What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The nut specification table is to unify all kinds of nuts in detail, and use the table to subdivide some specifications of the nuts. There are many types of nuts, and there are nuts of different materials. Each type of nut has different specifications, and each type of screw also has its mechanical properties and functions. · Square nut grade C GB 39-88 · Hexagonal nut grade C GB /T41-2000 · Hexagonal thick nut GB 56-88 · Wing nut GB 62-88 · Ring nut GB 63-88 · Combined cap nut GB 802 -88 · Spherical Hex Nut GB 804-88 · Fastening Nut GB 805-88 Knurled High Nut GB 806-88 · Knurled Thin Nut GB 807-88 · Small Hexagonal Extra Flat Fine Thread Nut GB 808-88 · Embedded Round nut GB 809-88 · Small round nut GB 810-88 · Round nut GB 812-88 End hole round nut GB 815-88 · Side hole round nut GB 816-88 · Slotted round nut GB 817-88 · Type 1 non-metallic insert hexagonal lock nut GB /T 889.1-2000 · Type 1 non-metallic insert hexagonal lock nut with fine thread GB /T 889.2-2000 · Cap nut GB 923-88 · Type 1 hexagonal nut GB / T 6170-2000 · Type 1 Hexagonal Nuts with Fine Thread GB /T 6171-2000 · Hexagonal Thin Nuts GB /T 6172.1-2000 · Non-metallic Insert Hexagonal Locking Thin Nuts GB /T 6072.2-2000 · Hexagonal Thin Nuts with Fine Pitch GB /T 6173-2000 · Hexagonal thin nuts without chamfer GB /T 6174-2000 · Type 2 hexagon nuts GB /T 6175-2000 · Type 2 hexagon nuts with fine pitch GB /T 6176-2000 · Hexagon flange nuts GB / T 6177.1-2000 · Hexagon flange face nuts with fine pitch GB /T 6177.2-2000 · Type 1 hexagon slotted nut - Grade A and B GB 6178-86 · Type 1 hexagon slotted nut - Grade C GB 6179-86 · 2 Type Hexagonal Slotted Nuts-A and B Grades GB 6180-86 Hexagonal Slotted Thin Nuts-A and B Grades GB 6181-86 Type 2 Non-metallic Insert Hexagonal Lock Nuts GB/T 6182-2000 Non-metallic Inserts Hexagon flange face lock nuts for non-metal inserts GB /T 6183.1-2000 · Non-metallic insert hexagonal flange face lock nuts with fine thread GB /T 6183.2-2000 · Type 1 all-metal hexagonal lock nuts GB /T 6184-2000 · Type 2 all-metal hexagonal lock nut GB /T 6185.1-2000 · Type 2 all-metal hexagonal lock nut fine pitch GB /T 6185.2-2000 · Type 2 all-metal hexagonal lock nut Grade 9 GB /T 6186-2000 · Full Metal Hexagon Flange Face Lock Nuts GB /T 6187.1-2000 · All Metal Six Angle flange face locking nut fine pitch GB /T 6187.2-2000 · Type 1 hexagon slotted nut with fine pitch A and B grades GB 9457-88 · Type 2 hexagonal slotted nut with fine pitch A and B grade GB 9458-88 · Hexagonal Slotted Thin Nut Fine Thread Grade A and B GB 9459-88 · Welded Square Nut GB /T 13680-92 · Welded Hexagonal Nut GB /T 13681-92 · Flat Head Rivet Nut GB /T 17880.1-1999 · Countersunk Head Rivet Nut GB /T 17880.2-1999 · Small countersunk head rivet nuts GB /T 17880.3-1999 · 120° small countersunk head rivet nuts GB /T 17880.4-1999 · Flat head hexagonal rivet nuts GB /T 17880.5-1999 · Hexagonal nuts for precision machinery GB /T 18195-2000
When using ordinary hexagon head bolts or ordinary T-bolts with the oval groove structure, the bolts need to be inserted from the back of the groove. When the bolts cannot be inserted from the back of the groove due to the structural limitations of the steel base or the platform itself, it is often necessary to open the installation surface. Large diameter hand holes allow for easy mounting of bolts, which weakens the inherent strength and rigidity of a steel base or platform.
The embedded nut is made of copper nuts made of various embossed wires (usually lead brass, such as H59, 3604, 3602). The embedded knurled copper nuts that we come into contact with on a daily basis are processed by precision automatic lathes. The reference standard for embedded knurled copper nuts comes from the national standard GB/T809. The main operation method of the anti-loose nut is to inject the embedded knurled copper nut. After heating, it is embedded into the plastic part or directly injected into the mold. If the mold is injection-molded, the melting point of PA/NYLOY/PET is above 200°C , After the embedded nut is hot melted into the plastic part, the temperature rises rapidly. After injection molding, the plastic body rapidly cools and crystallizes and becomes hard. If the embedded nut temperature is still at a high temperature, it may fall to the place where the copper nut contacts the plastic part. Start to loosen or crack. Therefore, copper nuts are used instead of carbon steel nuts in the injection molding of embedded nuts. There are two ways to form the external knurling of the embedded copper nut. One is to use copper raw material to draw the knurl and then to produce it on the upper equipment. Generally, the pattern of this method is straight, and the other is to use The round copper material is directly embossed while tapping during the production process. This processing method can produce some non-standard size knurled copper nuts. The embossed shape of the embedded copper nut can be selected by the user, such as mesh, Character embossing, herringbone embossing and other knurling patterns.
The most important link in the development and design of fasteners is quality control. There are several major points from the feed to the finished product shipment, and these major points have different inspection methods. First of all, the feed is related to appearance, size, elements, performance, detection of harmful substances, etc.; the process is more about appearance, size, percussion test, forging flow line; heat treatment is more about appearance, hardness, torque, tension , metallography, etc.; the surface treatment is more about some hydrogen embrittlement tests, coatings, salt spray, etc., including a detection of harmful substances in shipments. In size and appearance inspection, the common ones are quadratic element, contour measuring instrument, three-coordinate measuring instrument, image sorting machine (this is a full selection machine); in mechanical and chemical inspection, there are mainly hardness machines (Rockwell and Vickers). ), tensile machine, metallographic microscope; in material testing, there is a spectrum analyzer and a salt spray testing machine.
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