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Geometric dimensioning and tolerancing is a system to define geometric symbols to help Machine designer and Manufacturer to communicate each other over the detail drawings ( or MBD ( Model Based Definition). It is a system of symbols, rules and definitions used to define the geometry of mechanical parts. Geometric dimensioning and tolerancing provides a comprehensive system for symbolically defining the geometrical tolerance zone.

What is Technical Drawings?

Technical Drawing is a type of special  universal graphic  language used between Engineers (Mechanical, Electrical etc.), Architects, Drafters, Designers, CAD Operators. Technical Drawing is a universal language of engineering used in the design process for solving problems, quickly and accurately visualizing objects, and conducting analysis. Technical drawing is the formal and precise study of the procedures, tools, supplies, skills and techniques used to record and communicate the shape, size, features and precision of physical objects of a product. These experts are using views and numbers/dimensions that should be understood by anyone regardless of the language they speak. Technical drawing can be made by using CAD applications, Freehand or Mechanical methods. In order for drawing to be dimensioned and understood, we need follow standards that every company in the world must follow. These standards are ISO, ANSI, DIN, JIS,CEN (European Standards Organization), MIL, DOD(The United States military has two organizations that develop standards)etc.

International Paper Size Standards

ISO 216 Paper Sizes: In the ISO Standard Paper Size System, the height-to-width ratio of all pages is the square root of two (√ 2 ). it is based on the German DIN 476 standard for paper sizes.ISO 216 standard paper sizes are based on the metric system.ISO 216 standard paper sizes shown in the following chart. ISO paper sizes can be defined with "A", "B" and "C" sizes. But we will give information about "A" series paper sizes.

ISO Format A series Paper SizesB series Paper SizesC series Paper Sizes
Size Metric (mm)Inch (in)Metric (mm)Inch (in)Metric (mm)Inch (in)
2A01189× 168246.81x46.81     
1594 x 84123.39x33.11707x100027.83x39.37648x91725.51x36.10
5 148x2105.83x8.27176x2506.93x9.84162x2296.38x9.02
9 37x521.46x2.0544x621.73x2.4440x571.57x2.24

4A0 and 2A0 are the DIN 476 Oversize Formats. The paper sizes bigger than A0, 4A0 and 2A0, aren't formerly defined by ISO 216. But These are commonly used for oversized paper. The origin of these formats is in the German DIN 476 standard.ISO 216 was derived from DIN 476. There are some A series paper size tolerances used by ISO 216. These are ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in, ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in), and ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in).

ANSI Standard Paper Sizes (ANSI/ASME Y14.1)

ANSISizeSimilar ISO A Sizes
Metric (mm)InchesMetric (mm)
ANSI A215.9 x 279.48.5 x 11A4
ANSI B279.4 x 431.811 x 17A3
ANSI C431.8 x 558.817 x 22A2
ANSI D558.8 x 863.622 x 34A1
ANSI E863.6 x 1117.634 x 44A0

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