1.范围1。本标准是对CSA标准CAN3-B78的补充。1，包括技术图纸上所示产品的尺寸标注和公差标注。1.2第3条定义了一些专门涉及尺寸标注和公差的技术术语。CSA标准Z85，CAN3-B78中给出了图纸上常用的缩写。1和CAN3-B78。3.1.3尽管尺寸标注和公差标注的一般原则有单独的条款，但应记住这两个术语通常是不可分割的，因为图纸上规定的尺寸值代表具有适当公差的基本尺寸。因此，本标准中经常使用术语“尺寸标注”来表示尺寸限值或基本尺寸和公差的赋值。 1.4本标准中的大多数数字旨在说明尺寸标注原则，并不代表完全标注尺寸的零件。如果显示了数值，它们只是示例，旨在说明所考虑的问题，或澄清解释。大写字母用于可能出现在图纸上的注释，而小写字母的注释仅用于解释所说明的原理。出于复制目的，许多插图已经缩小，可能不符合文本中规定的用于dra机翼的尺寸和间距要求。1.5为了简单地说明本文几何公差的解释，假设所考虑的一个或多个特征除解释中涉及的误差外没有其他误差。 1.6在许多几何公差图示中，公差带的大小和形状有些夸张。这些仅用于解释目的，不打算出现在图纸上。1.7本标准中对量规的引用仅用于解释公差的正确解释，不用于控制或限制量规的设计。1.8本标准中的插图为第三角度投影，线性尺寸以毫米为单位，但所涉及的原则同样适用于第一角度投影的图纸或非国际单位制的尺寸。1.9建议根据本标准绘制的图纸在注释中反映这一点，如“根据CAN/CSA B78进行解释”。2-M91英寸。

1. Scope1.1This Standard is complementary to CSA Standard CAN3-B78.1, and covers dimensioning and tolerancing of products depicted on technical drawings.1.2Some of the technical terms dealing particularly with dimensioning and tolerancing are defined in Clause 3. Abbre viations commonly used on drawings are given in CSA Standards Z85, CAN3-B78.1 and CAN3-B78.3.1.3Although separate clauses have been assigned to the general principles of dimensioning and of tolerancing, it should be borne in mind that the two terms are often inseparable, since the value of a dimension as specified on a drawing represents a basic size with a suitable tolerance. Therefore, the term ""dimensioning"" is frequently used in this Standard to mean the assignment of values for the limits of size or the basic size and tolerance.1.4Most of the figures in this Standard are intended to illustrate a dimensioning principle, and do not represent completely dimensioned parts. Where numerical values are shown, they are examples only, intended to illustrate the point under consideration, or to clarify the interpretation. Capital letters have been used for those notes which might appear on the drawing, whereas notes in lower case letters are intended only to explain the principle being illustrated. Many illustrations have been reduced for reproduction purposes, and may not meet the size and spacing requirements specified in the text for use on dra wings.1.5For simplicity in showing the interpretation of geometrical tolerances herein, it has been assumed that the feature or features under consideration have no other errors than those with which the interpretation deals.1.6In many illustrations of geometrical tolerancing, the size and sha pe of the tolerance zones are shown somewhat exaggerated. These are for explanatory purposes only, and are not intended to appear on the drawing.1.7References to gauges in this Standard are intended only to explain the correct interpretation of tolerancing, and are not intended to control or limit the design of gauges.1.8Illustrations in this Standard are in third angle projection, and linear dimensions are in millimetres but the principles involved apply equally to drawings in first angle projection or dimensions in other than SI units.1.9It is recommended that drawings prepared in accordance with this Standard reflect this in a note, such as ""INTERPRET IN ACCORDANCE WITH CAN/CSA B78.2-M91"".