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Dimensioning and Tolerancing Part 10

Tham khảo tài liệu 'dimensioning and tolerancing part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | DIMENSIONING AND TOLERANCING ASME Y14.6M-1994 meat of clearance holes to provide for an extreme variation in perpendicularity of the fastener is not necessary. 5.5.2 Application. Figures 5-33 and 5-34 illustrate the application of a positional tolerance using a projected tolerance zone. The specified value for the projected tolerance zone is a minimum and represents the maximum permissible mating part thickness or the maximum installed length or height of the components such as screws studs or dowel pins. See para. 5.5.3. The dữection and height of the projected tolerance zone are indicated as illusữated. The minimum extent and direction of the projected tolerance zone are shown in a drawing view as a dimensioned value with a heavy chain line drawn closely adjacent to an extension of the center line of the hole. 5.5.3 Stud and Pin Application. Where studs or press-fit pins are located on an assembly drawing the specified positional tolerance applies only to the height of the projecting portion of the stud or pin after installation and the specification of a projected tolerance zone is unnecessary. However a projected tolerance zone is applicable where threaded or plain holes for studs or pins are located on a detail part drawing. Tn these cases the specified projected height should equal the maximum permissible height of the stud or pin after installation not the mating part thickness. See Fig. 5-35. 5.6 NONPARALLEL HOLES Positional tolerancing lends itself to patterns of holes where axes are not parallel to each other and where axes are not normal to the surface. See Fig. 5-36. 5.7 COUNTERBORED HOLES Where positional tolerances are used to locate coaxial features such as counterbored holes the following practices apply. a Where the same positional tolerance is used to locate both holes and counterbores a single feature cor.trol frame is placed under the callouts specifying hole and counterbore requừements. See Fig. 5-37. Identical diameter tolerance zones for hole