GB/T 9144-2025General purpose metric screw threads - Preferable plan (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

GB/T 9144 "Preferred series of common thread" and GB/T 192 "Common thread profile", GB/T 193 "Common thread diameter and Pitch series", GB/T 196 "Basic dimensions of common threads", GB/T 197 "Tolerances of common threads", GB/T 2516 "Tolerances of common threads" GB/T 9145 "Limit Dimensions of Medium Precision, Preferred Series of Ordinary Threads" and GB/T 15756 "Limit Dimensions of Ordinary Threads the "Thread Limit Dimensions" together constitute the national standard system of "Ordinary Thread".

This document replaces GB/T 9144-2003 "Preferred series of common threads". Compared with GB/T 9144-2003, in addition to structural adjustments and in addition to editorial changes, the main technical changes are as follows.

--- Expand the maximum nominal diameter range from 64mm to 100mm (see Chapter 1 and Table 1, Chapter 1 and Table 1 of the 2003 edition);

This document is modified to adopt ISO 262:2023 "ISO - Selection series for metric plain thread bolts, screws, studs and nuts".

The technical differences between this document and ISO 262:2023 and their reasons are as follows.

--- ISO 5408 (see Chapter 3) has been replaced by the normative reference GB/T 14791 to adapt to my country's technical conditions and increase operability Sexuality;

--- Clarified the practical application areas of the standard (see Chapter 1).

The following editorial changes were made to this document.

--- Change the name of the standard to "Preferred series of common threads";

--- The informative reference GB/T 192 replaces ISO 68-1, GB/T 193 replaces ISO 261, and GB/T 197 replaces ISO 965-1 (see Chapters 1, 5 and references).

1 Scope

This document specifies the preferred series of common threads (general purpose metric threads M), which are derived from the common threads specified in GB/T 193.

The thread is selected from the standard series, with a nominal diameter range of 1mm ~ 100mm, and the tooth type of the ordinary thread conforms to GB/T 192 Regulation.

This document applies to bolts, screws, studs and nuts and to metric fastening threads used in general mechanical engineering.

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB/T 14791 Thread Terminology (GB/T 14791-2013, ISO 5408:2009, IDT)

3 Terms and definitions

The terms and definitions defined in GB/T 14791 apply to this document.

4 Preferred series

The preferred series of diameter and pitch of common threads should comply with the requirements of Table 1.

Table 1 Preferred series of common threads

Unit is mm

Nominal diameter D, d Pitch P 1st choice 2nd choice Coarse pitch Fine pitch 1.2 1.4 0.25 0.25 0.3 1.6 1.8 0.35 0.4 2.5 3.5 0.45 0.5 0.6