tailieunhanh - Dimensioning and Tolerancing Part 2

Tham khảo tài liệu 'dimensioning and tolerancing part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | AS NE DIMENSIONING AND TOLERANCING dial relative to the arc. Where the radius dimension line is foreshortened and the center is located by cooidinate dimensions the dimension line locating the center is also foreshortened. True Radius. Where a radius is dimensioned in a view that does not show the true shape of the radius TRUE R is added before the radius dimension. See Fig. 1-24. Multiple Radii. Where a part has a number of radii of the same dimension a note may be used instead of dimensioning each radius separately. Spherical Radii. Where a spherical surface is dimensioned by a radius the radius dimension is preceded by the symbol SR. See Fig. 1-25. Chords Arcs and Angles. The dimensioning of chords arcs and angles shall be as shown in Fig. 1-26. Rounded Ends. Overall dimensions are used for features having rounded ends. For fully rounded ends the radii are indicated but not dimen- FIG. 1-26 DIMENSIONING CHORDS. ARCS. AND ANGLES sioned. See Fig. 1-27. For features with partially rounded ends the radii are dimensioned. See Fig. 1-28. Rounded Comers. Where comers are rounded dimensions define the edges and the arcs are tangent. See Fig. 1-29. Outlines Consisting of Arcs. A curved outline composed of two or more arcs is dimensioned by giving the radii of all arcs and locating the necessary centers with coordinate dimensions. Other radii are located on the basis of their points of tangency. See Fig. 1-30. Irregular Outlines. Irregular outlines may be dimensioned as shown in Figs. 1-31 and 1-32. Circular or noncircular outlines may be dimensioned by the rectangular coordinate or offset method. See 12 DIMENSIONING AND TOLERANCING ASME FIG. 1-31 COORDINATE OR OFFSET OUTLINE STATION 1 2 3 4 5 X 2 5 15 27 55 Y 15 FIG. 1-32 TABULATED OUTLINE Fig. 1-31. Coordinates are dimensioned from base lines. Where many coordinates are required to define an outline the vertical and .