Simmons C.H., Dennis E.M. Manual of Engineering Drawing
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140 Manual of Engineering Drawing
5
Plunger
66
Sphere
φ
19
22
22
M10 × 1.5
φ
19
5 Turns of Ø3 wire
ground flat at each
end
25
Free length
6
Spring
370
φ
10
φ
19
7
Arm pivot
φ
10
φ
19
453
Cam pivot
8
Note: On assembly, fit
a suitable washer over
each pivot and drill for
2 mm Ø split pin
2 M10 / 1.5
Locknuts
and washer
Key to assembly
6
53
7
1
8
4
2
Fig. 18.3 (continued)
Draw your solution in first angle projection and add
the title and projection symbol in a suitable title block.
3 Cam operated clamp
Details of a cam operated clamp are shown in Fig.
18.3 together with a key showing the position of the
various components in the assembly. Draw the following
views in first angle projection:
(a) A front view taken as a section through the vertical
centre line of the clamp and generally as outlined
in the key.
(b) An end view projected on the right-hand side of
the front view
(c) A plan view drawn beneath the front view
Add to your solution a title, scale, projection symbol,
parts list and reference balloons.
4 Plug cock
Details of a plug cock are shown in Fig. 18.4. Draw
the following two views of the assembled plug cock:
(a) A view in half section showing the outside view
on the left of the vertical centre line and a section
on the right hand side, the position of the valve
body being similar to that shown on the given
detail.
(b) An outside end view
Add a title and a parts list. Hidden details are not
required in either view. Include on your assembly
suitable nuts and bolts and washers where applicable.
Between the valve body and cover include a joint ring
of thickness 2 mm. The gland should be positioned
entering 10 mm into the valve cover. First or third
angle projected views will be acceptable.
5 Air engine
The component parts of an oscillating air engine are
detailed in Fig. 18.5. Draw in first angle projection
and, at twice full size, the following views;
(a) A front view taken as a section through the engine
cylinder and flywheel.
(b) A plan view in projection with the front view and
drawn below the front view.
(c) An end view on the right hand side and in projection
with the front view.
Hidden detail is not required in any view. Add a
parts list to your drawing and reference balloons to
identify each of the components in the assembly.
Worked examples in machine drawing 141
Fig. 18.4
Drill 4 holes Ø 15
equally spaced off
centres on 120 P.C.D.
R16
φ
56
10
3
φ
100
φ
124
13
50
φ
66
φ
86
φ
98
25
50
52
14
14
φ
76
φ
150
R10
1
Valve body
100
140
105
210
50
70
Tap 4 Holes M12
× 1.5 × 16 deep
142 Manual of Engineering Drawing
16
10
10
L Hole
c
R37
R37
φ
32
φ
18
9
φ
36
28
78
3
10
60 53
Plug
2
2 holes
M12 × 1.5
55
21
14
3
φ
124
43
86
2 holes
Ø 13
4 holes Ø 4.5 on 70 P.C.D.
φ
97
42
A–A
100
50
R20
R16
A
50
100
4 Holes
φ
13
3
Valve body cover
A
φ
70
φ
55
5
Cover stud
M12 × 1.5
M12 × 1.5
2216
50
70
16
86 CRS
16
3
14
14
4 Gland
φ
55
φ
36
2821
65
6
Gland stud
M12 × 1.5
M12 × 1.5
φ
54
φ
63
25 square
(229)
Fig. 18.4 (continued)
Worked examples in machine drawing 143
5.0
2.0
90°
4 holes Ø 35
C’sk as shown
7.0
5
80
37.5
7.0
19.0
12.0
50.0
1
φ
15.0
φ
6.0
φ
40.0
3
45°
1.5
45°
1.5
10.0
30.0
M3 × 0.5
5
4
2
φ
6
80.0
5.0
M6 × 1
20.0
4.012.0
Tongue to be
brazed into
slot on item 1
5.0
22.0
φ
10.00 ream
4 holes M3 × 0.5
on 20.0 PCD
52.0
100.0
φ
2.0
φ
4.0
5.0
R13.0
φ
5.0
6.0
3.0
φ
13
4.0
42.0
φ
16
7
φ
2
M5 × 0.8
6
Sweat cylinder item 7
into hollow
1
17.0
R8
13.0
φ
2.0
4.0
17.0
16.0
5
8.0
M3 × 0.5
Fig. 18.5
144 Manual of Engineering Drawing
8
φ
13.0
45°
1.0
φ
16.0
2.0
4.0
φ
4.0
2.0
8.0
4
11
5.0
1.0
φ
10.0
φ
40.0
12
13.0
4.0
8.0
M4 × 0.7
M6 × 1.0
φ
10.00
9.97
φ
8
5.5
30
24.0
4 Holes M3 clear
13
20.0
6.0
6.0
20 PCD
φ
26.0
30.0
10
φ
8.0
6.0
φ
4.0
φ
5.0
35.0
5.0
M5 × 0.8
9
φ
12.96
12.93
M5 × 0.8
2.0
2.0
2.0
5.0
15.0
40.0
4.0
Connecting pipes 2 off 20 swg
sweat in ports
15
φ
8.0
6.00 Ream
5.01.5
φ
10.0
14
φ
15.0
φ
10.0
5.0
8.0
17
Med. knurl
M5 × 0.8
M5 × 0.8
φ
5.0
4.0
45.0
18
25.0
M5 × 0.8
16
Light steel compression
spring id 5.0
M4 × 0.7
Fig. 18.5 (continued)
Worked examples in machine drawing 145
6 Toolbox
The details in Fig. 18.6 show parts of a toolbox which
can be made as a sheet-metal-work exercise.
A development is given of the end plates (two
required) and these should be drilled at the corners
before bending, to avoid possible cracking taking place.
Note, from the photograph, that the ends have been
pressed with grooves to provide additional stiffening
and this can be done if facilities are available.
The bottom and sides are fabricated in one piece
and drillings are shown for pop rivets. Drill the end
plates using the sides as templates to take account of
deformation which may occur while bending the metal
plate.
Details are shown of the hinges and some clearance
must be provided for their satisfactory operation. Before
50
73
110
160
10
6
10
30
2 holes Ø 3
196
Part 1
End plates 2 req’d 1
mm MS
Drill Ø 2 holes at
each corner
before bending
Development of
end plate
After drilling, fold
along bend line to
this position
35°
Part 3
Box lid
2 req’d 1mm MS
350
42
42 33
424233
107
57
20
Bend line
6
136
22
8
175
6 at 45°
140
88
10
Bend line
10 Holes Ø 3
42
42
33
42
42
33
350
Bend line
310 20
8
35°
196 Inside
68 60
Ø 3 Holes fixings
to endplates
Pictorial view (scale 1 : 4)
showing folded sides to
internal radius of 2mm also
bottom holes for riveting to
endplates
Note: All corners may be cut
back 10mm to fit flush with
endplates
10
All holes Ø
3
Part 2
Bottom and side panels
1 req’d 1mm MS
12
45 45
111
6
80
10
Fig. 18.6
146 Manual of Engineering Drawing
348
50
10
Drill 2–Ø 3 holes
Each end on assembly
2
10
25
174
Part 4
Top support
1 req’d 1 mm MS
Assemble under end plates
by pop riveting
92
50
8
9
19
38
2525
25
100
Blank for hinge 8
req’d
Roll hinge blank
to suit MS rod
Ø 4 × 102 long
Peen over pin
at each end
40
30
325
Fold up four
sides. Weld
or braze
corners
Part 9
Handle clips
4 req’d 1mm MS
14
7
6
6
20
R7
2 Holes Ø 3
Part 8
Handle
2 req’d
150
100
25
R5
85
Ø 5 MS Rod R5
30
40
20
100
Part 10
Tool tray
1 req’d 1mm MS
Tool tray
development
Bend lines
12
1224
24
Ø 3 Hole
each end
196
Fold up both
ends. Weld or
braze corners
Part 11
Tray support bracket
2 req’d 1mm MS
Development
Part 7
Catch 2mm
MS 1 req’d
10
3
3
18
φ
10
R8
Roll hinge blank to suit
MS pin Ø 4 × 26 long
Peen over pin
at each end
Part 6
Hasp
1 req’d 1mm MS
20
29
12
8
10
26
3
55
R6
4
Part 5
Assembled hinge
4 req’d 1mm MS
14
14
8
15
2 holes Ø 3
8
10
30
6
14
26
R25
Fig. 18.6 (continued)
3 holes
Ø 3
Worked examples in machine drawing 147
drilling the sides and lids for the hinges using the
dimensions given, use the hinges as manufactured to
check the hole centres for the rivets. One lid must
overlap the other to close the box, so some adjustment
here may be required. On the toolbox illustrated, pop
rivets were used on the sides and roundhead rivets on
the lid. Roundhead rivets were also used to assemble
the handle clips. Check also the drill sizes for the
rivets used as alternatives are available.
The top support member was pop riveted to the end
plates after the catch had been welded on the underside.
The slot in each lid slips over this catch to allow a
padlock to secure the toolbox.
A tooltray may also be made if required and details
are provided. The tray supports also offer added stability
and were pop riveted on assembly.
Remove all sharp corners and edges before assembly
of each part. The completed toolbox can be stove
enamelled, painted or sprayed according to personal
choice.
As an additional exercise, copy the given details
and produce an assembly drawing complete with parts
list. Also, produce patterns to cut the components from
sheet metal economically. This example provides useful
practice in reading and applying engineering drawings.
Solution shown in Fig. 18.12 (and see Fig. 18.13).
Solution notes
Fig. 18.7 Bushed bearing bracket
Note that in the end view there is an example of a thin
web which is not cross hatched. The example shows
three examples of counterbored holes used to contain
heads of fixing screws.
A liner bush with an interference fit is also indicated,
and since the bush is relatively thin compared with the
main casting, its cross hatching lines are drawn closer
together.
Fig. 18.8 Drill table
The table is clamped to the drilling machine main
vertical pillar using two bolts. The slot permits
tightening.
Cross hatching is omitted on the left side of the
front view.
Fig. 18.9 Cam operated clamp
This example shows a typical assembly and includes a
parts list.
Fig. 18.7
A
B
B
A
A–A
B–B
Title
Bushed bearing bracket
First angle projection
Dimensions in millimetres Scale:
Drawn by: Approved by:
148 Manual of Engineering Drawing
The balloons containing the part numbers are equally
spaced whenever possible. The leader lines to the
components terminate in a dot. The leader line is also
directed towards the centre of the balloon and touches
the circumference.
It is considered good policy to position the parts list
and commence writing in such a way that parts can be
added on to the end of the list in the event of future
modifications. The list can be drawn at the top or bottom
of the drawing sheet.
Fig. 18.10 Plug cock assembly
This example illustrates a typical industrial valve. The
plug turns through 90° between the on and off positions.
Spanner flats are provided and indicated by the diagonal
lines. Gland packing (Part 10) is supplied in rings.
These rings are contained by the body cover and on
assembly are fed over the plug spindle. The gland is
tightened and the compressive force squeezes the
packing to provide a seal, sufficient to prevent leaks,
but enabling the spindle to be turned. The joint ring
(Part 9) is too thin to be cross hatched and is shown
filled in.
This is also an example of a symmetrical part where
the half section gives an outside view and a sectional
view to indicate the internal details.
Fig. 18.11 Air engine assembly,
illustrated below
The engine operates through compressed air entering
the cylinder via one of the connecting pipes shown as
item 15. The other pipe serves to exhaust the cylinder
after the power stroke. The cylinder oscillates in an
arc and a hole through the cylinder wall lines up with
the inlet and exhaust pipes at each 180° of rotation of
the flywheel.
The spindles (Parts 4 and 18), grub screw (Part 5)
and the pin (Part 11) would not normally be sectioned.
A part section is illustrated at the bottom of the
connecting rod in order to show its assembly with the
crank pin (Part 11). The BS convention is shown for
the spring (Part 16). The BS convention is also shown
for cross knurling on the nut (Part 17).
Note. If the solutions to examples 3, 4, 5, and 6 had
been required to be drawn in third angle projection,
then the views would have been arranged as shown in
Fig. 18.13.
Fig. 18.8
A–A
A A
Title
Drill table
First angle projection
Dimensions in millimetres Scale:
Drawn by: Approved by:
Worked examples in machine drawing 149
4
3
1
Half section A–A
A
6
8
7
10
9
7
8
5
2
Item Description No.
No. off
1 Valve body 1
2 Plug 1
3 Valve body cover 1
4 Gland 1
5 Cover stud 4
6 Gland stud 2
7 Washer 6
8 Nut 6
9 Joint ring 1
10 Gland packing 4
Title
Plug cock assembly
Projection First Projection
angle Symbol
Dimensions in millimetres Original scale 1:1
All unspecified radll 3 mm Drawn by
2
4
8
1
7
3
6
5
10
9
10
X
X–X
10 M10 washer 3
9 M10 locknut 2
8 Cam pivot 1
7 Arm pivot 1
6 Spring 1
5 Plunger 1
4 Stopscrew 1
3 Cam plate 1
2 Operating arm 1
1 Clamp base 1
Part
Description
N° off
N°
Title
Assembly of cam
operated clamp
First angle projection
Dimensions in millimetres Scale:
Drawn by: Approved by:
Fig. 18.9
Fig. 18.10
X