Page 74 - Personal Study Notes (Engineering Metrology - 22342)

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Q. Explain Indian standard (IS 919 – 1963).

1. The Indian standard system of limits and fits comprises suitable combination of 18
grades of fundamental tolerances or grades of accuracy of manufacturer (IT0 to IT16),
and 25 types of fundamental deviations represented by letter symbols for both holes
and shafts (capital letters A to ZC for holes and lower case letters a to zc for shafts).

2. In diameter steps up to 500mm.

3. The 25 fundamental deviations of hole are represented BY

A,B,C,D,E,F,G,H,JS,J,K,M,N,P,R,S,T,U,V,X,Y,Z,ZA,ZB,ZC.

For more details,

http://www.questin.org/sites/default/files/standards/is.919.1.1993.pdf

Engineering Metrology (Only For Personal Use) 31