Page 145 - CITS - ED - Mechanical

ENGINEERING DRAWING - CITS

Procedure

Screw threads
Exercise8.1
Draw the basic profile of ISO metric external thread M30. (Fig 1)

Fig 1

Pitch M30 = 3.5 mm

P = 3.50 mm P/8 = 0.4375 mm
P/4 = 0.8750 mm H = 3.0311 mm
H/8 = 0.3789 H/4 = 0.758 mm
Since the above mensioned sizes are very small, we can take suitable enlarged scale.

We can take 10:1 scale and draw the external ISO metric thread as shown in Figure 1.
In 10:1 scale approximate values of different dimensions.
P = 35 mm P/8 = 4.5 mm P/4 = 9 mm
H = 30 mm H/8 = 4 mm H/4 = 8 mm

Exercise 8.2
Follow the procedure of Ex.15.1 and complete the drawing of Iso-metric internal thread. (Fig 2)

Fig 2

Exercise 8.3
Draw the profile of 1" BSW external thread. (Fig 3)

132
CITS :Engineering Drawing (Mechanical) - Exercise 8