A scraper is a tool for scraping which is provided with at least one cutting edge . The negative rake angle of the cutting edge is characteristic, which distinguishes the scraper from tools for cutting.
A scraper can be any core stone , chips or a blade made of flint with a retouched (according to the morphological typology of F. Bordes) on the lateral side. In contrast, scratches have a convex retouching at the distal end.
The cuts of the rubble tools , as well as almost every cut or tool with a sharp edge, are suitable for scraping. The scrapers achieved the greatest distribution and variety of forms during the Middle Paleolithic . Usually they are made from tees, less often from blades. Scrapers have a flat effect as a cutting tool, but they can also be used with a linear effect. They can be used for smoothing or chopping wood, depilating or cleaning skins, cutting meat or vegetables, and scraping grooves in ivory , antlers , bones and stone. With angle scrapers, two edges meet at right angles . He may have had a special function. For a potential shaft, see: shaft (prehistory and early history) .
Scrapers are to be distinguished
- according to the manufacturing technique in:
- Chipping, blade, core (block), disc scraper;
- after the retouched scraping edge in:
- Head, bow, round, side, double-sided or book scraper ;
- During the manufacture of blades, core stones remained, which are known as:
- Core scraper (also called planer, high, keel or block scraper).
Keel scrapers were made from smaller stones, with their broad side drawn over the surface to be worked on. Hollow scrapers have a concave underside. Bow or straight scrapers with back processing are called back knives . It can be assumed that part of the scraper scarfed was. In the Ahrensburg culture one found scrapers made of organic material; Reindeer shoulder blades and minor vertebrae.
Even today, scrapers in very different shapes still have a fixed place in various branches of trade . In the goldsmith's trade , scrapers are used to adjust gemstone settings and to smooth surfaces. The scraper was named after the printmaking for the mezzotint . There, the scraper, together with the polishing steel, is used to design the image of the printing plate by enabling a sliding halftone scale from rich black to pure white.
In mechanics , scrapers are used to level metal surfaces. Plain bearing surfaces and slideways on machine tools are scraped. In the pockets, which are only a few thousandths to hundredths of a millimeter deep, there is space for lubricant, which means that there is sufficient lubrication even with high surface pressure.
Typical forms in the metalworking trade are the flat scraper and the triangular hollow scraper .
- ^ The large lexicon of graphics: artists, techniques, information for collectors , Westermann Verlag, Braunschweig 1984. ISBN 3-14-509079-8 (p. 33)
- Stefan Unser: The flint technology of the Stone Age. Schillinger, Freiburg 1983, ISBN 3-921340-88-8 .
- François Bordes: Hand ax and mammoth - The Paleolithic. Kindler, Munich 1968.