Bold Lines (soft B to 2B pencil lead in a .5mm or .7mm mechanical pencil)
The primary objects in a drawing should be created using a bold line. Bold lines are very dark and have a thick width. These are created with a .5mm or .7mm mechanical pencil and a soft B to 2B pencil lead. Walls in plan view and the outline around the perimeter of an elevation or three-dimensional object are examples where bold lines should be used.
Medium Lines (HB pencil lead in a .5mm mechanical pencil)
Secondary objects such as doors, furnishings, counters, and cabinets should be drawn in a medium line weight. In elevation and 3D views, the perimeter of an object may be drawn in a bold line weight however the information inside the object should be drawn in a medium weight. Medium line weights are best created using a .5 mm width pencil with HB pencil lead.
Light Lines (H to 2H pencil lead in a .3mm or .5mm)
Action lines, information lines, and fill patterns should be drawn with light lines. Action lines show potential movement of an object and include door swings in plan view and hinge direction in elevation view. Information lines convey information about a drawing and include dimension lines, center lines, leader lines, sections lines, and so on. Fill patterns are specific symbols used to indicate a type of material being used. The light lines can be created with a .5 mm pencil or with a .3 mm pencil and H to 2H pencil leads. It is very important that all of these lines are visible, so do not confuse the term “light” with “hard to see.”
Border Lines (2B to 4B pencil lead in a .7mm or .9mm pencil)
Border lines are used to create a margin on the drawing sheet and to create the lines around the title block. Border lines should be as dark and about twice as thick as bold lines. A .7 mm or .9 mm pencil with a 2B to 4B lead works well for creating borderlines.