The scraper is the main tool for scraping, and T12A high carbon tool steel is generally used to make the scraper. According to the scraping surface of the workpiece, scrapers can be divided into three categories: flat scrapers, triangular scrapers and crescent-shaped scrapers. The flat scraper is mainly used to scrape planes, such as flat plates, flat rails, workbenches, etc., and can also be used to scrape outer curved surfaces; the triangular scraper is one of the commonly used tools for scraping bearing bushes; the crescent-shaped scraper is mainly used to scrape inner curved surfaces, such as movable bearing bore etc. The scraper is the main tool for scraping, and the quality of the scraper is an important factor that determines the efficiency and quality of side scraping. Therefore, attention should be paid to the correct selection and sharpening of the auxiliary knife when scraping.
It is better to use T12A high-carbon tool steel as the material of the auxiliary knife, and the hardness after quenching is RC60~65. For the purpose of saving, medium carbon steel can be used as the blade body, and a high carbon steel blade head is welded in front.
There are also scrapers made of high-speed steel. This kind of auxiliary knife has good wear resistance, but it is difficult to sharpen and the edge of the knife is not easy to polish. Generally, it is rarely used.
In some cases, due to material limitations, scrap saw blades on sawing machines, or thin disc milling blades can be used as the cutter head, and welded on the cutter body to make the auxiliary cutter. A spatula can also be made from an old file. The file has teeth and is prone to cracks during the forging process. Therefore, the teeth of the file should be ground before forging to prevent cracks from forging. Or directly annealed with a file, planed or ground to the required size. When forging scrapers with ready-made materials, care should also be taken not to produce cracks, and scrapers with cracks cannot be used.
