What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
ANSI B1.1 Thread Pitch Comparison Table Nominal Diameter (inch〖mm〗) Coarse Thread Pitch (UNC) Fine Thread Pitch (UNF) Ultra Fine Thread Pitch (UNEF) Drilling Diameter (Coarse Thread) Drilling Diameter (Fine Thread) #0 0.060 〖1.524〗 80 1.2 # 1 0.073 〖1.5 1.5 # 2 0.086 〖2.8 # 3 0.099 〖2.515〗 48 56 2.0 2.1 # 4 0.112 〖2.4 # 5 0.125 〖 3.175〗 40 44 2.5 2.6 # 6 0.138 〖3.50〗 32 40 2.7 2.9 # 8 0.164 〖4.166〗 32 36 3.4 3.5 # 10 0.190 〖4.0 # 12 0.216 〖5.486〗 24 28 32 4.5 4.6 1/4 6.35 20 28 32 5.1 5.4 5/16 10.7 11.5 9/16 〖14.288〗 12 18 24 12.3 13.1 5/8 〖15.875〗 11 18 24 13.5 14.7 3/4 〖19.05〗 10 16 20 16.7 17.5 7/8 〖22.125 2.4 9 14 〗 8 12 20 22.2 23.4 The pitch is expressed by the number of teeth per inch, such as: 11 teeth per inch, then the pitch=25.4/11=2.309mm. The unit of pitch in the table is the number of threads per inch. The hole diameter is the recommended hole size for tapping, in millimeters.
Existing bolt and nut connections usually use threads for connection, and this connection method has two main drawbacks. First, tools are required to be used to lock it during installation, and it takes a long time to complete, which is time-consuming and labor-intensive; Second, the installed bolts and nuts are prone to loosening after a period of time, resulting in loosening and shaking between the connecting parts. Therefore, there is a need for a bolt and nut fastener that is easy to install and can effectively prevent the loose fit of the bolt and nut, so as to solve the problems existing in the prior art.
With the improvement of living standards, people's requirements for the comfort of sitting and bedding are gradually increasing. Independent pocket spring cushions have moderate hardness and are generally welcomed by people.
It is used for fastening in the machinery, construction and electrical industries. One end is a hexagonal head for wrench tightening, and the other end is a thread. According to different thread lengths, it is divided into full thread and half thread, abbreviated as: GB bolt.
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