What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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#
The conventional auger bit structure 1 includes a rod body 11, a screw head 12 provided on one end of the rod body 11, a drill tail 13 provided on the other end of the rod body 11, and a plurality of threads 14 arranged around the rod body 11; Wherein, the periphery of the drill tail 13 defines a parting line 15, and the parting line 15 makes the drill tail 13 symmetrically divided into a side 131 and a side 132, and a cutting end 133 is formed at the junction of the end of the side 131 and the end of the side 132, respectively. The cutting end 133 is concavely provided with a quarter-turn chip flute 134 in the same direction of the helix, and the edge 132 continues the chip flute 134 and has a quarter-turn chip flute 135 with different helical curvatures. , by connecting the chip groove 134 and the chip groove 135 through different helical curvatures, the drill tail 13 can form a symmetrical and complete chip groove of 188 degrees.
The surfaces of the existing door panels are spliced together by fasteners such as nails and bolts. For example, a door body structure for a production line disclosed in CN203807555 is used for the doors of each chamber of the coating production line. The size of the mechanism is the same, and the left and right sides of the door body can be freely opened and closed; the chamber door and the door frame are detachably connected by multiple sets of sealing components, and the sealing components include hinge devices and locking parts.
A screw suitable for a variety of tools is a single-structure threaded part, including a screw body and a screw head. The outer surface of the screw body is processed with an external thread 1, and the outer side of the screw head is formed by six screw heads. Prismatic, the top surface of each edge of the outer hexagonal prism is a boss, between each boss is an end face groove 4, and the middle of each boss is provided with an end face hole 3; the inner side of the screw head is formed by six screw heads. The side surface 5 forms an inner hexagonal prism hole, and the bottom of the inner hexagonal prism hole is processed with a cross groove 10 .
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