GB/T 25672-2021Hammer drill bit and shell hammer drill bit (English PDF)

Foreword

This document is in accordance with GB/T 1.1-2020 "Guidelines for Standardization Part 1: Structure and Drafting Rules of Standardization Documents". To be drafted.

This document replaces GB/T 25672-2010 "Electric Hammer Drills and Jacketed Electric Hammer Drills". Compared with GB/T 25672-2010, except for structural adjustments In addition to editorial changes, the main technical changes are as follows.

a) Deleted the normative reference document GB/T 3478.1 (see Chapter 2 of the 2010 edition);

b) Change GB J107 "Concrete Strength Inspection and Evaluation Standard" to GB/T 50107 "Concrete Strength Inspection and Evaluation Standards (see Chapter 2, Chapter 2 of the 2010 edition);

c) Increase the size of the electric hammer drill with a diameter of 52mm (see Table 1);

d) In the marking example, the overhang length is deleted, and it is represented by the total length L. The sleeve-type electric hammer drill increases the sleeve-type tool length l1 (see 5.4);

e) M-shaped shank (five-slot round shank) is added to the shank type (see 5.3);

f) The surface roughness Rz is uniformly changed to Ra, and the surface roughness of the cylindrical part of the connection part of the sleeve type electric hammer drill center positioning drill is increased. Ra3.2µm (see 6.1.2, 6.1.3);

g) The test material is changed from "C28" concrete to "C30" concrete (see 6.4.1.3, see 5.4.1.3 of the 2010 edition);

h) The test method is changed from "drilling through holes" to "drilling blind holes" (see 6.4.3, see 5.4.3 of the 2010 edition);

i) The type and size of M-shaped shank (five-slot round shank) have been added to Appendix A (see A.13).

1 Scope

This document specifies the type and size, appearance and surface roughness, position tolerance, material and hardness, performance of electric hammer drill and sleeve electric hammer drill Basic requirements for testing, marking and packaging.

This document is applicable to electric hammer drills with a diameter ranging from 5mm to 52mm for drilling holes in concrete, bricks and other materials without metal inclusions.

And a sleeve type electric hammer drill with a diameter of 25mm~150mm for drilling holes in bricks, blocks, lightweight walls and other materials.

2 Normative references

The contents of the following documents constitute the indispensable clauses of this document through normative references in the text. Among them, dated quotations Only the version corresponding to that date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 18376.2 Cemented Carbide Grades Part 2: Cemented Carbide Grades for Geology and Mining Tools

GB/T 50107 Concrete Strength Inspection and Evaluation Standard

3 Terms and definitions

There are no terms and definitions that need to be defined in this document.

4 Symbols

The following symbols apply to this document. d---The diameter of the electric hammer drill or sleeve type electric hammer drill; d1---The diameter of the shank positioning circle of the electric hammer drill; l ---The overhang length of the electric hammer drill; l1---The length of the sleeve type electric hammer drill sleeve knife; l2---The overhang length of the sleeve type electric hammer drill;

L---Total length of electric hammer drill or sleeve type electric hammer drill.

5 Type and size

5.1 The type and size of the electric hammer drill are in accordance with Figure 1 and Table 1.