Pencils are used to draw all kinds of lines, soft and hard. The pen marked with "B" indicates soft lead, and the larger the number before B indicates that the lead is softer and the deeper the line is drawn; The pen body marked with "H" indicates a hard lead, and the larger the number in front of H indicates that the lead is harder and the drawing line will be shallower. The pencil marked HB has moderate hardness. ? H pencil is suitable for drawing lines, B pencil is suitable for drawing lines and thick solid lines, and HB pencil is suitable for drawing lines. Of course, you can also choose according to your own situation. The pencil used to draw thin lines such as solid lines, dotted lines and dotted lines is H or 2H, and the lead is tapered, as shown in the figure. If the lead core is bald, it should be repaired in time. Don't make do with painting. When beginners draw dotted lines and dotted lines, they should count a few millimeters on the T-square or triangle, so that after a period of practice, the line segments of dotted lines or dotted lines can be neat and equal. The lead used to draw the thick solid line circle is HB lead, and the thick solid line is the most important drawing line in the pattern. In order to draw a uniform and neat thick solid line, the key is to repair and use the pencil correctly. The pencil for drawing a thick solid line is HB or B, and the lead is trimmed into a rectangle. When in use, touch the paper with the short side of the rectangle. The wide edge of the rectangular lead is closely attached to the leading edge of the T-shaped square or triangular plate. The force should be even and slow. If the drawing is not black at one time, you can carry the pen repeatedly.
1, technical drawing, is the technology to create standardized engineering drawings (also known as technical drawing). Experts in this field are called "cartographers". Today, the mechanism of drawing task is mostly automatic, and the drawing task has been greatly accelerated by using computer aided design (CAD) system, but the revision control task of engineering drawing is still non-automatic.
2. Engineering drawing tools: sketchpad and T-square, triangle, scale, compass, compass, pencil, duckbill pen and curved board.
reference data
Sogou's question and answer: /v64784409.htm? From the title =% E5% B7% A5% E7% A8% 8B% E5% 88% B6% E5% 9B% Be