What is an engineer's scraper?
An engineer's scraper is a hand tool used to remove high spots from the surface of machined metal.
An engineer's scraper looks very similar to a file, but instead of having a large rough area to remove material, a scraper has a very sharp edge that is used to smooth high points.
|Scrapers are mainly used to eliminate high spots from flat surfaces in order to give a truer flat surface (although a truly flat surface can never be achieved).|
When would a scraper be used?
The most common examples of when a scraper would be used are:
Why is it called a scraper?
Engineer's scrapers get their name from the action of scraping the surface of metal in order to perform their job.
Why use a scraper?
Scraping has several advantages over other methods of removing high spots such as lapping or grinding.
Scraping can be applied to high spots in just one particular area if needed. It is also the only way of transferring the accuracy of one mating surface to another, and, unlike grinding, does not stress or heat the metal workpiece.
Engineer's scrapers vs. other scrapers
The blade of an engineer's scraper is harder and thicker than that of a paint or glass and tile scraper. The heat treating and tempering process that an engineer's scraper undergoes gives it the superior hardness required for scraping the surface of metal, and the thicker blade helps provide strength to stop it from breaking during use.
A paint scraper would be too thin and not hard enough to scrape a metal surface.
A chisel has the wrong cutting angle and would dig into the surface of a workpiece, instead of skimming the surface and only taking off the high spots.