What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
According to relevant standards, the performance grades of carbon steel and alloy steel bolts are divided into more than 10 grades such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, the bolts of grade 8.8 and above are made of low-carbon alloy steel or medium Carbon steel and heat treatment (quenching, tempering) are generally called high-strength bolts, and the rest are generally called ordinary bolts. The bolt performance grade label consists of two parts of numbers, which represent the nominal tensile strength value and yield ratio of the bolt material respectively. Stainless steel bolts are divided into A1-50, A1-70, A1-80, A2-50, A2-70, A2-80, A3-50, A3-70, A3-80, A4-50, A4-70, A4-80, A5-50, A5-70, A5-80, C1-50, C1-70, C1-110, C4-50, C4-70, C3-80, F1-45, F1- 60. The first letter and number represent the stainless steel group, and the second and third numbers represent 1/10 of the tensile strength. [2]
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. , using the chip groove 134 and the chip groove 135 to be connected by different helical curvatures, so that the drill tail 13 can form a symmetrical and complete chip groove of 190 degrees.
Such flat gaskets typically include passage openings for fluids through which fluid can flow from one side of the flat gasket to the other side of the flat gasket. In addition, functional elements may be inserted into such passage openings, eg valve elements blocking passage in one direction, or orifice elements defining passage in one or both directions.
One of the steps in the screw production and processing process is to slot the screw head to facilitate the use of a screwdriver when tightening or loosening the screw. Generally, companies use manual sorting, and then use the cutting knife to slot the front end screws through the track, which is inefficient, and because the screws are not fixed, the cutting knife may easily fly out or break the blade during cutting. It is a safety problem, and after cutting, the screw head has rough workmanship and burrs, which is easy to hurt the hand.
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