三、什么是尺寸的精度等级乙:怎样由公差实现配合呢?甲:国家标准中是按尺寸精度等级来具体地规定各种配合和公称尺寸的公差值的,所以,咱们在没讲由公差实现配合之前也先来谈谈尺寸精度等级。尺寸精度等级是指加工零件尺寸的准确程度。乙:它和尺寸公差有什么关系呢?甲:首先我要强调,尺寸精度和尺寸公差是两个概念。但它们之间却有 Third, what is the size of the accuracy grade B: How to achieve with the tolerance? A: The national standard is based on the dimensional accuracy level to specify the various tolerances and nominal size tolerances, so, let’s not say by Tolerance to meet before the first to talk about dimensional accuracy. Dimensional accuracy grade refers to the accuracy of machining parts size. B: What is the relationship between size tolerance and tolerance? A: First of all, let me emphasize that dimensional tolerance and dimensional tolerance are two concepts. But there is between them