What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The profile of the American National thread (60 profile angle and H/8 flatness) is different from the Wyeth thread profile (55 profile angle and H/6 flattening height). American National Thread is widely used in regions and industries that are influenced by American industry. In World War II, due to the inconsistent thread standards used by the Allies, the logistical supply difficulties caused serious economic losses and casualties to the Allies. Immediately after the end of World War II, the United States, the United Kingdom, Canada and other allies immediately began to formulate a unified thread standard among allied countries, and promulgated a unified thread standard in 1948. Because the economic strength and military strength of the United States dominated the Allied forces at that time, the unified thread was mainly formulated according to the national thread standard of the United States. Unity; the latter letter N is derived from the N designation for American National Threads. Since then, the unified thread began to squeeze the original use market of the British Whitworth thread.
screw generally includes a screw head, a screw part and a screw tail. In the traditional screw processing, the screw head and the screw part are punched out first, and then the threaded part is processed on the screw shank through the turning process. When the screw head is traditionally punched, the screw head is easily damaged due to the large punching force.
The opening circlip is widely used in many industrial fields and plays a role in limiting the position of the parts. When in use, as long as the circlip is installed in the circlip groove of the part, the position of other matching parts can be effectively limited, so as to avoid the axial displacement of the matching parts. Since some opening circlips do not have circlip pliers installation holes, circlip pliers cannot be used and can only be installed by hand, which not only cannot effectively ensure the installation quality of the circlip, but also limits the efficiency of installation work.
Generally speaking, the metal plate needs to open holes for inserting the rivets, and then press the two sides of the metal plate along the positive direction of the metal plate with a jig, so that the metal plate is deformed in the plane direction, which makes the inner edge of the hole Shrink and fit the rivet. Existing riveting techniques are not suitable for thin sheets. Because the thin plate does not have enough thickness to compress in its forward direction, the insufficient deformation in the forward direction causes enough deformation in the plane direction to insert the rivet, so the rivet cannot be firmly fixed to the thin plate.
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