The pencil is used to draw a variety of lines, divided into soft, hard two kinds. Pencil labeled "B" that the soft lead, the larger the number in front of the B, that the lead is softer, the blacker the drawing line; pencil labeled "H" that the hard lead, the larger the number in front of the H, that the lead is harder, the lighter the drawing line. The pencil labeled HB is moderately soft and hard. H pencils are good for underlining, B pencils are good for underlining and solid lines, and HB pencils are good for underlining. Of course, you can also choose according to your own situation. Drawing fine solid lines, dotted lines, dotted lines and other fine lines used in pencil grade H or 2H, the lead will be repaired into a conical core, as shown in the figure. When the lead core is worn bald, it should be repaired in time, do not make do with the drawing. Drawing dotted lines and dotted lines, beginners should count the number of millimeters on the ruler or triangle board, so that after a period of practice, the dotted line or dotted line drawn line length can be neat and equal. Drawing a thick solid line round the lead core used for HB lead core, thick solid line is the most important line in the drawing, in order to draw a thick solid line of uniformity and neatness, the key is the correct repair and use of pencils, drawing a thick solid line of pencils to HB or B pencils are appropriate. Repair the lead core into a rectangular shape, use the rectangular short prongs and paper contact, rectangular lead core of the broad side and the ruler or triangle guiding prongs tightly, the force should be uniform, slow, once a drawing is not black can repeat the pen
1, engineering drawing (technical drawing), is the creation of a standardized engineering drawings (also referred to as technical drawings) of the technology. Experts in this skill are called "cartographers". Today, most of the mechanics of the drafting task is automated and greatly accelerated by the use of computer-aided design (CAD) systems, but the task of controlling the revision of engineering drawings is still non-automated.
2, engineering drawing tools: drawing boards and butyl rulers, triangular boards, scales, minute rulers, circular rulers, pencils, duckbill pens, curve boards
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