Bolt is one of the commonly used fasteners in machinery, usually composed of nuts and cylindrical threaded parts, which are connected to two perforated parts through rotation. There are various types and specifications of bolts, and common specifications on the market include M10, M12, M20, M22, M30, M42, etc. The weight and nut situation vary, and different specifications of bolts need to be selected for different machinery.
The types of bolts are mainly divided into the following categories:
1. Divided according to the connection force mode
According to the different stress modes of the connection, bolts are divided into ordinary bolts and bolts for reaming holes. Ordinary bolts are used to withstand axial forces, while bolts for reaming holes are commonly used to connect two parts with slots and can rotate freely.
2. Divided by head shape
The head shapes of bolts include hexagonal, square, round, and countersunk heads. Hexagonal heads are relatively common and are suitable for situations where a wrench or wrench is required for tightening.
3. According to the tooth shape of the thread
There are two main types of threads for bolts: coarse and fine, with varying pitches and angles. Coarse tooth bolts are suitable for situations with thicker materials or high cutting forces, while fine tooth bolts are suitable for machinery or equipment that require more precision.
4. Classified by performance level
The performance levels of bolts include 3.6, 4.8, 5.6, 5.8, 8.8, 9.8, 10.9, and 12.9, with high-strength bolts made of low-carbon alloy steel above 8.8 and ordinary bolts below 8.8. The tensile strength of bolts of different grades also varies.
5. Classified by production accuracy
The manufacturing accuracy of bolts is usually divided into three levels: A, B, and C. Among them, A and B are refined bolts, usually used for lathe processing, with a general performance level of 8.8, while C is a rough bolt with a performance level of only 4.8, commonly used for fixing temporary parts.
Overall, bolts of different types, specifications, and performance levels have their own characteristics. Choose appropriate bolts based on the needs of different machinery or equipment to achieve better tightening results.
