What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The production of non-standard round flat pads can only be processed on ordinary lathes without punching machines. Processing with round steel is difficult, material waste is large, tool loss is large, and efficiency is low. The purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a non-standard circular flat pad lathe processing fixture, which is suitable for the production of various non-standard circular flat pads. Yueluo is realized in this way. It includes a hollow square support, a bolt and a circular machining groove. It is characterized in that a circular machining groove is left on one surface of the hollow square support. There are 4 bolts evenly connected. The advantages of Yueluo are: 1. Reduce the difficulty of processing; 2. Save materials (can use corner waste); 3. Reduce tool wear; 4. Improve production efficiency.
Thread Code Broadcast Coarse Thread Series UNC Fine Thread Series UNF Extra Fine Thread Series UNEF Fixed Pitch Series UN Marking Method Broadcast Marking Method: Thread Diameter - Number of Threads per Inch Serial Code - Accuracy Grade Example: Coarse Thread Series 3/8—16 UNC— 2A Fine pitch series 3/8—24 UNF—2A Extra fine pitch series 3/8—32 UNEF—2A Fixed pitch series 3/8—20 UN—2A The first digit 3/8 indicates the outer diameter of the thread, in inches , to convert to metric unit mm, multiply by 25.4, that is, 3/8×25.4=9.525mm; the second and third digits 16, 24, 32, 20 are the number of teeth per inch (the number of teeth on the 25.4mm length); The text code UNC, UNF, UNEF, UN after the third digit is the series code, and the last two digits 2A are the precision grade. UNC: Unified Coarse Thread.
As shown in FIG. 1 and FIG. 2 , a rivet die in the prior art includes a set of top die 1 and cover die 2 arranged opposite to each other. The top die 1 is provided with a cavity 1 in the center that matches the shape of the rivet dome head 3-1. -1, the center of the cover mold 2 is provided with a mold cavity 2-1 that matches the shape of the rivet dome head 3-3.
Fasteners are widely used in nuclear power plant safety systems and equipment, and undertake the functions of component connection, pressure sealing box support and fixation, and their quality and performance play an important role in nuclear power plant safety systems and equipment performing nuclear safety functions. None of the special fasteners for nuclear power in the prior art have protective sleeves, which cannot protect the exposed part of the bolt shank. In order to solve the above difficulties, it is necessary to develop a fastener stud nut washer set that can protect the exposed part of the bolt shank.
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