IMPORTANT POINTS IN ENGINEERING DRAWING P-1
1. Best
pencils for lettering on most surfaces are the H, F, and HB grades.
2. Hold
your pencil approximately a 60 degree angle with the paper.
3. Pencils
used for Technical Drawing are 9H, 8H, 7H, 6H, 5H, and 4H. (Hard Lead)
4. Pencils
used for Free hand drawing and general layout
are 3H, 2H, H, F, HB, and B. (Medium Hard Lead)
5. Pencils
used for Free Hand Drawings are 2B, 3B, 4B, 5B, 6B, and 7B. (Soft Lead)
6. Range
of nominal height of Letters are 2.5 mm, 3.5 mm, 5 mm, 7 mm, 10 mm, 14 mm and 20 mm.
7. Vertical
Letters – 90 degrees to Horizontal.
8. Inclined
Letters – 75 Degrees to Horizontal.
9. Most
Free Hand letterings are done in a “Gothic” (with constant line thickness)
style.
10. Lettering type ‘A’ (d=h/14)
a. Lettering
Height (h) = (14/14) h
b. Height
of lower case Lettering (c) = (10/14) h
c. Spacing
between Characters (a) = (2/14) h
d. Min.
spacing of base characters (b) = (20/14) h
e. Min.
spacing between words (e) = (6/14) h
f. Thickness
of line (d) = (1/14) h
11. Lettering type ‘B’ (d=h/10)
a. Lettering
Height (h) = (10/10) h
b. Height
of lower case Lettering (c) = (7/10) h
c. Spacing
between Characters (a) = (2/10) h
d. Min.
spacing of base characters (b) = (14/10) h
e. Min.
spacing between words (e) = (6/10) h
f. Thickness
of line (d) = (1/10) h
12. For
details of lettering reference shall be made to IS: 9609 (Part I) - 1983.
13. ISO:
216-2007 Defining A & B series of paper sizes.
14. ISO:
269-1985 Defining C series for envelopes.
15. ISO:
217-2003 Defining the RA and SRA series of raw (untrimmed) paper Sizes.
16. ISO:
216, ISO: 269 and ISO: 217 standard papers have same aspect ratio i.e., 1:√2
(Except some Envelops).
17. The
lengths of ISO ‘C’ series papers are 9% larger than ISO ‘A’ series papers.
Tolerance
Tolerance
18. The
tolerances specified in the standards regarding drawing paper sizes are
a. ±
1.5 mm for dimensions up to 150 mm.
b. ±
2.0 mm for dimensions in the range of 150 mm to 600 mm.
c. ±
3.0 mm for dimensions above 600 mm.
19. These
are related to comparison between series A, B and C.
20. As
per IS: 11665-2010 DATA FIELDS IN TITLE BLOCKS AND DOCUMENT HEADERS, “the total width is 180 mm to fit an A4
sheet, with left margin being 20 mm and the right margin 10 mm. the same title
block is used for all paper sizes.”
21. Borders
and Frames.
22. The
Min. width of the borders for A0 and A1 drawing sheets is
20 mm.
23. The
Min. width of the borders for A2, A3 and A4
drawing sheets is 10 mm.
24. Metric
reference graduation with a min. length of 100 mm and divided in to 10 intervals
on all drawing sheets with a min. width of 5 mm near the frame at the border.
Grid
Reference system (Zoning):
26. It
is recommended that the length any side of grid should not less than 25 mm and
more than 75 mm.
Scales:
a. Full
size scale Ã
1 : 1
b. Enlarged
scale Ã
X : 1
c. Reduced
scale Ã
1 : X
28. Please
refer IS: 10714 (Part – 20) - 2001
“BASIC CONVENTIONS FOR LINES” For types of lines and their applications.
29. Thickness
of Lines:
30. All
lines shall be dense, clean and black to produce good prints. For details
reference shall be made to IS:
10714-1983.
31. The
Ratio of Thick to thin line should not be less than 2:1.
32. The
ranges of thickness of lines are 0.18, 0.25, 0.35, 0.5, 0.7, 1.0, 1.4, 2.0 mm.
33. In
accordance with IS 10164, the space between parallel lines (including hatching)
shall not be less than twice the thickness of the heaviest of these lines, with
a minimum spacing of 0.7 mm.
34. The
minimum spacing between adjacent flow lines and between flow lines and other
lines should be 10 mm.
35. NOTE
2 owing to difficulties in certain methods of reproduction, the line thickness
of .0.18 mm should be avoided.
Post a Comment