Mechanical Technology Grade 12 IEB 2017 Information Sheet

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MECHANICAL TECHNOLOGY – FORMULA SHEET Page i of iv FORMULA SHEET 1. BELT DRIVES 1.1 N1 × D1 = N2 × D2 DN 1.2 Belt speed = where N is in r/min 60  D  t   N 1.3 Belt speed = (t = belt thickness) 60 1.4 Belt mass = area × length × density (A = thickness × width) diameter of driven pulley 1.5 Speed ratio = diameter of driving pulley 1.6 Belt length (flat belt) = [(D + d)× 1,57] + 2 × centre distance  D  d D  d  2c 2 2 1.7 Open belt length =  2 4c  D  d D  d  2c 2 2 1.8 Crossed belt length =  2 4c T1 1.9 Ratio between tight side and slack side = T2 1.10 Power (P) =  T1  T2  DN where N is in r/min 60 T1 = force in tight side T2 = force in slack side T1 – T2 = effective force (Te) 1.11 Power (P) = (T 1 – T 2 ) × V where V = belt speed in m/s 2NT 1.12 Power (P) = where N is in r/min 60 T1 1.13 Width = permissable tensile force 2. STRESS AND STRAIN force  F 2.1 Stress = or     area  A change in length( L ) 2.2 Strain (ɛ) = original length(L) IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MECHANICAL TECHNOLOGY – FORMULA SHEET Page ii of iv stress  2.3 Young’s modulus (E) = or  strain   d2 2.4 Area of a round bar = A = 4 (D2  d2 ) 2.5 Area of a pipe = A = 4 2.6 Area of a square bar = A = L2 or A = L × W 3. HYDRAULICS force F  3.1 Pressure (P) = area (A) 3.2 Volume = (cross-sectional area) × stroke length 3.3 Work done = force × distance 4. KEYS AND KEYWAYS diameter of shaft 4.1 Width of key = 4 diameter of shaft 4.2 Thickness of key = 6 4.3 Length of key = 1,5 × diameter of shaft 4.4 Standard taper for taper key = 1 in 100 or 1 : 100 5. LEVERS load  W  5.1 Mechanical advantage (MA) = effort F  input movement 5.2 Velocity ratio (VR) = output movement 5.3 Input movement (IM) = effort × distance moved by effort 5.4 Output movement (OM) = load × distance moved by load 6. GEAR DRIVES 6.1 N1 × D1 = N2 × D2 2NT 6.2 Power (P) = 60 IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MECHANICAL TECHNOLOGY – FORMULA SHEET Page iii of iv product of number of teeth on driven gears 6.3 Gear ratio = product of number of teeth on driving gears Ninput product produk of die van number getaloftande teethop on driven gedrewe gears ratte 6.4 inset  Noutput N uitset produkofvan product die of number getal tande teeth on op dryfratte driving gears 6.5 Torque = force × radius 6.6 Torque transmitted = gear ratio × input torque pitch  circle diameter PCD  6.7 Module (m) = number of teeth  T  6.8 N1T1 = N2T2 circular pitch  CP   number of teeth  T  6.9 Pitch-circle diameter (PCD) =  6.10 Pitch-circle diameter (PCD) = m × T 6.11 Outside diameter (OD) = m(T + 2) 6.12 Outside diameter (OD) = Pitch-circle diameter (PCD) + 2 module 6.13 Addendum = module (m) 6.14 Dedendum = 1,157 m or Dedendum = 1,25 m 6.15 Cutting depth = 2,157 m or Cutting depth = 2,25 m 6.16 Clearance = 0,157 m or Clearance = 0,25 m 6.17 Circular pitch (CP) = m ×   SSD AA (PCD)  SSD BB (PCD) 6.18 Centre distance between gear A and gear B =  2 2 7. SCREW THREADS 1 7.1 Pitch diameter = outside diameter – pitch 2 7.2 Pitch circumference =  × pitch diameter 7.3 Lead = pitch × number of starts 7.4 Height of screw thread = 0,866 × pitch 7.5 Depth of screw thread = 0,613 × pitch IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MECHANICAL TECHNOLOGY – FORMULA SHEET Page iv of iv 8. INDEXING 8.1 Cincinnati dividing head table for milling machine Cincinnati index plate 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 40 8.2 Indexing = (where n = number of divisions) n IEB Copyright © 2017