Some agricultural machinery repairmen and agricultural machinery operators have taken the initiative to replace new parts with parts that are worn but still available, causing unnecessary waste. In order to save repair costs and promote "repair of old and waste," we must fully grasp the following repair methods so that the repaired parts are close to their original performance. 1. The transposition method utilizes the characteristics of non-uniform wear of the parts to flip or rotate the worn parts of the parts through an angle, and to align with parts that are not worn or where the wear is small, so that the worn parts can be used continuously. If the flywheel ring gear of the engine is turned over 180 degrees, it will work normally with the gear on the unworn side. This method is simple, and the repaired performance and quality are good. This method can be applied to eccentrically worn parts where the strength of the part is allowed and the structure is not limited. 2. The repaired size method will use the more expensive one of the worn fittings to restore its correct geometry by machining. The size of the machined part is called the repair size, and the other part that is matched with it is replaced with the new one. Such as the journal and bearing with a clearance of 0.06-0.118 mm, when the gap after wear exceeds the allowable value of 0.25 mm, the journal will be repaired according to the size of the repair grinding and then according to the size of the journal after dressing to increase the size Bearings. This method is simple, retains valuable parts and only replaces wearing parts. For holes, the repaired size is larger than the standard size; for the shaft, the repaired size is smaller than the standard size. 3. When the working part of the additional part method part has been seriously worn out and can no longer be used, if the construction allows, the worn part can be processed to the correct geometry; machining an additional part is fitted to the worn part to compensate and restore the original fitting. relationship. Such as the valve seat seat ring, inlaid cylinder liners, shaft or hole parts such as inserts. 4. Partial Part Replacement Method The difference between this method and the add-on part method is that instead of adding accessories, the damaged parts are partially replaced and repaired, that is, the worn parts of the parts are removed, and new welding repairs or rivets are made on the original parts to make repairs. Parts become complete available parts. If the gear is damaged by a few teeth and the rest of the teeth are intact, the trapezoidal groove can be milled on the machine tool tooth root and then the new tooth blank with the same groove shape can be pressed into the machined trapezoid. In the tank, it is fixed by welding or stabilizing nails, and then the tooth blank is processed and shaped. 5. Restoration size method This method is to add metal to the worn parts of the parts by plating, spraying, surfacing, etc., and after processing to restore the original size and shape. Specific methods are the following: (1) Mechanical bonding, that is, relying on the friction between the metal and the part to maintain the relative position and size, such as metal spraying, wire cracking, metal patch and so on. (2) Electrodeposition bonding, that is, deposition of metal on parts during plating, such as iron plating, chrome plating, and the like. (3) fusion bonding, that is, the surface of the part is melted at a high temperature, and is fused with the melted supplementary metal, such as electric welding, forging, and the like. (4) Adhesive bonding, that is, the use of adhesive bonding, such as chemical glue and so on.