Fig Limited Length Or Area Indication

or area of a surface is to receive additional treatment or consideration within limits specified on the drawing. the extent of these limits may be indicated by use of a chain line. See Fig. 1-11. Chain Lines. In an appropriate view or section, a chain line is drawn parallel to the surface profile at a short distance from it. Dimensions are added for length and location. If applied to a surface of revolution, the indication may be shown on one side only. See Fig. 1-11(a). Omitting Chain Line Dimensions. If the chain line clearly indicates the location and extent of the surface area, dimensions may be omitted. See Fig. l-l 1(b). Area Indication Identification.

Where the desired area is shown on a direct view of the surface, the area is section lined within the chain line boundary and appropriately dimensioned. See Fig. 1-11(c).

1.7.4 Leaders (Leader Lines). A leader is used to direct a dimension, note, or symbol to the intended place on the drawing. Normally, a leader terminates in an arrowhead. However, where it is intended for a leader to refer to a surface by ending within the outline of that surface, the leader should terminate in a dot. A leader should be an inclined straight line except for a short horizontal portion extending to the mid-height of the first or last letter or digit of the note or dimension. Two or more leaders to adjacent areas on the drawing should be drawn parallel to each other. See Fig. I-12. Leader Directed Dimensions.

Leader directed dimensions are specified individually to avoid complicated leaders. See Fig. 1-13. If too many leaders would impair the legibility of the drawing, letters or symbols should be used to identify features. See Fig. 1-14. Circle and Arc. Where a leader is directed to a circle or an arc, its direction should be radial. See Fig. 1-15.

1.7.5 Reading Direction. Reading direction for the following specifications apply:

Third Angle Projection Symbol Dimensions

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