254 Machine Drawing
dharm
d:\N-Design\Des17-1.pm5
11. What is the slope of the recess in the housing base?
—15°
12. What are the other dimensions of the recess?
—57mm × 12.5mm × 38mm
13. What is the width and thickness of the base?
—63mm × 16mm
14. What is the width of the rib marked ‘X’?
—25 mm
17.2.3 Gear Box Cover
Study the two orthographic views and the local sections of the gear box cover shown in Fig. 17.3
and answer the following :
1. How is the cover fixed to the gear box?
— By means of 6 screws
2. What is the size of the thread?
—M 10
3. What is the thread size ‘A’ shown in the view from the front?
—M 20
4. What are the values of the dimensions B, C, D and E in the view from the front?
—B = φ 21, C = φ 18, D = 6 mm, and E = 34 mm
5. What is the thickness of the cover at section B-B?
—6 mm
6. What will be the gasket size, if required?
—262mm × 124mm
7. How many tapped holes are there on the side opening of the cover and what is the
size?
—4, M 6
8. What is the material and method of manufacture suggested for the cover?
—Cast iron, CO 2 sand casting
9. What are the dimensions of F, G and H marked in the view from above.
—F = 24 mm, G = R 9 and H = R 10
10. What is the maximum height of the cover?
—90 mm
11. What is the wall thickness of the cover and the fillet radius where no size is men-
tioned?
—Thickness = 6 mm, fillet radius = 3 mm
17.2.4 Steam Stop Valve
A steam stop valve is mounted on the steam pipe, close to the engine to regulate the flow of
steam through pipes and shut-off completely when not required. It is operated by means of a
hand wheel. These valves have a low lift and hence can be closed and opened quickly.
Figure 17.4 shows the sectional view of an assembly drawing of a steam stop valve. The
hand wheel (5) which operates the valve (2) is fitted on to the spindle (4). The spindle is screwed
into the bush (6) which is fixed to the bridge (7) by two countersunk screws (8). The bridge is
