There are many types of screw connections in precision machinery and instruments. Commonly used are cylindrical head anti-theft screws, spherical cylindrical head screws and countersunk screws.
Cylinder head screws are one of the most widely used screws. Increasing the diameter of the screw head can increase the strength of the screw driver slot, and is suitable for the case where the connection needs to be frequently disassembled. In addition, the screw is tightened due to the corresponding increase in the bearing surface
When it is not easy to damage the surface of the connected parts. Therefore, it is generally possible to use a gasket and to apply a part made of a soft material such as a non-ferrous metal or an alloy thereof.
The spherical cylindrical head screw has a beautiful appearance, but the screw screw groove is weak in strength, and it is easy to be damaged when the tightening torque is large.
Hex heads and socket head cap screws are also commonly used when the load is large.
When the screw is on the outer surface of the instrument, it is best to use a countersunk head or a semi-sunk head screw. Among them, the semi-sunk head screw is more beautiful. In addition, since the nail head of the countersunk head screw is connected to the parts, it does not hinder the work of other parts. Therefore, the screw connection inside the instrument is also often used as a countersunk head screw. It should be noted that the countersunk head or the semi-sunk head screw itself has a positioning function.
Due to the large number of screw-connected parts and large size range, it can be selected according to the specific structure and size of the connected parts and design requirements.