What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The slotted nut mainly refers to the hexagonal slotted nut, that is, the slot is machined above the hexagonal nut. It is used in conjunction with screw bolts with holes and cotter pins to prevent the relative rotation of the bolts and nuts, see GB6178 ~ 6181 and so on.
At present, in the production workshop, there is no special tool for removing rivets such as skew, wrong rivets, and multiple rivets. When removing these rivets, workers use homemade rivet removal tools, use a sledgehammer to remove the rivet head, and then use a sharp tool to remove the rivet rod. eject. During the removal operation, sometimes the rivet head will fly out, the speed is high, the danger is extremely high, and the labor intensity is high, which has caused many industrial accidents.
The meaning of bolt performance grade is an international standard. Bolts of the same performance grade, regardless of the difference in material and origin, have the same performance, and only the performance grade can be selected in the design. Strength grade The so-called 8.8 and 10.9 grades refer to the shear stress grades of bolts of 0.88GPa and 1.09GPa 8.8 Nominal tensile strength 800N/MM2 Nominal yield strength 640N/MM2 General bolts use XY to indicate the strength, X *100=tensile strength of this bolt, X*100*(Y/10)=yield strength of this bolt (because according to the regulations: yield strength/tensile strength=Y/10, that is, 0.Y is the yield strength ratio ) If the grade is 4.8, the tensile strength of this bolt is: 400MPa; the yield strength is: 400*8/10=320MPa. Another: stainless steel bolts are usually marked as A4-70, A2-70, and the meaning is otherwise explained Measurement: There are two main units of length measurement in the world today, one is the metric system, and the measurement unit is meters (m) and centimeters (cm). ), millimeter (mm), etc., are used more in Europe, my country and Japan and other Southeast Asian regions, the other is the British system, and the unit of measurement is mainly inches (inch), which is used more in the United States, Britain and other European and American countries. 1. Metric measurement: (decimal system) 1m2 =100 cm2=10000 mm2, imperial measurement: (8 decimal system) 1 inch = 8 inches 1 inch = 25.4 mm 3/8¢¢×25.4 =9.523, 1/4 ¢¢ The following products are indicated by their number, such as: 4#, 5#, 6#, 7#, 8#, 10#, 12#
At present, the commonly used fastener loosening prevention methods generally include non-removable anti-loosening solutions and friction-increasing anti-loosening solutions. The non-removable anti-loosening scheme uses welding, bonding or punch point riveting to change the detachable threaded connection into a non-detachable threaded connection. In the non-removable anti-loosening scheme, the threaded fasteners cannot be reused and the operation is troublesome. It is often used in some important occasions that require high anti-loosening performance without disassembly. The anti-loosening scheme that increases the frictional force uses the method of increasing the frictional force of the bolt (screw) head and the end face of the nut to achieve the purpose of anti-loosening. The anti-loosening solution that increases friction is not limited by space and can be disassembled repeatedly, but the reliability is poor. After a certain period of work, the anti-loosening effect will be reduced due to vibration and other reasons.
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