本SAE航空航天标准（AS）规定了螺纹的特性——UNJ英制系列，包括表1中规定的外螺纹根部的强制控制半径。外螺纹和内螺纹的小直径提供了基本的螺纹高度。5625H，以适应外螺纹最大根部半径。包括以下详细设计要求:a.螺纹-UNJ基本轮廓和设计轮廓。b、 标称螺纹直径0.060至6.000英寸的直径-节距组合标准系列。c、 标准螺纹等级和形状公差。d、 螺纹尺寸和公差公式。e、 指定UNJ螺纹的方法。f、 选定直径的表格- 紧密公差机械螺纹应用的螺距组合。g、 螺纹表.UNJ型螺纹极限尺寸。本文件规定了螺纹各特征的几何设计——UNJ型英制系列和一致性要求。此外，本标准的目的是:a.定义选定系列统一螺纹的几何要求，对其进行修改，以在外螺纹根部提供半径。b、 确定外螺纹根部连续半径的要求。c、 制定增加内螺纹和外螺纹小直径的要求，以适应外螺纹根部半径。

This SAE Aerospace Standard (AS) specifies the characteristics of screw threads - UNJ profile inch series, including a mandatory controlled radius as specified in Table 1 at the root of the external thread. The minor diameter of both external and internal threads provides a basic thread height of.5625H to accommodate the external thread maximum root radius. The following detailed design requirements are included: a. Screw threads - UNJ basic profile and design profiles. b. Standard series of diameter-pitch combinations for nominal thread diameters from 0.060 to 6.000 inches. c. Standard thread classes and form tolerances. d. Formulae for thread dimensions and tolerances. e. Method of designating UNJ threads. f. Tables for selected diameter-pitch combinations for close tolerance mechanical thread applications. g. Tables for screw thread - UNJ profile thread limit dimensions.This document specifies the geometric design for each characteristic of screw threads - UNJ profile inch series and the conformance requirements. In addition, the purpose of this standard is to: a. Define the geometric requirements for a selected series of Unified Screw Threads, modified to provide a radius at the external thread root. b. Establish requirements for a continuous radius at the root of the external threads. c. Establish requirements for an increase in the minor diameter of both internal and external threads to accommodate the external thread root radius.