This standard specifies the structural elements and tightening torque of the locking part of nylon inserts. This standard applies to general-purpose locking bolts and screws with cylindrical nylon inserts. The types and dimensions of other parts of such bolts and screws shall comply with the provisions of the corresponding national standards. JB/T 5399-1991 Structural elements and tightening torque of the locking part of nylon insert locking bolts and screws JB/T5399-1991 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T5399——91
Structural elements and tightening torque of locking bolts and screws with nylon inserts
Published on 1991-06-25
Published by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Implemented on 1992-07-01
Mechanical Industry Standard of the People's Republic of China
Structural elements and tightening torque of locking bolts and screws with nylon inserts
1 Subject content and scope of application
This standard specifies the structural elements and tightening torque of the locking part of nylon inserts. JB/T5399—91
This standard applies to locking bolts and screws with cylindrical nylon inserts for general use. The types and sizes of other parts of such bolts and screws shall comply with the provisions of the corresponding national standards. Reference standards
Basic dimensions of common threads
Tolerances and fits of common threads
External threaded partsEnds of threaded parts
Types and sizes of nylon inserts and locking parts3
Types and sizes of nylon inserts
Nylon inserts are cylindrical, and their types are shown in Figure 1, and their sizes are in accordance with Table 1. Figure 1
Dimensions of nylon inserts
Thread specifications
Insert diameter
Insert heightwww.bzxz.net
Types and sizes of nylon insert sockets
The types of nylon insert sockets are shown in Figure 1, and their sizes are in accordance with Table 2. Approved by the Ministry of Machinery and Electronics Industry on June 25, 1991, M4
Implementation on July 1, 1992
Thread gauge
Hole seat diameter
Hole seat depth
3.3·Insert dimensions of nylon inserts
JB/T5399—91
Dimensions of nylon insert hole seats
The control dimensions of the center position and protruding parts of the nylon inserts shall be in accordance with Table 3 (see Figure 1). Table 3
Thread specification
Nylon insert
Center position
Protruding thread
Control dimension
Center position and protruding part control dimension of nylon insertM3
After the nylon insert is installed in the hole seat, its protruding part should be controlled within the limit that allows the locking part to pass through the smooth ring gauge with a diameter equal to the maximum major diameter of the thread by white or finger pressure. 3.4 Dimensions of the threaded part of bolts and screws and the complete thread length extending from the nut3.4.1 The dimensions, tolerances and ends of the threaded part of bolts and screws shall comply with the provisions of GB196, GB197 and GB2. 3.4.2 The complete thread length of the threaded part of bolts and screws extending from the nut shall be at least 1 times the pitch and at most 2 times the pitch. 3.5 Dimensional requirements for internal threaded parts
3.5.1 The dimensions and tolerances of the threaded part of internal threaded parts shall comply with the provisions of GB196 and GB197. Internal threaded parts shall have a complete thread with at least 6 times the pitch length. 3.5.2
The entry end of the threaded hole of the internal threaded part shall be chamfered, and its outer end diameter shall be at least 0.4mm larger than the major diameter of the internal thread, see Figure 2. 3.5.3
(--D) >0.4mm
Material and working temperature of nylon inserts
JB/T5399--91
4.1 The recommended material for nylon inserts is nylon 66 or nylon 1010, and the technical requirements for the materials shall comply with the provisions of relevant standards. 4.2 The working temperature of nylon inserts is -50 to +100℃. 5 Materials for threaded parts
5.1 The materials for bolts and screws shall comply with the provisions of relevant standards. 5.2 The materials for internal threaded parts shall be the same as those for nylon insert locking bolts and screws. The performance grade of nuts shall not be lower than that of bolts and screws.
6 Tightening torque of nylon insert locking bolts and screws 6.1 After the nylon insert locking bolts and screws are screwed together with the internal threaded parts, their tightening torque shall meet the requirements of Table 4. Table 4 Tightening torque requirements of nylon insert locking bolts and screws
Maximum torque for the first screw-in
Not greater than
Minimum torque for the fifth screw-out
Not less than
The tightening torque shall be measured in accordance with the provisions of the relevant test standards. The measurement shall be carried out under the case temperature condition, and the temperature rise of the nut shall not exceed 24℃. Additional remarks:
This standard is proposed and managed by the National Technical Committee for Standardization of Fasteners. This standard was drafted by the Ministry of Aerospace Industry, Beijing University of Aeronautics and Astronautics. The main drafters of this standard are Guo Keqian and Li Ling. 3
People's Republic of China
Mechanical Industry Standard
Nylon Insert Locking Bolt, Screw Locking Part Structural Elements and Locking Torque
JB/T5399--91
Published and distributed by the Mechanical Standardization Research Institute of the Ministry of Machinery and Electronics Industry (P.O. Box 8144, Beijing 100081)
Copyright reserved. No reproduction allowed
Printed by Printing Factory, Qinghe County, Hebei Province
Format 880×1230
1/16 Sheet 1/2 Number of words 6000
First edition in October 1991
First printing in October 1991
Print number 00.0011000 Price 0.80 yuan
No. 0227
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