IS 11166 : 1993 Permissible deviations on dimensions, surface roughness and mass of steel castings made with investment casting process

1 Scope

1.1 This standard covers the permissible deviations ondimensions, surface roughness and mass of steel castings made withinvestment casting process. This standard provides for thefollowing two classes of permissible deviations.

Class 1 - Involving a closer control over the process and inmost cases, a higher cost of manufacture

Class 2 - Involving normal controls and in most cases a lowercost of manufacture

1.2 Normally on the engineering drawing, tolerances shall bespecified on all important dimensions, on surface roughness atimportant areas and on mass of those castings where the mass is arelevant factor, The tolerances thus specified shall normally be inconformity with the values specified against Class 1 and Class 2.

1.3 With exceptionally close control or with certain additionaloperations, it may be possible to achieve a level of control closerthan Class 1 also. The designer may call for such a closer level oftolerances on especially critical dimensions, but it is recommendedthat this be done in consultation with the manufacturer.

1.4 Unless otherwise specified on the drawing or in the enquiryand order, on the untoleranced dimensions, surface roughness andmass, the deviations mentioned against Class 2 shall apply.