... dimensioning a part. Figure 4- 4 shows a part with four holes. The designer selected the back of the part as the primarydatum, datum A, because the back of the part mates with another part, and the ... PBUMHBD031- 04 MHBD031-Cogorno-v6.cls April 10, 2006 20:8Datums 59Figure 4- 13 Fixture for the part shown in Fig. 4- 14. Datum TargetsSome manufacturing processes, such as casting, forging, welding, and ... B2BDatumTargetLineDatumTargetPointFigure 4- 14 A part with datum target areas, target points, and a target line.A2, and A3. All datum targets are dimensioned for location and size either bytoleranced dimensions...