This standard specifies the basic requirements for position tolerance, material and hardness, appearance and surface roughness, marking and packaging of flat bottom countersinks with guide pins. This standard applies to flat bottom countersinks produced in accordance with GB/T4260 and GB/T4261. GB/T 4262-2004 Technical conditions for flat bottom countersinks GB/T4262-2004 Standard download decompression password: www.bzxz.net

ICS 25. 100. 30
National Standard of the People's Republic of China
GB/T4262-2004
Replaces GB/T4262-1984
Flat-bottom strontium drill
Technical conditions
Counterbores-Technical requirement2004-02-10 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
2004-08-01 Implementation
This standard replaces GB/T4262--1984 "Technical conditions for flat-bottom strontium drill" from the date of implementation. This standard has the following changes compared with GB/T4262~-1984: The writing format is in accordance with GB/T 1.1—2000;
Drill material changed from "W18Cr4V" to "W6Mo5Cr4V2"; - Performance test chapter cancelled;
Surface roughness in type size is included in this standard; The symbol is adjusted.
This standard is proposed by China Machinery Industry Federation. This standard is under the jurisdiction of the National Tool Standardization Technical Committee. The drafting unit of this standard: Chengdu Tool Research Institute. The main drafters of this standard: Shen Shichang, Nie Kexing. The previous releases of the standards replaced by this standard: GB/T4262-1984.
GB/T4262-2004
1 Scope
Flat-bottomed strontium drill
Technical conditions
GB/T 4262—2004
This standard specifies the basic requirements for position tolerance, material and hardness, appearance and surface roughness, marking and packaging of flat-bottomed strontium drills with guide pins.
This standard applies to flat-bottomed strontium drills produced in accordance with GB/T4260 and GB/T4261. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version shall apply to this standard. GB/T4260 Straight shank flat bottom strontium drill with integral guide pin (GB/T4260-2004, ISO4206:1991, MOD) GB/T4261 Morse taper shank flat bottom strontium drill with replaceable guide pin (GB/T4261-2004, ISO4207:1977, MOD) 3 Position tolerance
The position tolerance of flat bottom strontium drill is shown in Table 1. Table 1
d≤18
Radial runout of circumferential blade to common axisRadial runout of guide post to common axis
Axial runout of end blade
4 Materials and hardness
d>18～30
Unit: mm
d>30～~60
4.1 Strontium drill is made of W6Mo5Cr4V2 or other high-speed steel with equivalent performance. The handle of welded strontium drill is made of 45 steel or other steel with equivalent performance.
4.2 Hardness of strontium drill:
Working part: 63HRC～66HRC
Handle or flat tail: 40HRC～55HRC for integral strontium drill and 30HRC～45HRC for welded strontium drill. 5 Appearance and surface roughness
5.1 The drill surface shall not have defects such as cracks, scratches, rust and grinding burns that affect the performance. 5.2 The upper limit of surface roughness is:
Front, back and cylindrical land: Rz6.3μm; shank outer circle and guide pin outer circle: Rao.8μm; - Hole for guide pin: Ral.6 μm.
GB/T 4262—2004
6 Marking and packaging
6.1 Marking
6.1.1 The product should be marked with:
The trademark of the manufacturer or seller;
The diameter of the drill and the diameter of the guide pin;
The code of high-speed steel (HSS).
The packaging box should be marked with:
Name, address and trademark of the manufacturer or seller; -Strontium drill mark;
High-speed steel grade or code:
Applicable bolt or screw specifications;
Number of pieces;
Year and month of manufacture.
6.2 Packaging Www.bzxZ.net
The drill should be treated with rust prevention before packaging, and the packaging should be firm to prevent damage during transportation. 2
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