Manual Of Engineering Drawing British And International Standards

[Bran Cardello]

Manualof Engineering Drawing: British and International Standards, Fifth Edition, chronicles ISO and British Standards in engineering drawings, providing many examples that will help readers understand how to translate engineering specifications into a visual medium. The book includes 6 introductory chapters which provide foundational theory and contextual information regarding the broader context of engineering drawing and design. The concepts enclosed will help readers gain the most out of their drawing skills. As the standards referred to in this book change every few years, this new edition presents an important update.

1. Design office management and organization2. Product development and computer aided design3. Design for manufacture to end of life4. Intellectual property and engineering design5. CAD organization and applications6. Principles of first and third angle orthographic projection7. Linework and lettering8. Three-dimensional illustrations using isometric and oblique projection9. Drawing layouts and simplified methods10. Sections and sectional views11. Geometrical constructions and tangency12. Loci applications13. True lengths and auxiliary views14. Conic sections and interpenetration of solids15. Development of patterns from sheet materials16. Dimensioning principles17. Screw threads and conventional representations18. Nuts, bolts, screws, and washers19. Keys and key ways20. Worked examples in machine drawing21. Limits and fits22. Geometrical tolerancing and datums23. Application of geometrical tolerances24. Maximum material and least material requirements25. Positional tolerancing26. Surface texture27. Surface finish and corrosion of metals28. 3D annotation and product data management29. The Duality Principle e the essential link between the design intent and the verification of the end product30. Differences between American ASME Y 14.5M geometric dimensioning and tolerancing (GD&T) and ISO/BS 8888 geometrical tolerancing standards31. Cams and gears32. Springs33. Welding and welding symbols34. Engineering diagrams35. Bearings and applied technology36. Engineering adhesives37. Related standards38. Production drawings39. Design for additive manufacture40. Drawing solutions

Colin H. Simmons is an international engineering standards consultant and a member of numerous BSI and ISO committees dealing with technical product documentation and specifications. He is a former practising mechanical design engineer and author of many publications on engineering drawing, product specification and standards.

An engineering drawing is a type of technical drawing that is used to convey information about an object. A common use is to specify the geometry necessary for the construction of a component and is called a detail drawing. Usually, a number of drawings are necessary to completely specify even a simple component. These drawings are linked together by a "master drawing." This "master drawing" is more commonly known as an assembly drawing. The assembly drawing gives the drawing numbers of the subsequent detailed components, quantities required, construction materials and possibly 3D images that can be used to locate individual items. Although mostly consisting of pictographic representations, abbreviations and symbols are used for brevity and additional textual explanations may also be provided to convey the necessary information.

The process of producing engineering drawings is often referred to as technical drawing or drafting (draughting).[1] Drawings typically contain multiple views of a component, although additional scratch views may be added of details for further explanation. Only the information that is a requirement is typically specified. Key information such as dimensions is usually only specified in one place on a drawing, avoiding redundancy and the possibility of inconsistency. Suitable tolerances are given for critical dimensions to allow the component to be manufactured and function. More detailed production drawings may be produced based on the information given in an engineering drawing. Drawings have an information box or title block containing who drew the drawing, who approved it, units of dimensions, meaning of views, the title of the drawing and the drawing number.

Technical drawing has existed since ancient times. Complex technical drawings were made in renaissance times, such as the drawings of Leonardo da Vinci. Modern engineering drawing, with its precise conventions of orthographic projection and scale, arose in France at a time when the Industrial Revolution was in its infancy. L. T. C. Rolt's biography of Isambard Kingdom Brunel[2] says of his father, Marc Isambard Brunel, that "It seems fairly certain that Marc's drawings of his block-making machinery (in 1799) made a contribution to British engineering technique much greater than the machines they represented. For it is safe to assume that he had mastered the art of presenting three-dimensional objects in a two-dimensional plane which we now call mechanical drawing. It had been evolved by Gaspard Monge of Mezieres in 1765 but had remained a military secret until 1794 and was therefore unknown in England."[2]

Engineering drawings specify the requirements of a component or assembly which can be complicated. Standards provide rules for their specification and interpretation. Standardization also aids internationalization, because people from different countries who speak different languages can read the same engineering drawing, and interpret it the same way.

For centuries, until the 1970s, all engineering drawing was done manually by using pencil and pen on paper or other substrate (e.g., vellum, mylar). Since the advent of computer-aided design (CAD), engineering drawing has been done more and more in the electronic medium with each passing decade. Today most engineering drawing is done with CAD, but pencil and paper have not entirely disappeared.

Some of the tools of manual drafting include pencils, pens and their ink, straightedges, T-squares, French curves, triangles, rulers, protractors, dividers, compasses, scales, erasers, and tacks or push pins. (Slide rules used to number among the supplies, too, but nowadays even manual drafting, when it occurs, benefits from a pocket calculator or its onscreen equivalent.) And of course the tools also include drawing boards (drafting boards) or tables. The English idiom "to go back to the drawing board", which is a figurative phrase meaning to rethink something altogether, was inspired by the literal act of discovering design errors during production and returning to a drawing board to revise the engineering drawing. Drafting machines are devices that aid manual drafting by combining drawing boards, straightedges, pantographs, and other tools into one integrated drawing environment. CAD provides their virtual equivalents.

Producing drawings usually involves creating an original that is then reproduced, generating multiple copies to be distributed to the shop floor, vendors, company archives, and so on. The classic reproduction methods involved blue and white appearances (whether white-on-blue or blue-on-white), which is why engineering drawings were long called, and even today are still often called, "blueprints" or "bluelines", even though those terms are anachronistic from a literal perspective, since most copies of engineering drawings today are made by more modern methods (often inkjet or laser printing) that yield black or multicolour lines on white paper. The more generic term "print" is now in common usage in the U.S. to mean any paper copy of an engineering drawing. In the case of CAD drawings, the original is the CAD file, and the printouts of that file are the "prints".

Almost all engineering drawings (except perhaps reference-only views or initial sketches) communicate not only geometry (shape and location) but also dimensions and tolerances[1] for those characteristics. Several systems of dimensioning and tolerancing have evolved. The simplest dimensioning system just specifies distances between points (such as an object's length or width, or hole center locations). Since the advent of well-developed interchangeable manufacture, these distances have been accompanied by tolerances of the plus-or-minus or min-and-max-limit types. Coordinate dimensioning involves defining all points, lines, planes, and profiles in terms of Cartesian coordinates, with a common origin. Coordinate dimensioning was the sole best option until the post-World War II era saw the development of geometric dimensioning and tolerancing (GD&T), which departs from the limitations of coordinate dimensioning (e.g., rectangular-only tolerance zones, tolerance stacking) to allow the most logical tolerancing of both geometry and dimensions (that is, both form [shapes/locations] and sizes).

A multiview projection is a type of orthographic projection that shows the object as it looks from the front, right, left, top, bottom, or back (e.g. the primary views), and is typically positioned relative to each other according to the rules of either first-angle or third-angle projection. The origin and vector direction of the projectors (also called projection lines) differs, as explained below.

Until the late 19th century, first-angle projection was the norm in North America as well as Europe;[4][5] but circa the 1890s, third-angle projection spread throughout the North American engineering and manufacturing communities to the point of becoming a widely followed convention,[4][5] and it was an ASA standard by the 1950s.[5] Circa World War I, British practice was frequently mixing the use of both projection methods.[4]

Not all views are necessarily used.[6] Generally only as many views are used as are necessary to convey all needed information clearly and economically.[7] The front, top, and right-side views are commonly considered the core group of views included by default,[8] but any combination of views may be used depending on the needs of the particular design. In addition to the six principal views (front, back, top, bottom, right side, left side), any auxiliary views or sections may be included as serve the purposes of part definition and its communication. View lines or section lines (lines with arrows marked "A-A", "B-B", etc.) define the direction and location of viewing or sectioning. Sometimes a note tells the reader in which zone(s) of the drawing to find the view or section.

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