What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the automobile industry, it is often necessary to install bolts at the opening of a closed cavity to fix and connect other parts. However, the diameter of the opening of the closed cavity is often larger than that of the head of the bolt, so it is necessary to set a strip-shaped spacer on the head of the bolt, so that the spacer can penetrate the opening longitudinally, and then block the opening horizontally, so as to be stuck with an upside-down buckle. Bolt head. However, since the bolt body of the bolt has a certain length, the manual vertical and horizontal turning operation after the strip spacer penetrates the opening is very difficult, and it is easy to drop the bolt and the spacer into the airtight cavity together, which greatly increases the assembly time. Increased labor costs.
NPT, PT, G are all pipe threads. NPT is the abbreviation of National (American) Pipe Thread, which belongs to the American standard 60-degree taper pipe thread, which is used in North America. National standards can be found in GB/T12716-1991 PT is the abbreviation of Pipe Thread, which is a 55-degree sealed conical pipe thread, which belongs to the Whitworth thread family and is mostly used in Europe and the Commonwealth of Nations. Commonly used in water and gas pipe industry, the taper is specified as 1:16. The national standard can be found in GB/T7306-2000 G is a 55 degree non-threaded sealing pipe thread, which belongs to the Whitworth thread family. Marked as G stands for cylindrical thread. National standards can be found in GB/T7307-2001 In addition, the 1/4, 1/2, 1/8 marks in the thread refer to the diameter of the pipe, and the unit is inches. People in the industry usually refer to thread size in points, 1 inch equals 8 points, 1/4 inch is 2 points, and so on. G seems to be the general name for pipe threads (Guan), and the division of 55 and 60 degrees is functional, commonly known as pipe circle. That is, the thread is machined from a cylindrical surface. ZG is commonly known as pipe cone, that is, the thread is made of a conical surface. The general water pipe joints are like this. Rc means conical internal thread ZG means taper pipe thread, 3/4 means inch mark, which is 3/4 inch conical pipe Thread, there is in the Hardware Manual. The national standard stipulates that the major diameter of ZG 3/4 thread is 26.44 mm. Please refer to Metric, American and British Thread Standard Manual (Third Edition). Its representation method should be: ZG 3 /4″. Among them (〃) is the representative symbol for inches. One inch is equal to 8 inches. The origin of 3/4 is 6/8=3/4. Commonly known as 6 points. Similarly, the major diameter of ZG 1/2″ thread≈21 mm. Commonly known as 4 points. ZG 1″ thread diameter ≈ 33 mm. Commonly known as 1 inch. ZG 1 1/2″ thread pipe outer diameter ≈ 48 mm. Commonly known as 1 inch and a half. Taper pipe thread is very similar to pipe thread, the difference is Only in the taper. Note that the basic size of the pipe thread and ordinary thread is different. DN is the nominal diameter
Wood screws are similar to machine screws, but the thread on the screw is a special thread for wood screws, which can be directly screwed into wooden components (or parts) to connect a metal (or non-metal) part with a through hole to a wood screw. The components are fastened together. This connection is also a detachable connection.
Guangdong Yueluo Hardware Industry Co., Ltd. provides a screw positioning pin, which is composed of a main body part and an insert part. The main body part is a circular boss structure, and the bottom of the circular boss structure is provided with a rectangular groove. The inserting part is fixed on the middle part of the upper surface of the main body part, the lower part of the inserting part and the contact section of the main body part are in a circular truncated structure, the upper part of the inserting part is a cylindrical structure, and the outer surface of the cylindrical structure is provided with threads; the screw positioning pin , The structure is simple and the design is ingenious. The special structural design of the main part and the insert part can be positioned between the punch and the die in the first processing process, effectively reducing the gap formed during the processing between the punch and the die. Firmly fixed, suitable for the needs of large-scale industrial production.
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