Dowel pins are very common to mechanical designers, and they are very useful. Let’s first introduce dowel pins. Dowel pins are actually an informal name. The strict name is Pins are connected components used to precisely limit the position and coordinates of parts, usually only two components that need to be matched will need to be added.

The dowel pin also has a second function, which is to replace and install the parts that have precise position requirements, and those that are replaced more frequently (some are called wearing parts) must be quickly replaced and installed. If there is no dowel pin, then It’s quite a hassle to find the original location.

Dowel pins can be divided into many types according to their classification. Since they are said to be pins, they are generally round and have a diameter of the main body. It can be divided into many types, for example: one end is round, the other end has screw teeth, this is a guide pin, which is commonly used for two parts that are often separated and combined. It is difficult to ensure that the pins can all fit in.

This kind of conical pin can be used, the head is also round, but it is relatively small, and it is easy to make the hole misaligned. Some products have a larger diameter than the bottom, and the bottom is smaller than the top. There are even A small flange is added in the middle. The difference in shape can be applied to different occasions, but there is one purpose, that is, the two parts are often clutched.

Let’s talk about its tolerances. Normal pins have a connection function, and tolerances can be set according to requirements. There are three types of fit, one is clearance fit, which means that no matter how big the hole is, the shaft can be easily inserted. It can even be slidable, and some people call it a sliding fit.