Downloaded from https://www.everyspec.com -A 600 + .00I r1*.200+002 I 000DIA. HOLE -1.150 +.002 SECTION THROUGH A-A Oture 5-29. Correct statement of reqWreomeus for small hole that sharp corners hall be broken, the inspector checks the dimension in the direction of min- cannot check this dimension directly. The gage imum metal conditions. All gage tolerances are engineer will convert the roquirements to the da- within the component tolerance, and in effect turn method of dimensioning tapers when desig- the total amount of the gage tolerances repre- nating a gage for such a part.
The design en- sent& a proportion of the component tolerance gineer should also use the datum method wher- which is denied the contractor. in addition, ever possible. If sharp corners are required, since parts must enter or be entered by the GO the note "sharp corners required" should be gage to be acceptable, their constant use pro- added to the drawing. duces wear on the gaging surfaces. To reduce the expense of frequent replacement of gages, 5-28. Effect of Gage Tolerance on Component and to ensure that parts will not exceed the Tolerance.
When specifying tolerances on di- maximum permissible metal conditions, a wear mensions, the design engineer must be aware of allowance, also within the component tolerance, the effect of gage toleranceb ois the component is applied to the GO gage prior to the applica- tolerances. tion of the gage tolerance. Although gages are produced by methods that Figure 5-29a shows a simple cylindrical part permit closer tolerances than are possible with dimensioned diametrically, the shaded areas mass-produced components, there is still atol- indicating schematically the tolerance zone per- erance which must be allowed tothe gage maker. mitted by the drawing.
Figure 5-29b shows an And since the usual type of dimensional gaging enlargement of figure 5-29a, in which there are requires two gaMes, GO and NOT GO, the gage indicated schematically the effects ai Ordnance tolerances are compounded. The GO gage acceptance gage tolerance and work gage tol- checks the dimension in the direction of max- erances on the tolerance zone permitted by the imum metal conditions, while the NOT GO gage drawing. It will be noted that there is no wear 5-24