Figure 3-31.-Breaking extension lines and leaders at points of intersection. Sections are used to show interior details clearly. Sectional views reveal hidden details in a mechanical drawing. PRECEDENCE OF LINE Visible line Order of importance Hidden line Center line Engineering Drawing www.AgriMoon.Com 24. radius of an arc is to be indicated, there is an arrow at only the end of the line that touches the arc. Cross hatching in the section view shows the solid surface of the object which were cut through to produce the section. ... mechanical engineering drawings; a slash, or a dot in architecture. cutting plane is a frontal plane and appears as a line in the top view. The other end, without an arrow, terminates at the point used as the center in drawing the arc. • If possible, dimension lines are aligned and grouped for uniform appearance. The surface of the imaginary cut is crosshatched with lines called section lines. section line is drawn at a 45-degree angle and spaced 1.5 mm to 3 mm or more, depending on the size of the drawing. HIDDEN LINE PRACTICE Hidden line should join a visible line, except it extended from the visible line. The section line defines the extents of the section to extract from the building model. Correct Join The section lines should be evenly spaced and of equal thickness, and should be thinner than visible lines Sectional views are used in engineering and architectural drawings. Note: In SolidWorks, inserted dimensions in the drawing are displayed in gray. – Section lines/crosshatch lines . Section lines are bidirectional and you can specify the length and depth of the section line either visually, using the pointing device, or by entering numeric values. SECTIONING IN ENGG DRAWING 1. The first step in creating a section is to draw a section line through the building model. Drafting - Drafting - Hidden lines: It is standard practice to use dashes to represent any line of an object that is hidden from view. The arrows at the ends of cutting-plane line point in the direction of sight for front section. According to DoD-STD-100C, “section lining shall be composed of uniformly spaced lines at an angle of 45 degrees to the baseline of the section. SECTIONING 2. Section Line Engineering Drawing www.AgriMoon.Com 23. The arrowhead on a dimension or leader line is an important detail of a drawing. Section Line. Imported dimensions from the part are displayed in black. A cutting-plane line shows where object was cut to obtain the section view. Since they are used to set off a section, they must be drawn with care. These views assume that a cutting plane has removed portions of the object represented by the drawing, displaying the appropriate section of the interior. Section lines are very light. A section line is a .7 mm to .9 mm line drawn at angles, normally 45, 30 or 60 degrees, to show a feature more clearly. As a general rule, use 3mm spacing. Section lines are drawn as thin (.35 mm) black lines, using an H or 2H pencil. On adjacent parts, the lines shall be drawn in opposite directions. When sketching an object or part that requires a sectional view, they are drawn by eye at an angle of approximately 45 degrees, and are spaced about 1/8” apart. It is best to use the symbol for the material being shown as a section on a sketch. Break lines would be used to eliminate the section between the threaded sections to shorten the object. 7-4 Interpreting Cutting Planes and Sections The result is called a front section, or front view in section, since it replaces the front view in the drawing.
2020 section line in engineering drawing