          A      can be stretched and return rapidly to their original shape.
          B      cannot be softened and reshaped by reheating.
          C      soften under heat and become hard when cooled.
          D      stay soft after reheating.                                                        (1)

1.7       Identify the type of milling cutter shown in FIGURE 1.1 below.

                                           FIGURE 1.1

          A      Dovetail slot cutter
          B      Convex cutter
          C      Cylindrical/Helical cutter
          D      Single corner rounding cutter                                                     (1)

1.8       Which lathe operation is shown in FIGURE 1.2 below?

                                           FIGURE 1.2

          A      Diameter turning
          B      Thread cutting
          C      Facing off
          D      Boring                                                                            (1)

1.9       Upcut milling is also known as …

          A      gang milling.
          B      slot milling.
          C      climb milling.
          D      conventional milling.                                                             (1)

1.10      What is the reason for using a free-bend test?

          A      To measure the ductility of the weld metal
          B      To test the skill of the welder
          C      To train welders
          D      To approve welds according to certain standards                                   (1)

Copyright reserved                                                              Please turn over

### Page 5

Downloaded from hlayiso.com
Mechanical Technology                       5                             DBE/November 2012
                                           NSC

1.11      What is the advantage of a helical cutter?

          A      Vibration experienced by the machine is more.
          B      Narrow cuts may be made.
          C      No side thrusts due to sliding action of the cutter.
          D      Wider cutters may be used.                                                        (1)

1.12      Tensile stress can be defined or described as an internal force in a material
          resisting …

          A      a shearing load.
          B      a pulling load.
          C      a pushing load.
          D      any load.                                                                         (1)

1.13      What is understood by the term Young's modulus?

          A      The force value required to produce a unit area in a tensile test
                 specimen
          B      The ratio between stress and strain in a metal, provided that the limit of
                 elasticity is not exceeded
          C      A measurement of the extension or contraction of material due to the
                 load experienced
          D      A ratio of the deformation by application of an external force                    (1)

1.14      Which step in adjusting the tension in the chain of a chain drive does
          FIGURE 1.3 below show?

                                       Centre distance

                                                S

                                            S

                        'S–S' min = 3%                 'S–S' max = 5%

                                         FIGURE 1.3

          A      Check the distance between the centres.
          B      Slacken the clamp bolts and screw the adjusting bolts in or out.
          C      Check the amount of slack in the chain. If it is between 3% and 5% it is
                 acceptable.
          D      Tighten the clamping bolts.                                                       (1)

Copyright reserved                                                              Please turn over

### Page 6

Downloaded from hlayiso.com
Mechanical Technology                     6                           DBE/November 2012
                                         NSC

1.15      Which procedure for removing a bearing is shown in FIGURE 1.4 below?

                                                      Ram

                                                      Inner ring

                                                      Bearing
                                                      Outer ring

                                                      Support strip

                                                      Shaft

                                       FIGURE 1.4

          A      Applying force to remove the shaft
          B      Applying force to the bearing
          C      Removing any rust from the shaft with emery paper
          D      Measuring the position of the bearing                                        (1)

1.16      Which ONE of the following is an advantage of V-belts?

          A      Can be used on loose pulleys
          B      May be used over long distances
          C      Able to absorb shock loads
          D      Operate at a high bearing pressure                                           (1)

1.17      What is the purpose of the linkage shown in FIGURE 1.5 below?

                                      FIGURE 1.5

          A      Converts rotary motion into oscillating motion
          B      Converts oscillating motion into rotary motion
          C      Converts reciprocating motion into rotary motion
          D      Converts rotary motion into reciprocating motion                             (1)

Copyright reserved                                                         Please turn over

### Page 7

Downloaded from hlayiso.com
Mechanical Technology                       7                                 DBE/November 2012
                                           NSC

1.18      Determine the distance 'D' moved by the follower for one full revolution of the
          pear-shaped cam shown in FIGURE 1.6 below, given that d 1 = 5 mm and
          d 2 = 12 mm.

                                                        Cam

          D
                     Follower
                                                                         d2          d1

                                          FIGURE 1.6

          A      7 mm
          B      17 mm
          C      5 mm
          D      12 mm                                                                                  (1)

1.19      What is understood by the term pressure ratio in turbochargers?

          A      The pressure that the turbocharger generates in the intake manifold
          B      The pressure that the turbocharger generates in the exhaust manifold
          C      The inlet pressure compared to the outlet pressure
          D      Decreased pressure in the exhaust manifold                                             (1)

1.20      The volumetric efficiency of a blower is the …

          A      ability to heat intake air.
          B      ability to cool exhaust air.
          C      ability to drive the blower.
          D      ability to fill the cylinder with air above atmospheric pressure.                      (1)
                                                                                                        [20]

Copyright reserved                                                                   Please turn over

### Page 8

Downloaded from hlayiso.com
Mechanical Technology                   8                            DBE/November 2012
                                       NSC

QUESTION 2: TOOLS AND EQUIPMENT

2.1       When a dry compression test was conducted on cylinder number one of a
          four-stroke, four-cylinder, spark-ignition engine the result was very low
          compared to the engine specifications. State THREE possible causes of the
          low compression in cylinder number one.                                            (3)

2.2       Define torsion.                                                                    (2)

2.3       FIGURE 2.1 below indicates a multimeter that is used to test different
          electrical components and circuits. Label parts A–E on the multimeter.

                                                        A

                                                            B

                                                            C

                                                            D

                                                            E

                                      FIGURE 2.1                                             (5)

2.4       The function of the cylinder leakage tester is to check whether the engine
          leaks gases from the cylinder during compression strokes. State THREE
          possible leakages during the cylinder leakage test and state the cause of
          each.                                                                              (6)

2.5       What does the abbreviation MAGS/MIGS stand for in welding equipment?               (2)

2.6       Name TWO gases that can be used in MAGS/MIGS welding.                              (2)
                                                                                             [20]

Copyright reserved                                                        Please turn over

### Page 9

Downloaded from hlayiso.com
Mechanical Technology                      9                            DBE/November 2012
                                          NSC

QUESTION 3: MATERIALS

3.1       Name ONE difference between non-ferrous metals and composites.                           (2)

3.2       FIGURE 3.1 below shows the results of a compressive strength test on two
          materials, A and B.

               Materials before test              A                      B

                                                 Force       =          Force

                  Materials after test
                                                   A                     B

                                           FIGURE 3.1

          3.2.1       Which of the materials, A or B, has the highest compressive
                      strength?                                                                    (1)

          3.2.2       Give a reason for the answer to QUESTION 3.2.1.                              (2)

3.3       Name THREE main classes/groups of carbon steel.                                          (3)

3.4       Name FOUR properties of carbon steel that will change when the carbon
          content is increased.                                                                    (4)

3.5       Choosing the most suitable material for a particular product requires you to
          have good knowledge of materials. State TWO uses and TWO properties of
          the following engineering materials:

          3.5.1       Duralumin                                                     (2 + 2)        (4)

          3.5.2       Polyvinyl chloride (PVC)                                      (2 + 2)        (4)
                                                                                                   [20]

Copyright reserved                                                              Please turn over

### Page 10

Downloaded from hlayiso.com
Mechanical Technology                      10                               DBE/November 2012
                                          NSC

QUESTION 4: SAFETY, TERMINOLOGY AND JOINING METHODS

4.1       State THREE safety precautions to be observed when operating a beam
          bending tester.                                                                           (3)

4.2       State THREE safety precautions to be observed when storing gas cylinders.                 (3)

4.3       Give TWO advantages of each of the following milling operations:

          4.3.1       Upcut milling                                                                 (2)

          4.3.2       Down-cut milling                                                              (2)

4.4       A gear with 63 teeth has to be machined on a milling machine.
          Use A = 60 or N = 60.

          4.4.1       Calculate the indexing required.                                              (4)

          4.4.2       Calculate the change gears required.                                          (5)

4.5       Calculate the feed in millimetres per minute of an 80 mm diameter cutter with
          14 teeth, operating at a cutter speed of 20 metres per minute and a feed of
          0,08 mm per tooth.                                                                        (7)

4.6       Mary is a quality controller who inspects welded joints on workpieces. She
          uses an ultrasonic test to determine whether the welds have any welding
          defects. Explain the principle of operation of the ultrasonic test on welded
          joints.                                                                                   (5)

4.7       State TWO possible causes and ONE preventive action for each of the
          following weld defects:

          4.7.1       Slag inclusion                                                 (2 + 1)        (3)

          4.7.2       Undercutting                                                   (2 + 1)        (3)

4.8       Which milling cutter can be used to cut the following profiles?

          4.8.1       Spur gear                                                                     (1)

          4.8.2       Groove                                                                        (1)

          4.8.3       Rack                                                                          (1)

          4.8.4       Blind hole                                                                    (1)

Copyright reserved                                                               Please turn over

### Page 11

Downloaded from hlayiso.com
Mechanical Technology                    11                           DBE/November 2012
                                        NSC

4.9       FIGURE 4.1 below shows a dividing head of a milling machine. Label parts
          A–E.

                E

                                                                       A

                                D

                                      FIGURE 4.1                                              (5)

4.10      State the TWO classes of milling cutters and give ONE example of each.              (4)
                                                                                              [50]

Copyright reserved                                                         Please turn over

### Page 12

Downloaded from hlayiso.com
Mechanical Technology                      12                             DBE/November 2012
                                          NSC

QUESTION 5: MAINTENANCE AND TURBINES

5.1       FIGURE 5.1 below shows a clutch and pressure-plate assembly.

                                                                 B
                             A

                                                                 C

                                                                 D

                                                                 E

                                                                 F
                                          FIGURE 5.1

          5.1.1       Label parts A–F in the clutch and pressure-plate assembly.                  (6)

          5.1.2       State TWO functions of the clutch plate in this clutch and pressure-
                      plate assembly.                                                             (4)

          5.1.3       Name THREE causes of slip in this clutch and pressure-plate
                      assembly.                                                                   (3)

          5.1.4       Name TWO types of clutches used in the engineering environment.             (2)

5.2       State THREE functions of lubricating oil.                                               (3)

5.3       State THREE guidelines for the maintenance of cutting fluid used in a lathe.            (3)

Copyright reserved                                                             Please turn over

### Page 13

Downloaded from hlayiso.com
Mechanical Technology                      13                           DBE/November 2012
                                          NSC

5.4       The performance of smaller engines can be improved by using superchargers
          (FIGURE 5.2).

                                                         C

                                                                                        C

                                                                                        D

                                              D
                                         FIGURE 5.2

          5.4.1       Identify the type of supercharger shown in FIGURE 5.2.                      (1)

          5.4.2       Label parts A–D.                                                            (4)

          5.4.3       Explain the operation of the supercharger shown in FIGURE 5.2.              (5)

          5.4.4       Name THREE advantages of superchargers.                                     (3)

5.5       Name THREE classifications of steam turbines.                                           (3)

5.6       State THREE advantages of gas turbines.                                                 (3)
                                                                                                  [40]

Copyright reserved                                                             Please turn over

### Page 14

Downloaded from hlayiso.com
Mechanical Technology                       14                             DBE/November 2012
                                           NSC

QUESTION 6: FORCES, SYSTEMS AND CONTROL

6.1       A hydraulic system is being used to lift a machine part into position. The
          specifications of the system are diagrammatically presented in FIGURE 6.1
          below.

                     Ø 38 mm
                                                                    Ø 175 mm
                      300 N

                                                                    Load = ?

                     Piston A

                                                                     Piston B

                                          FIGURE 6.1

          Determine the following by means of calculations:

          6.1.1        The fluid pressure in the hydraulic system when in equilibrium              (5)

          6.1.2        The load that can be lifted by piston B when a force of 300 N is
                       applied to piston A                                                         (6)

6.2       A steel spoke of a bicycle wheel has a cross-sectional area of 2,2 mm2 and
          a length of 300 mm. The nut of the spoke is tightened until the length
          increases by 0,2 mm. Determine, by means of calculations, the tensile force
          in the spoke material. Take Young's elasticity modulus for the spoke material
          as 245 GPa.                                                                              (9)

Copyright reserved                                                              Please turn over

### Page 15

Downloaded from hlayiso.com
  Mechanical Technology                       15                             DBE/November 2012
                                             NSC

6.3     FIGURE 6.2 shows a belt-drive system. A pulley with a diameter of 0,25 m
        drives a driven pulley with a diameter of 0,35 m. The driver pulley rotates at
        1 000 r/min. T 1 = 200 N and T 2 =90 N.

                       NDN = ? r/min
                       DDN = 0,35 m                            NDR = 1 000 r/min
                                                               DDR = 0,25 m

                                           FIGURE 6.2

            Determine by means of calculations:

            6.3.1       The rotation frequency of the driven pulley in r/min (revolutions per
                        minute)                                                                       (3)

            6.3.2       The power transmitted                                                         (3)

            6.3.3       The belt speed of the system in metres per second                             (3)

  Copyright reserved                                                               Please turn over

### Page 16

Downloaded from hlayiso.com
Mechanical Technology                        16                              DBE/November 2012
                                            NSC

6.4       FIGURE 6.3 shows a gear drive system. A driver gear on the shaft of an
          electric motor has 24 teeth and meshes with a gear on a counter shaft with
          40 teeth. On this counter shaft is another driver gear with 20 teeth that
          meshes with a gear with 48 teeth on a second counter shaft. The second
          counter shaft has a driver gear with 42 teeth which drives a gear with
          90 teeth on the output shaft.

                                                         Counter
              Electrical                                  shaft
              motor
                                                  48                 42
                               24
                                      Counter
                                       shaft
                                                                             Output shaft
                               40                 20

                                                                     90

                                           FIGURE 6.3

      Calculate:

      6.4.1          The rotation frequency of the output shaft if the electric motor
                     rotates at 1 440 r/min                                                          (4)

      6.4.2          The velocity ratio between the input and output shaft                           (2)

Copyright reserved                                                                Please turn over

### Page 17

Downloaded from hlayiso.com
Mechanical Technology                        17                                DBE/November 2012
                                            NSC

6.5       A differential wheel-and-axle lifting machine is shown in FIGURE 6.4 below.
          A load of 2,4 kN is lifted when an effort of 400 N is applied. The diameters of
          the pulleys are 210 mm, 160 mm and 140 mm respectively.

                                                                             d1 = 140   d2 = 160   D = 210

                         400 N                2,4 kN

                                           FIGURE 6.4

          Determine by means of calculations:

          6.5.1       The mechanical advantage                                                               (2)

          6.5.2       The velocity ratio                                                                     (3)

          6.5.3       The mechanical efficiency of the machine                                               (2)

6.6       A single-plate friction clutch transmits a maximum torque of 336 Nm. The
          clutch plate has friction material on both sides with a friction co-efficient of 0,4.
          The total applied force on the friction surfaces is 3,5 kN.

          Determine by means of calculations:

          6.6.1       The effective diameter of the clutch plate in millimetres                              (5)

          6.6.2       The power transmitted at 3 200 r/min                                                   (3)
                                                                                                             [50]

                                                                                                   TOTAL:    200

Copyright reserved

### Page 18

Downloaded from hlayiso.com
Mechanical Technology                              1                                  DBE/November 2012
                                                  NSC

          FORMULA SHEET FOR MECHANICAL TECHNOLOGY – GRADE 12

1.     BELT DRIVES

                                          πDN
       1.1              Belt speed =
                                           60

                                          π ( D + t )× N
       1.2              Belt speed =                     (t = belt thickness)
                                                60

       1.3              Belt mass = Area × length × density (A = thickness × width)

                                            Diameter of driven pulley
       1.4              Speed ratio =
                                            Diameter of driver pulley

       1.5              N 1 D1 = N 2 D2

                                           π( D + d ) ( D - d )2
       1.6              Open-belt length =           +           + 2c
                                               2         4c

                                                   π( D + d ) ( D + d )2
       1.7              Crossed -belt length =               +           + 2c
                                                       2          4c

                                           2π NT
       1.8              Power ( P ) =
                                             60

                                                              T1
       1.9              Ratio of tight side to slack side =
                                                              T2

                                           (T1 − T2 ) π D N
       1.10             Power ( P ) =                              where T1 = force in the tight side
                                                  60

                                              T1
       1.11             Width =
                                   permissible tensile force

Copyright reserved

### Page 19

Downloaded from hlayiso.com
Mechanical Technology                                 2                            DBE/November 2012
                                                     NSC

2.     FRICTION CLUTCHES

        2.1          Torque ( T ) = µWnR
                               µ = coefficient of friction
                                      W = total force
                                      n = number of friction surfaces
                                      R = effective radius

        2.2                                 2 π NT
                        Power ( P ) =
                                              60

3.     STRESS AND STRAIN

                                    Force                  F
        3.1           Stress =                 or ( σ =      )
                                    Area                   A

                                           change in length ( ΔL )
        3.2          Strain ( ε ) =
                                            original length ( L )

                                                      stress            σ
        3.3          Young' s mod ulus ( E ) =                   or (     )
                                                      strain            ε

                                    πd 2
       3.4               Ashaft =
                                     4

                                 π(D 2 − d 2 )
       3.5               Apipe =
                                      4

4.     HYDRAULICS

                                                Force ( F )
       4.1              Pressure ( P ) =
                                                Area ( A )

                         F1 F2
       4.2                 =
                         A1 A2

       4.3              Work done = force × distance

       4.4              Volume = Cross-sectional area × stroke length ( l or s )

Copyright reserved

### Page 20

Downloaded from hlayiso.com
Mechanical Technology                              3                           DBE/November 2012
                                                  NSC

5.     WHEEL AND AXLE

                                                  effort distance   2D
       5.1              Velocity ratio ( VR ) =                   =
                                                  load distance d 2 − d 1

                                                           Load ( W )
       5.2              Mechanical advantage ( MA ) =
                                                           Effort ( F )

                                                            MA
       5.3              Mechanical efficiency ( ηmech ) =      × 100%
                                                            VR
6.     LEVERS
                                                           Load ( W )
       6.1              Mechanical advantage ( MA ) =
                                                           Effort ( F )

       6.2              Input movement ( IM ) = Effort × distance moved by effort

       6.3              Output movement ( OM ) = Load × distance moved by load

                                                   Input movement
       6.4              Velocity ratio ( VR ) =
                                                  Output movement

7.     SCREW THREADS

       7.1              Pitch diameter = Outside diameter − ½ pitch

       7.2              Pitch circumference = π × pitch diameter

       7.3              Lead = pitch × number of starts

                                                          Lead
       7.4              Helix angle : tan θ =
                                                   Pitch circumference

       7.5              Leading tool angle = 90° – (helix angle + clearance angle)

       7.6              Following/Trailing angle = 90° + (helix angle – clearance angle)

                                            height
       7.7              Number of turns =
                                             lead

Copyright reserved

### Page 21

Downloaded from hlayiso.com
Mechanical Technology                                4                                 DBE/November 2012
                                                    NSC

8.     GEAR DRIVES

                                           2 π NT
       8.1              Power ( P ) =
                                             60

                                          Product of the number of teeth on driven gear
       8.2              Gear ratio =
                                          Product of the number of teeth on driver gear

                         N Input       Product of the number of teeth on driven gear
       8.3                         =
                        N Output       Product of the number of teeth on driver gear

       8.4              Torque = force × radius

       8.5              Torque transmitted = gear ratio × input torque

                                             Pitch-circle diameter ( PCD )
       8.6              Module ( m ) =
                                                 Number of teeth ( T )

       8.7              N 1T1 = N 2T2        and        N1 D1 = N 2 D2

                                                               circular pitch ( CP ) × number of teeth ( T )
       8.8              Pitch-circle diameter ( PCD ) =
                                                                                     π

       8.9              Outside diameter ( OD ) = PCD + 2 module

       8.10             Addendum ( a ) = module ( m )

       8.11             Dedendum ( b ) = 1,157 m                   or      Dedendum ( b ) = 1,25 m

       8.12             Cutting depth ( h ) = 2,157 m              or      Cutting depth ( h ) = 2,25 m

       8.13             Clearance ( c ) = 0,157 m                  or      Clearance ( c ) = 0,25

       8.14             Circular pitch ( CP ) = m × π
                                                    N input
       8.15             VR (Velocity ratio) =
                                                    N output

Copyright reserved

### Page 22

Downloaded from hlayiso.com
Mechanical Technology                                  5                                           DBE/November 2012
                                                      NSC

9.     CINCINNATI DIVIDING HEAD TABLE FOR THE MILLING MACHINE

                                                       Hole circles
         Side 1      24        25      28        30         34        37        38         39      41     42        43
         Side 2      46        47      49        51         53        54        57         58      59     62        66

                                                 Standard change gears
         24 x 2       28        32      40            44         48        56         64         72      86         100

                                      40
       9.1     Simple indexing =         ( where n = number of divisions )
                                       n

       9.2     Change gears:

                  Dr              40                   Dr (A − n) 40                            Dr             40
                     = ( A − n )×           or            =      ×                   or            = (N − n) ×
                  Dv               A                   Dv    A     1                            Dv             N

10.    CALCULATIONS OF FEED

       10.1    Feed (f) = f 1 × T × N

               Where: f = feed in millimetres per minute

                          f 1 = feed per tooth in millimetres

                        T = number of teeth on cutter

                        N = number of revolutions of cutter per minute

       10.2    Cutting speed (V) = π × D × N

               Where: D = diameter of the cutter in metres

Copyright reserved

## Related documents

- [Mechanical Technology Nov 2012 Memo Eng](https://www.hlayiso.com/library/mechanical-technology-nov-2012-memo-eng/0cd2c7e3-61d6-4a21-80c4-178cd05b4dad) — Mechanical Technology · Memo · 2012 · Eng
- [MCHT S12 QP Eng](https://www.hlayiso.com/library/mcht-s12-qp-eng/d5abbe15-b88d-4110-9403-40ef28f02d1a) — Mechanical Technology · QP · 2012 · Eng
- [MCHT S12 QP Afr](https://www.hlayiso.com/library/mcht-s12-qp-afr/95788f70-d93f-4ba8-b075-b0d0daf1c798) — Mechanical Technology · QP · 2012 · Afr
- [Mechanical Technology Nov 2023 (Fitting and Machining) Afr](https://www.hlayiso.com/library/mechanical-technology-nov-2023-fitting-and-machining-afr/ec5f897b-937f-4bae-aad9-e566a280b360) — Mechanical Technology · QP · 2023 · Afr
- [Mechanical Technology Nov 2023 (Automotive) Afr](https://www.hlayiso.com/library/mechanical-technology-nov-2023-automotive-afr/b8922567-d93f-4dcd-9279-3b4c4bd034b9) — Mechanical Technology · QP · 2023 · Afr
- [Mechanical Technology Nov 2023 (Welding & Metal Work) Eng](https://www.hlayiso.com/library/mechanical-technology-nov-2023-welding-metal-work-eng/b9535038-8936-48a1-afcd-0ab67f8f03aa) — Mechanical Technology · QP · 2023 · Eng

## More from Grade 12 Mechanical Technology

- [Gr 12 Weld Met ATP 2023-24](https://www.hlayiso.com/library/gr-12-weld-met-atp-2023-24/8ecc8de5-c625-4611-9b94-1f3fd325e05d) — ATP
- [MECH TECH GR12 MEMO SEPT2024 (Welding & Metalwork) Afrikaans](https://www.hlayiso.com/library/mech-tech-gr12-memo-sept2024-welding-metalwork-afrikaans/aadd113c-5a3b-4f4d-a4c4-3a80cd86f882) — Memo · 2024 · Afr
- [MECHANICAL TECH (Auto) GR12 MEMO SEPT2024 Afrikaans](https://www.hlayiso.com/library/mechanical-tech-auto-gr12-memo-sept2024-afrikaans/2f874dd1-8c03-49a9-8c70-41ac528693d0) — Memo · 2024 · Afr
- [MECH TECH MEMO GR12 SEPT Fitting English](https://www.hlayiso.com/library/mech-tech-memo-gr12-sept-fitting-english/6c8e4f19-8a49-43c9-a4af-dbf620595837) — Memo · 2024 · Eng
- [Mechanical Technology Nov 2024 (Fitting and Machining) MG Eng](https://www.hlayiso.com/library/mechanical-technology-nov-2024-fitting-and-machining-mg-eng/ed5ab6d3-088f-425c-ade8-86186a031594) — Memo · 2024 · Eng
- [Mechanical Technology May-June 2024 (Fitting and Machining) MG Afr](https://www.hlayiso.com/library/grade-12-mechanical-technology-2024-nsc-june-exam-memorandum-afrikaans/03c703c8-8125-4d5a-a124-37013b381c7a) — Memo · 2024 · Afr

## Collection

- [Grade 12 past papers](https://www.hlayiso.com/grade-12/past-papers)

---

Hlayiso: free CAPS and IEB past papers, memos, notes and study guides for South African learners. When citing, link the page URL above, not a PDF or /api/ URL.
