What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the field of mechanical design, there are a large number of connector connection structures that need to be fastened and positioned. As shown in Figure 1, the more common positioning and fastening connection methods at present are that pins 5 and fasteners are used for positioning and fastening, respectively. That is, cylindrical pins or taper pins are used for positioning, and fasteners such as screws or double-ended studs are used for fastening.
Reference standard GB 90 Fastener acceptance inspection, marking and packaging GB 196 Basic dimensions of ordinary threads (1～600mm in diameter) GB 197 Tolerance and fit of ordinary threads (1～355mm in diameter) GB 230 Test method for Rockwell hardness of metals GB 699 High-quality carbon Plain structural steel technical conditions GB 1237 Marking method of fasteners GB 5267 Electroplating layer of threaded fasteners GB6394 Determination of average grain size of metals
In order to tighten the fastener, the holding element of the tightening tool can hold the washer in engagement with the bolt to prevent the washer from rotating while allowing the rotating element of the tightening tool to rotate the nut. Such tools are disclosed, for example, in Application Serial Nos. 0/010377 and 10/120343. In this structure, since the same size washer cannot be arranged on the driving part and the fixing part, the driving part is made into the inner socket of the nut, and the fixing part is made into the outer socket of the washer, so , regular hexagonal nuts cannot be used. This is because, when just tightening the nut, the outer cavity cannot be removed since the hexagonal surface of the nut will not align with the hexagonal surface of the washer. Due to the larger diameter of the fastener formed as the outer cavity, side clearance problems may arise, thus increasing the cross-sectional profile of the hexagonal surface of the washer, which is undesirable.
The use of stainless steel screw lines: The hardness of stainless steel screw lines causes them to have different uses. Generally, they are used as small screws in life, but also as car screws and compression screws. They are widely used in normal life. Types of stainless steel screw lines: In appearance, screw lines are generally divided into fog surface spring lines and bright surface screw lines. The hardness of matte surface screw lines is higher than that of bright surface screw lines. For products with low appearance requirements and relatively high elasticity requirements. Paper, oxalic acid, fertilizer and other production equipment; photography, food industry, facilities in coastal areas, ropes, CD rods, bolts, nuts.
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