Fig. 119.
Scrapers may be pushed or pulled. [Fig. 120]. When properly sharpened thin silky shavings will be cut off. The cutting edge of a scraper is a bur which is formed at an arris and turned at very nearly a right angle to the surface of the scraper.
Fig. 120.
Fig. 121.
When a scraper becomes dull (1) each edge is drawfiled, [Fig. 121], so as to make it square and straight, with the corners slightly rounded. Sometimes the edges are rounded slightly from end to end to prevent digging. Frequently the scraper has its edges and surfaces ground square on an oilstone after the drawfiling that the arrises may be formed into smoother burs. (2) After filing, the scraper is laid flat on the bench and the arrises forced over as in [Fig. 122]. The tool used is called a burnisher; any smooth piece of steel would do. (3) Next, turn these arrises back over the side of the scraper. [Fig. 123]. Great pressure is not necessary to form the burs properly.
Fig. 122.