Fig Hole Patterns Of Fig Two Singlesegment Feature Control Frames With Secondary Datum In Lower Feature Control Frame

pattern, and Fig. 5-20(f) for the six-hole pattern of features shown in Fig. 5-20. Two Single-Segment Feature Control Frames. Where it is desired to invoke basic dimensions along with the datum references, single-segment feature control frames are used. See Fig. 3-22(b). Figure 5-21 shows two single-segment feature control frames. The lower feature control frame repeats datums A and B. Figure 5-21(c) shows that the tolerance cylinders of the FRTZF (as a group) are free to be displaced to the left or right as governed by the basically-located tolerance cylinders of the PLTZF, while remaining perpendicular to datum plane A and parallel to datum plane B. Figure 5-21(d) shows that the actual axes of the holes in the actual feature pattern must reside within both the tolerance cylinders of the FRTZF and the PLTZF. Figure 5-21 (e) repeats the heretofore-described relationships for the four-hole pattern, and Fig. 5-2l(f) for the six-hole pattern of features shown in Fig. 5-21. In Terms of Hole Surfaces. Figures 5-19(g) through (i) illustrate the same three-hole pattern of Figs. 5-19(a) through (d), explained in terms of hole surfaces relative to acceptance boundaries. See para. By comparing Fig. 5-19(d) with Fig. 5-19(i), it can be seen that the result is the same for both axis and surface explanations except as noted in para.

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