Hand scraping is considered a lost art among machinists, who in the modern age rely on mechanical methods to get a flat surface. The need for flat surfaces in the past have resulted in the required skill of hand scraping cast iron and metal surfaces, as a flat surface is the basis of a truly accurate and precise system. Does this Spark an idea?
Instructions
1. Sharpen your hand scraper. Making sure to maintain the angle of the bevel, the hand scraper must be sharpened and honed and kept sharp throughout the entire process.
2. Apply layout dye to the first cast-iron plate. The layout dye must be spread in a thin layer to prevent false information on the location of high spots on the surface plate. If layout dye is not available, blue Prussian oil paint can be used in thin layers.
3. If using a test standard, rub the standard in an even and flat manner all over the surface. What should remain are spots where there is no longer any layout dye. If you do not have a flat test surface, use the second plate instead.
4. Holding the blade at a shallow angle, lightly scrape at the surface of the plate only where the dye was rubbed off. These spots represent the highest spots of the cast-iron plate.
5. Once every spot has been scraped, clean off remaining dye and repeat, using the same plate as the test plate. Continue repeating until the dye comes off cleanly, indicating a flat surface.
6. If you are using three plates, once the first is done, start on the second with the third as test and then the third with the first as test. Repeat the cycle, and you should be left with three testworthy flat plates.
Tags: flat surface, cast-iron plate, hand scraper, plate layout, surface plate
