Machine Drawing MEC-304. Dr. Shankar Sehgal Asst. Professor in Mech. Engg. UIET, Panjab University, Chandigarh

Transcription

1 Machine Drawing MEC-304 Dr. Shankar Sehgal Asst. Professor in Mech. Engg. UIET, Panjab University, Chandigarh

2 Standard Abbreviations

3 Standard Abbreviations

4 Standard Abbreviations

5 Standard Abbreviations

6 Tolerances and Fits

7 Tolerances and Fits

8

9

10

11

12

13

14

15

16

17

18 Tolerances and Fits

19 Tolerances and Fits

20 Tolerances and Fits

21 Tolerancing individual dimensions

22 Tolerancing individual dimensions

23 Tolerancing individual dimensions

24 Tolerancing individual dimensions

25 Tolerancing individual dimensions

26 Fits

27 Fits

28 Fits

29 Fits

30 Fits

31 Fits

32 Shaft basis system

33 Hole basis system

34 Machining symbols

35 Machining symbol Any machining method may be used

36 Machining symbol Circle means: Material removal not permitted

37 Machining symbol Bar means: Material removal by machining is required

38 Machining symbol Milled Any special machining characteristics are mentioned on the extra horizontal line

39 Surface finish Peak-to-valley height Reference profile Actual profile Datum profile Mean profile

40 Surface finish parameters Actual profile: It is the profile of the actual surface obtained by finishing operation Reference profile: It is the profile to which the irregularities of the surface are referred to. It passes through the highest point of the actual profile.

41 Surface finish parameters Datum profile: It is the profile, parallel to the reference profile. It passes through the lowest point B of the actual profile. Mean profile: It is that profile, within the sampling length chosen (L), such that the sum of the material filled areas enclosed above it by the actual profile is equal to the sum of the material-void areas enclosed below it by the profile.

42 Surface finish parameters Peak-to-valley height: It is the distance from the datum profile to the reference profile. Mean roughness index: It is the arithmetic mean of the absolute values of the heights h i between the actual and mean profiles. It is given by,

43 Surface roughness number

44 Surface finish symbols

45 Measurement of surface finish 1. Straight edge 2. Surface guage 3. Optical flat 4. Tool maker s microscope 5. Profilometer 6. Profilograph 7. Talysurf

46 Surface finish symbols

47 Surface finish symbols

48 Surface finish symbols

49 Welding symbols

50 Elementary welding symbols

51 Elementary welding symbols

52 Elementary welding symbols

53 Supplementary welding symbols

54 Combination of elementary and supplementary welding symbols

55 Welding symbols

56 Indication of edge preparation Dotted line is on LOWER side. This means that LOWER plate is to be prepared Welding symbol on continuous line (and not on dotted line). This means that weld is to be made on arrow side (and not on the other side).

57 Weld dimensions a = throat thickness z = leg length

58 Welding process designations

59 Screw threads

60 Screw threads

61 Screw threads

62 Forms of screw threads Metric screw thread

63 Forms of screw threads Metric screw thread

64 Forms of screw threads

65 Forms of screw threads

66 Forms of screw threads

67 Forms of screw threads

68 Forms of screw threads

69 Forms of screw threads

70 Thread designation M 10 x 1.25 means Metric thread of nominal diameter 10 mm and pitch 1.25 mm (Fine series) M 10 means Metric thread of nominal diameter 10 mm and pitch 1.5 mm (Coarse series) SQ 40 x 10 means SQuare thread of nominal diameter 40 mm and pitch 10 mm ACME 40 x 8 means ACME thread of nominal diameter 40 mm and pitch 8 mm WORM 40 x 10 means WORM thread of nominal diameter 40 mm and pitch 10 mm

71 Left hand thread

72 Right hand thread

73 Conventional representation of threads Crests of threads are indicated by a continuous thick line and the roots, by a continuous thin line. For hidden screw threads, the crests and roots are indicated by dotted line For threaded parts in section, hatching should be extended to the line defining the crest of the thread. In the view from side, the threaded roots are represented by a portion of a circle, drawn with a continuous thin line, of length approximately threequarters of the circumference.

74 Conventional representation of threads The limit of useful length of screw threads is represented by a continuous thick line or a dotted line, depending on its visibility. The length up to which the incomplete threads are formed beyond the useful limit, is known as a run-out. It is represented by two inclined lines.

75 Conventional representation of threads continuous thick line continuous thin line

76 Conventional representation of threads dotted line

77 Schematic representation of threaded parts - V-threads

78 Schematic representation of threaded parts - Square-threads

79 Bolted joint

80 Hexagonal nut

81 Hexagonal nut

82 Hexagonal nut

83 Hexagonal nut

84 Method of drawing hexagonal nut 1. Draw the top view by drawing a circle of diameter, W and describe a regular hexagon on it, by keeping any two parallel sides of the hexagon, horizontal. 2. Project the view from the front, and the view from side, and mark the height equal to D. 3. With radius R, draw the chamfer arc passing through the point 1 in the front face. 4. Mark points 4 and 5, lying in-line with 2 and Locate points 8,9 on the top surface, by projecting from the view from above. 6. Draw the chamfers 4 8 and Locate points 6 and 7, lying at the middle of the outer two faces. 8. Draw circular arcs passing through the points 4, 6, 2 and 3, 7, 5, after determining the radius R1 geometrically. 9. Project the view from the side and locate points 10, 11 and Mark points 13 and 14, lying at the middle of the two faces (view from the side). 11. Draw circular arcs passing through the points 10, 13, 11 and 11, 14, 12, after determining the radius R2 geometrically.

85 Hexagonal headed bolt

86 Hexagonal headed bolt with nut and washer

87 Square nut

88 Square nut

89 Square nut

90 Square headed bolt

91 Stud bolt or stud

92 Nuts

93 Screws

94 Lock nut

95 Lock nut

96 Locking by split pin

97 Locking by castle nut

98 Wile s lock nut

99 Locking by set screw

100 Pipe fittings

101 Pipe fittings

102 Cotter Joint

103 Cotter Joint

104 Knuckle Joint

105 Knuckle Joint

106 Muff coupling

107 Muff coupling

108 Flange coupling

109 Flange coupling

110 Footstep bearing

111 Front view of footstep bearing

112 Top view of footstep bearing

113 Footstep bearing

114 Footstep bearing

115 Footstep bearing

116 Plummer block

117 Front view of plummer block

118 Top view of plummer block

119 Plummer block

120 Screw jack

121 Screw jack

122 I.C. engine piston

123 I.C. engine connecting rod

124 I.C. engine connecting rod

125 Lathe tail stock