GB/T 20333-2023Taps for parallel and taper pipe threads general dimensions and marking (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:

This document replaces GB/T 20333-2006 "Basic Dimensions and Signs of Taps for Cylindrical and Conical Pipe Threads", and GB/T 20333-

Compared with:2006, except for structural adjustment and editorial changes, the main technical changes are as follows:

--- Added a description of the ISO symbol for the logo (see Chapter 5):

This document is equivalent to ISO 2284:2017 "Basic dimensions and signs of hand taps for cylindrical and conical pipe threads":

The following minimal editorial changes have been made to this document:

--- Added Appendix NA (informative):

1 Scope

This document specifies the basic dimensions and markings for taps for cylindrical and conical pipe threads:

This document applies to the following two types of taps:

---Cylindrical pipe thread taps (see Figure 1 and Table 1);

--- Conical pipe thread taps (see Figure 2 and Table 2):

The threads referred to above comply with ISO 7-1 and ISO 228-1:

Appendix A gives the calculation method of the dimensions of each part, and Appendix B gives the correspondence between this document and the ISO 13399 series of document symbols:

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text: Among them, dated references

For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to

this document:

Note: GB/T 4267-2004 The diameter of the shank of straight shank rotary tools and the size of the transmission square head (ISO 237:1975, IDT)

Note: GB/T 20334-2006 G series and Rp series pipe thread grinding tap thread size tolerance (ISO 5969:1979, IDT)

3 Terms and Definitions

This document does not have terms and definitions that need to be defined:

4 basic dimensions

The basic dimensions of each part of the tap are in Table 1 and Table 2: The dimensions of the shank of the tap and its square head shall be in accordance with ISO 237, with the following tolerances:

--- Tolerance of dimension d1:

* The precision shank tolerance is h9;

* Other shank tolerances are h11:

--- Tolerance of square head dimension a:

* h11;

* h12 (including shape and position error relative to the handle):

5 signs

Taps manufactured in accordance with this document and the requirements of ISO 5969 shall be marked on the shank as follows: