This standard applies to the diameter of twist drills used for drilling holes before tapping for common threads (according to GB/T 192-193, GB/T 196-197). JB/T 9987-1999 Diameter of twist drills used for drilling holes before tapping JB/T9987-1999 Standard download decompression password: www.bzxz.net

ICS25.10.30
Machinery Industry Standard of the People's Republic of China
JBFT9487-1999
eqVIS02306-1972
Diameter of twist drill for drilling before tapping
1999-05-20 Issued
National Machinery Industry Bureau
Implementation on 2000-01-01
JH/T9987-1999
This standard fully reflects the revision of JB228-85 "Diameter of twist drill for pinhole before tapping". During the revision, relevant technical contents were edited and modified.
This standard is equivalent to the international standard 1S02306-1972 Twist drill for tapping holes. This standard replaces JR/7228-85 from the implementation of this standard. This standard is proposed and submitted by the National Standardization Technical Committee. The responsible person for this standard is: Chengdu Institute of Standardization. The main drafters of this standard are: Shan Tigui, Hong Du, Fan Qiu
JBFr99871999
ISO Foreword
! ISO (International Organization for Standardization) is a worldwide alliance of national standards bodies (ISO member bodies) that work together to produce international standards through technical committees. Each member interested in a subject for which a technical committee has been established is entitled to be represented on that technical committee. Governmental and governmental international organizations in liaison with the committee may also participate in the development of draft international standards adopted by a technical committee before they are accepted as international standards by public notice. 15023 International Standards are submitted to or developed by its technical committee before they are accepted as international standards by the Council for the Advancement of International Standards. 1502306 was submitted to the release body in August 1971. The following parties or bodies voted against the technical conditions of the text: Austria
Czech Republic
Ireland
Israel
People's Republic of China Machinery Industry Standard
Diameter of twist drill for drilling before tapping
JB/T9987-1999
qIS02306192
Product IB/7.228-85
This standard applies to ordinary thread-reinforced (according to 2-3, G16~[diameter of twist drill for drilling before tapping. The square diameter of the twist drill listed in this standard is applicable to drilling holes under general production cases. The difference between the production parts can be added according to the actual need in the standard system of the threaded felt. In the tolerance range of the minor diameter of the threaded hole, it is recommended to use a larger size threaded felt as much as possible to reduce the load of the threaded thread and improve the life of the tap. This standard specifies the basic formula of threaded tapping diameter: 1) Calculation: (unit: mm) DP
Where: Small-high threaded drill diameter
D Nominal screw diameter:
2 Referenced standards
The provisions contained in the following standards are cited in this standard and constitute the provisions of this standard. When the technical standard is published, the version shown is valid. All standards will be revised. All parties to the standard should explore the possibility of using the latest version of the following standards: GB.192-1981 General frequency threaded thread
GB/T193.19S! Ordinary frequency series (diameter [-600mm] GB: T196-19S1 ordinary screw effect H this (diameter 1-600mm3/1971981 when the thread convergence tolerance and combination (diameter 1-355mm) 3 rent bud bodhi thread tapping before drilling month twist drill diameter with general consumption butterfly tapping effect before the standard reference must drill according to the table] service table
National Machinery Industry Bureau 5-approved
Western screw small diameter D,
SH. 6H. TH
Twist Mao suitable diameter
200-01-01 implementation
Nominal diameter
12,135
24 152
26 661
32 145 wwW.bzxz.Net
4# :47
47 147
IB/T 9987-1999
Neikejiao
4U 799
32 420
5H, AH.FF
10 tus
17 294
76 211
Twisted Ox Year
JB/T9987-1999
Network blue threaded screw ... 217 | |tt | 5 751
16 751
24,741
SE.6H, TH
31 376
33 376
: 46.376
50 376
sIt | -310
26 3511
SH, GH, 7H
25 835
27 835
49 835
376741
Deepening Diamond Certificate
.19.00
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