Machine Drawing

Limits, Tolerances and Fits 235

dharm
d:\N-Design\Des15-2.pm5

a – Correct b – Correct c – Incorrect

d – Correct e – Correct

Fig. 15.18 Indication of feature controlled (outline or surface only)

15.5.9 Standards Followed in Industry

Comparison of systems of indication of tolerances of form and of position as per IS: 3000

(part-1)-1976 and as prevalent in industry are shown in Table 15.8.

Table 15.8 Systems of indication of tolerances of form and of position

As per the standard As prevalent in industry

1. Straightness tolerance
   
   
   • f0.08
   
   
   
   

Permissible

unstraightness 0.08

2. Flatness tolerance

0.08

Permissible

unevenness 0.08

3. Circularity tolerance

O 0.1

Permissible

ovality 0.2

(Contd.)