Briefly Describe the ANSI and ISO Drafting Standards

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The Answer is Two sets of drafting standards are accepted worldwide: ANSI (inch-metric) and ISO (metric). Almost all practices (dimensioning; line types and thicknesses; welding symbols; drawing sheet sizes; GD&T; screw threads; surface textures; finish symbols; etc.) are now the same in either system or roughly comparable. Most major technical differences are beyond the scope of this text. Of course, the most obvious difference between the two is that U.S. multi-view drawings use third-angle projection. Europe and Asia follow ISO practices and view objects from first-angle projection. ANSI recommends decimal-inch dimensioning and notes on U.S. drawings to be unidirectional. ISO default practice allows aligned decimal millimeter dimensions. Both standards are used throughout North America.

Briefly Describe the ANSI and ISO Drafting Standards

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