What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The heating bolt pre-stretching method makes the bolt pre-stretch to the required deformation amount by heating, and then tighten the nut. After cooling, the bolt is shortened and the connection is pre-tightened. This is a commonly used fastening method in infrastructure installations. However, it is not suitable for devices that often need to be disassembled and adjusted, because during the disassembly process, the connected parts will be heated and elongated together with the bolts, and the use of open flame heating will be limited in some occasions; the use of electric heating will make the structure of the screw It becomes complicated and increases the investment, and even if it is difficult to disassemble, such as the propeller shaft of the ship, etc., the heating method is not suitable.
1. Correctly select the product a. Before use, confirm whether the mechanical properties of the product can meet the needs of use, such as the tensile strength of the screw and the guaranteed load of the nut. The length of the screw should be selected appropriately, and the 1-2 pitch of the nut will be exposed after tightening. b. Before use, check whether the threads are rough, and whether there is iron filings or dirt between the threads, which often lead to locking. c. The fasteners can be lubricated before use. It is recommended to use butter, molybdenum disulfide, mica, graphite or talc for lubrication. Generally, dipping wax is used for lubrication and anti-locking. [1] 2. Pay attention to the use method when using it. a. The speed and force of screwing in should be appropriate, not too fast or too large. Use a torque wrench or socket wrench as much as possible, and avoid using an adjustable wrench or an electric wrench. Excessive speed will cause the temperature to rise rapidly and cause lock-up. b. In the direction of force, the nut must be screwed in perpendicular to the axis of the screw. c. The use of washers can effectively prevent the problem of over-tightening.
Sprinkle the excess standard spring washer 7 on the positioning plate 12-1 on the spring washer positioning plate 2, and shake the spring washer positioning plate 2 by hand. After a short time, the spring washer 7 will be positioned and arranged on the upper positioning plate 12-1. In the upper spring washer hole 2-7, since the width of the opening groove 12-32 of the baffle plate 12-3 is smaller than the diameter of the spring washer hole 2-7, and the thickness of the upper positioning plate 12-1 is designed according to the thickness of the spring washer 7, Only one spring washer 7 can be accommodated in the spring washer hole 2-7 of each upper positioning plate 12-1, and the excess spring washer 7 is cleaned with a brush.
Screw name broadcast 1. Machine screw 2. Self-tapping screw 3. Drilling screw 4. Wallboard screw 5. Fiberboard screw 6. Wood screw 7. Hexagonal wood screw 8. Non-prolapse screw 9. Combination screw 10. Micro screw 11. Furniture screws 12. Electronic screws
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