Machine Drawing

Surface Roughness 249

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d:\N-Design\Des16-1.pm5

Fig. 16.7

a

All over

a

Fig. 16.8

a 3

a 2

a 3

a 2

(a) (b)

a 3

a 2

(c)

a

All over

except where

otherwise stated

a 1 a 1 a 2 a 3

Fig. 16.9

To avoid the necessity of repeating a complicated specification a number of times, or

where space is limited, a simplified specification may be used on the surface, provided that its

meaning is explained near the drawing of the part, near the title block or in the space devoted

to general notes (Fig. 16.10).