GB/T 47356.2-2026Aerospace - Lead and runout threads - Part 2: Internal threads (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".

Drafting.

This document is Part 2 of GB/T 47356 "Aerospace Thread Guiding and Finishing". GB/T 47356 has published the following...

part.

---Part 1: Rolled External Threads;

---Part 2: Internal Threads.

This document is equivalent to ISO 3353-2:2020 "Aerospace - Threading guidance and finishing - Part 2: Internal threads".

Some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.

This document was proposed and is under the jurisdiction of the National Aircraft Standardization Technical Committee (SAC/TC435).

Introduction

GB/T 47356 "Aerospace Thread Guiding and Finishing" is proposed to consist of two parts.

---Part 1: Rolled External Threads. The purpose is to specify the guiding and finishing requirements for rolled external threads in the aerospace field, as well as the occurrence of...

The testing methods to be used in case of disputes.

---Part 2: Internal Threads. The purpose is to specify the requirements for the guidance and termination of internal threads in blind holes, as well as the requirements for relief grooves, in the aerospace field.

Aerospace thread guide and finish Part 2: Internal Threads

1 Scope

This document specifies the requirements for the guiding and finishing of internal threads and the relief groove in the aerospace field.

This document applies to blind hole internal threads.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

ISO 5855-1 Aerospace MJ threads - Part 1: General requirements) Note. GB/T 43924.1-2024 Aerospace MJ Threads - Part 1: General Requirements (ISO 5855-1:1999, MOD)

3 Terms and Definitions

The following terms and definitions apply to this document.

Threaded lead thread in the incomplete thread region at the beginning of an internal or external thread, the root of the thread is fully formed but the crest is not fully formed.

thread end runoutthread During the cutting process, there is an incomplete thread area between the end of the complete thread and the end of the blind hole.

undercut

A groove formed at the bottom of the hole to define the complete thread range (except at the intersection of the last thread and the side of the groove).

The axial distance is one pitch (P), and the thread profile has the crest and root within the specified requirements (see Figure 1).