TED tHe LaNGuAgE oF LiNeS 9/15/2023

Object Line

A thick continuous line, used to outline the visible edges or contours of an object.

Hidden Line

A medium weight line, made of short dashes about 1/8” long with 1/16” gaps, to show edges, surfaces and corners which cannot be seen. Sometimes they are used to make a drawing easier to understand.

Center Line

Used to indicate the centers of holes, arcs, and symmetrical objects. They are very thin, long-short-long lines.

Dimension Line

Thin and are used to show the actual size of an object. There are arrowheads at both ends that terminate at the extension lines.

Extension Line

Thin lines, showing the limits of dimensions. Dimension line arrowheads touch these lines. They are kept 1/16” from the part so they cannot be confused with an object line.

Leader Line

Thin line used to dimension circles or arcs or to point to an area of a drawing requiring a note for explanation. They are preferably drawn at 45° angles.

Cutting Plane Line

Helps to show the internal shape at a part or assembly by slicing through the object. (very heavy)

Section Line

Used to show the interior details of an object as if it had been cut. They are fine, dark lines. Various types of section lines may indicate the type of material cut by the cutting plane line. Section lines that are diagonal and parallel are called “Hatching”

Break Line

There are three different kinds of lines. They are used to remove, or ‘break out” part of a drawing for clarity, and also to shorten objects which have the same shape throughout their length and may be too long to place on the drawing. Short and long lines are used for flat surfaces. Cylindrical are used on rods, dowels, etc.

Phantom line

Long-short-short-long lines most often used to show the travel or movement of an object or a part in alternate positions. It can also be used to show adjacent objects or features.