The matching relationship between the hole and the shaft in the mold is divided into three types. The matching of the diameter of the hole larger than the diameter of the shaft is called the clearance fit. The matching of the diameter of the hole smaller than the diameter of the shaft is called the interference fit, and the diameter tolerance of the hole may be larger than the axis. The diameter of the shaft may also be smaller than the diameter of the shaft. This fit is called a transition fit.
In these three kinds of cooperation, the hole and the shaft are inactive after the interference fit. Obviously, the chrome bar guide sleeve will not be the fit mode, and the transition fit is required to form the tightness under the action of external force, for example, the pin pin is fixed. However, it is obvious that this method is not the way to guide the guide bush. When the clearance is matched, the hole and the shaft can move with each other, and the level of the slip fit is also achieved.