What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At present, with the development of the manufacturing industry, many parts with strange shapes are widely used in aviation, aerospace and other industrial fields, one of which is an L-shaped cylindrical pin. The upper end is provided with a 2.55×4.95 U-shaped boss. The parallelism error between the upper end face and the lower end face of the boss is required to be less than 0.01 mm. The L-shaped cylindrical pin requires high machining accuracy and is difficult to clamp on the machine tool. It is difficult to process. When the forming part is cut off, the cut surface, that is, the upper end surface of the boss, will leave a small column platform. When processing this end surface, in the prior art, a vise is generally used to process such an L-shaped cylindrical pin. Or copper sleeves are clamped, and then processed; however, due to the small size of the parts, the L-shaped cylindrical pin workpiece is difficult to clamp; due to the high precision required for each machined surface of the workpiece, when clamping with a vise , the clamping force of the vise is difficult to control, and it is easy to crush and scratch the surface of the workpiece; and when using a vise or a copper set clamp, only one workpiece can be clamped for each processing and production, and it is difficult to ensure the upper and lower planes of the parts after the clamping is completed. Parallelism machining error, resulting in low parts processing quality and low production efficiency.
The standard specifies hexagon head bolts with thread specifications of M3~M64, grades A and B. Grade A is used for bolts with D<=24 and L<=10D or L<=150mm (whichever is smaller); grade B is used for bolts D > 24 or L > 10 D or L > 150 (according to the smaller value) bolt size specification mark: thread specification D = M12, nominal length L = 80mm, performance level is 8.8, the table is the same as oxidation, A level Hexagon head bolt tag example bolt GB / T5782-86-M12 × 80 national standard common hex bolt head on the side size and cooperation national standard wrench thread diameter \ pair of edge sidewalls Skin wrench Wrench Double-ended open-end wrench Double-ended Torx wrench. The outer hexagon bolt is the most frequently used type of bolts. The main function of the external thread it has is to cooperate with the nut. Using this threaded connection method, the two parts are integrated. Grade C hexagon bolts are mainly used in steel structure machinery and equipment with relatively rough surface and low precision requirements. Grade A and Grade B hexagon bolts are mainly used in machinery and equipment with smooth surface and high precision requirements. Most of the stainless steel outer hexagon screws are full-tooth and hexagonal head full-tooth bolts. Standard: DIN933, GB5783, ISO4017, ANSIB18. 2.1, JISB1180; non-full thread bolt standards DIN931, GB5782, ISO4014, ANSIB18.2.1, JISB1180.
Riveting products provide great convenience for the unilateral connection of sheet parts, fast and efficient connection without bulky installation tools, and produce reliable standard internal and external threads, achieve cold installation after surface treatment, no pollution, is welding Effective alternative to nuts. Main applications: Auto-body, seat belt systems, bumpers, airbag systems, etc. 1. One-way drawing connection 2. Build standard internal and external threads 3. General product range: M3-M124. Materials: Carbon Steel, Stainless Steel, Aluminum 5. High quality air tools - efficient, economical, lightweight and easy to operate. Use the same principle as hand rivet nuts.
The gasket side of the above-mentioned nut assembly is in contact with the mounting surface. When the nut is tightened, the gasket squeezes the outer cone surface to make it shrink, and the cone tip faces the same direction as the nut, thereby preventing the nut from tightening, so that the nut fixing effect is not good, and at the same time When multiple nuts need to be superimposed and fixed, two adjacent nuts cannot interact with each other, resulting in poor fixing effect.
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