A scraper is the next tool to be used on a surface after it is smoothly filed with the object of forming a plane; after it is thus filed, a scraper will make it still smoother, and after a smoothly polished scraper has been employed, the jagged projections made with the scraper must be smoothed by grinding and polishing. A scraper for making plane surfaces is denoted by Fig. 330 ; a tool of this class has only one cutting edge if the extremity is at about forty degrees with the length of the scraper, and has two cutting edges when the extremity is at right angles to the scraper's length. Fig. 331 indicates a scraper which is made of a three-sided file that has been used for sharpening saw-teeth and become too much worn for this purpose. When made into a scraper, the scraping part may be made to any precise shape the work may require, or the scraping part may be sharpened while still maintaining its three-cornered character. A three-cornered scraper is used for finishing curved holes, round holes, inner corners of a number of openings of various shapes, mouths of holes, and small plane surfaces. The scraper shown by Fig. 332 is adapted for large curved surfaces ; the cutting part of the tool is somewhat similar to a semi-cone, and is provided with a blunt curved point or end, and two cutting edges which are useful for scraping the curved surfaces of brasses, also bearers of other metals, whether of steel or of Babbitt's metal; scrapers of this form will scrape also the inner surfaces of lever bosses, wheel bosses, joint bosses, steam-cocks, and water-cocks. For the advantage of a free handling, scrapers are made of small files, or of other small steel which is only large enough for the purpose.