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GENERAL All individual tolerances apply to each and every forged part unless specifically noted otherwise. Tolerances as stated in all tables are considered for use by final inspection departments at the forge plant and/or by receiving or source inspection by the purchaser. PRINTS AND SPECIFICATIONS It is important that forging drawings be accurate and complete. The purchaser should indicate his first operation locating points, normally as a part of the drawing, and give prior notice should these points be changed. It is equally important that the purchaser provide drawings of the finish machined part, or equivalent information. This will assist in the design of forging dies and tools, and in establishing most effective final inspection procedures. Unless the purchaser's drawings and specifications direct otherwise, all dimensions are normally assumed to refer to lines intersecting at right angles to each other (commonly referred to as X,, Y, and Z axes). Furthermore, unless the purchaser's drawings or specifications direct otherwise, circular shapes are normally assumed to be figures of revolution with a center on an axis, and all circular dimensions are normally shown as diameters. DIMENSIONAL PRACTICES FOR FORGING DRAWINGS At the time of first printing of this publication, a transition period existed dealing with the conversion from the customary decimal inch system to dimensioning to the metric system. The following procedures will apply concerning dimensioning on forging drawings: (1) Metric System _ metric dimensions, on forging drawings, will be extended to one place decimal millimeter for both part dimensions and tolerances (0.1); and (2) Decimal Inch System _ inch units of measure on forging drawings will be extended to two place decimals for both dimensions and tolerances (0.01).
UNITS
AND METHODS OF MEASURE
METHOD The forgeman must do much of his measuring (hot inspection) of forgings while they are hot, using practical forge shop instruments such as calipers, rule, straight edge and profile template. The precision of his measurements is therefore limited by the characteristics of such instruments and the conditions under which they must be used.
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