This standard specifies the shank diameter and drive square size of straight shank rotary tools (such as reamers, taps, etc.). This standard includes two size series: Series I and Series II. Each series lists the size in millimeters and the equivalent imperial size. GB/T 4267-2004 Shank diameter and drive square size of straight shank rotary tools GB/T4267-2004 Standard download decompression password: www.bzxz.net

ICS 25. 100. 30
National Standard of the People's Republic of China
GB/T4267—2004/ISO237:1975
Replaces GB/T4267--1984
Rotating tools with parallel shanks-Diameters of shanks and sizesof driving squares
(ISO 237:1975, IDT)
Published on February 10, 2004
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
Implemented on August 1, 2004
GB/T4267--2004/ISO237:1975
This standard is equivalent to ISO237:1975 "Dimensions of shank diameters and driving squares of straight shank rotary tools" (English version). For ease of use, the following editorial changes have been made to this standard: the foreword of the international standard has been deleted; the word "this standard" has been replaced by "this international standard"; the decimal point "" has been replaced by the decimal point ",", - Correction of printing errors: For the table in 4.1.2 of the international standard, the shank diameter range of 0.3189～1.4764" has been changed to \1.318 9~~1.476 4".
This standard replaces GB/T4267-1984 "shank diameter and drive square head dimensions for straight shank rotary tools" from the date of implementation. The main changes of this standard compared with GB/T4267-1984 are as follows: - Added "Foreword", "Chapter 1 Scope", "Chapter 2 Preferred Diameter" and "Chapter 3 Interchangeability";
Added corresponding imperial dimensions in the first series and the second series; - Added the metric and imperial conversion methods for the shank diameter and square head dimensions; - Added the value range of the a/d ratio of the first series and the second series; Added table notes and footnotes in 4.1.1 and 4.1.2, and added table notes in 4.2.1 and 4.2.2. This standard is proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Tool Standardization. The drafting unit of this standard: Chengdu Tool Research Institute. The main drafter of this standard: Xia Qian.
The previous versions of the standard replaced by this standard are: -GB/T 4267—1984. bzxz.net
1 Scope
GB/T 4267—2004/ISO·237:1975 Shank diameter and drive square head dimensions of straight shank rotary tools This standard specifies the shank diameter and drive square head dimensions of straight shank rotary tools (such as reamers, taps, etc.). This standard includes two size series: the first series and the second series. Each series lists the dimensions in millimeters and the equivalent imperial dimensions.
For each series, the drive square head dimensions applicable to a given diameter are also listed. The entire diameter range is divided into several diameter segments. The corresponding standard square head dimensions are listed not only for the first series, but also for each diameter segment of the second series, because it is completely necessary to subdivide some use occasions in the small diameter area. In each metric size table, the square head opposite side dimension a and the preferred diameter d are arranged in the priority number R20 series; the upper and lower limits of each diameter segment are the intermediate values ​​taken in the priority number R40 series. In each imperial size table, the values ​​of a and d are converted from the corresponding metric values, the square head dimensions are taken to the third decimal place, and the diameter dimensions are taken to the fourth decimal place.
In the first series, in addition to listing the upper and lower limits of each diameter segment, each table also lists the preferred diameter for each diameter segment (see the following table). The ratio of the square head opposite side dimension to the preferred diameter is equivalent to the theoretical optimum value a/d=0.8. In any diameter segment, the ratio a/d is between 0.75 and 0.85 for the first series and between 0.80 and 0.85 for the second series, calculated on the basis of the nominal values ​​of α and d, and not less than 0.72 in the worst case, taking into account their tolerances. 2
Preferred diameters (see Table 1)
Interchangeability
0,2795
Sizes in millimeters or inches shall be such that the dimensions of the square heads corresponding to one diameter segment are identical. 1.3976
In addition, since the upper and lower limits of the inch and millimeters diameter segments are exactly equal, two driving square heads of diameter (whether inches or millimeters) belonging to the same diameter segment are identical.
GB/T 4267--2004/IS0 237: 19754 Shank diameter and driving square head (see Figure 1) 4.1 Series
Dimensions in millimeters (see Table 2)
Shaft diameter
Square head
Shaft priority
Shaft diameter:
Optional types (for small diameters) Square head
Among the possible diameters in each diameter segment, select the value closest to the preferred diameter (see the last column of the table). Shank priority
4.1.2 Dimensions in inches (see Table 3) Shank diameter:
Transmission square head
Shank priority
Shank diameter
GB/T4267—2004/ISO237:1975
Transmission square head
Among the possible diameters in each diameter segment, select the value closest to the preferred diameter (see the last column of the table).
Note: For 4.1.1 and 4.1.2
Tolerance:
Tolerance of square head a: h12, including shape and position errors (recommended manufacturing tolerance: h11); 1)
Tolerance of square hole size a for mounting square head: D11; Shank tolerance: Precision force tools: h9t
Other tools: hl1.
For imperial dimensions, the metric tolerance values ​​of h9, h11, h12 and D11 are directly converted into inches. Shank priority
GB/T 4267-2004/ISO 237: 19754.2 Second series (unlikely to be used)
Dimensions in millimeters (see Table 4)
Shank diameter.
Transmission square head
Shaft diameter
Among the possible diameters in each diameter segment, select the value closest to the upper limit4
Transmission square head
4.2.2Dimensions in inches (see Table 5)Shaft diameter:
Transmission square head
Shaft diameter"
Among the possible diameters in each diameter segment, select the value closest to the upper limitGB/T4267--2004/ISO237:1975
Transmission square head
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