What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Now people often use spring washers to lock nuts and bolts, spring washers, generally stainless steel and carbon steel non-closed spiral washers, under the nut, above the flat washer, increase the friction between the nut and the bolt, used to prevent The loosening of the nut plays a role in preventing vibration and loosening, but it is often due to a radial external tension, which is caused by the tightening axial force generated by the tightening torque, and the phenomenon of open ring expansion occurs, and the hydrogen embrittlement of the spring washer often occurs. The pressure is unevenly applied to the flat washer through the spring washer, and the friction coefficient between the spring washer and the nut and the flat washer is small, resulting in vibration, rotation and relaxation.
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.
The design of the existing shaft circlip is relatively simple, and the circlip is not fast enough to be fixed in the shaft groove. When the shaft circlip receives the repeated action of radial impact load, it is prone to loosening, which affects the use of the circlip.
The advantage of wood screws is that the consolidation ability is stronger than that of nails, and they can be removed and replaced, which is more convenient to use without damaging the wood surface. This is a kind of nail specially designed for wood, and after entering the wood, it will be embedded in it very firmly. If the wood is not damaged, it is impossible to pull it out, and even if it is pulled out forcibly, it will bring out the nearby wood. Another point to note is that the wood screws must be screwed in with a screwdriver. Never knock them in with a hammer, as it will damage the surrounding wood. A screwdriver is a tool for loading and unloading wood screws. The shape matches the groove shape of the wood screw head, and there are two types: one-word and cross-shaped. In addition, there is a special screwdriver installed on the bow drill, which is suitable for loading and unloading large wood screws. Convenient and labor-saving. [2]
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