Loaf t>r*ak lint Short break line
(4) Extension Line. lines of the outline. the view outline.
Extension lines, very light in weight, are extended from They are started about one-sixteenth of an inch away from
(5) Dimension Line. Size is indicated on drawings by dimensions. Size dimensions are placed in a break in the dimension line. Some dimensions are placed between arrowhead tipped lines. In either case, the dimension distance is from the point of one arrowhead to the point of the other arrowhead. Normally, to keep dimensions clear, they are placed outside the view; sometimes, out of necessity, they are placed inside.
(6) Leader Line. Leaders are used as connectors between names and the proper lines they represent, to avoid confusion. The pointing end of the leader is usually tipped by an arrow. The note or name used with the leader is located in a clear space that is not covered by the views or dimension lines of the drawing.
(7) Phantom Line. These lines show possible alternate positions of moving parts. They are composed of alternating one long and two short dashes evenly spaced with a long dash at each end.
They are the same weight as hidden lines but are about twice as long.
(8) Cutting Plane Line. These lines indicate an imaginary cut, and arrows are used to show the direction the workman is to look at the sectional view.
(9) Long Break Line. These are space savers for the draftsman. They do not change the actual length indicated by the dimension, but make it possible for the draftsman to show an object for which he would not otherwise have room.
(10) Short Break Line. These are used to indicate that the draftsman has removed part of an outer surface to reveal the inside structure. They usually come in pairs.
b. Sections. A sectional view allows you to look inside an object shown on a shop drawing. Sectional views are necessary for a clear understanding of complicated parts. On simple drawings, a section may serve the purpose of an additional view.
(1) Full Section, (figure 79 on the following page). The object is cut completely through, showing the whole view in section.
(2) Offset Section, (figure 80 on the following page). A joggle or offset is in the cutting plane.
(3) Half Section, (figure 81 on page 91) . Two cutting planes meet at right angles at the center line.
(4) Revolved Section, (figure 82 on page 91) . This is a drawing within a drawing, which eliminates extra views of rolled shapes, ribs, etc.
(5) Removed Section, (figure 83 on page 92). This serves the same purpose as the revolved section, but instead of being drawn on the view, it is set off or shifted to some adjacent place on the paper. It may be enlarged to facilitate detailing and dimensioning.
(6) Broken-out Section, (figure 84 on page 92). This is done by removing a part of the outside surface when only a small area of the inside need be shown.
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