Downloaded from https://www.everyspec.com corresponding tolerance zone permitted by this tolerance area 0.002 in diameter, within vhich gage is shown by the circle inscribed in the the actual center of the hole may vary when square, and the dark shaded areas of the square produced to minimum size. Since there are an indicate the extent of the permissible tolerance infinite number of circles, representing the zone that will be denied the manufacturer.
minimum hole, with centers located on the tol- erance circle, representing maximum permis- On the other hand, a gage to permit the manu- sible locational variation, the pin of the gage will facturer the full tolerance expressed on the be made to a size equal to the minimum dia- d-awing would necessarily contain a round pin meter of the hole-minus the locational tolerance of th' .iize indicattd by the dotted circle.
The •.0 The difficulties encountered when tol- cerrebonding tolerance zone will be that circle eranced coordinates were used have been over- in which the square Is inscribed, and the light come; the manufacturer has his full tolerance, shaded areas indicate the extent to which parts and the gage will accept only conforming parts. ,mt of tolerance limits will be accepted by the gage.
Figure 5-20 gives a graphic explanation of why the gage will accept the maximum hole even The same part, dimensioned with a dependent when the tolerance circle is increased by the locational tolerance, is shown in figure 5-19a, amount of the tolerance on the dian- eter of the and the explanation of it in figure 5-19b. hole. The intersection of the basic coordinates, the In the sketches, shown enlarged in the figure, dimensions of which are theoretically exact, the circular shaded area is the pin. The solid locates the theoretically exact center of the hole.
and dashed circles represent the extreme posi- Since nothing can be produced to exact dlmen- tions of the hole in which the gage pin will en- sions, the small circle represents the locational ter, the correpoonding centerlines being-shown W0 .500+5003 00 K--1------4- S5009 BM 0 •Wur , -19. Dependent locat.i t.lerance L~- 18 - -______.--- ---- =-O0