what-is-an-engineer-s-scraper

What is an engineer’s scraper?

See prices for engineer’s scrapers
Selection of different engineers scrapers 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.

Engineers scraper in use 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?

Engine cylinder block from a V12 engine The most common examples of when a scraper would be used are:

  • When transferring the accuracy of one mating surface to another, such as on the cylinder block and cylinder head of a car engine
  • To achieve a flat surface for machine blocks, which will improve the accuracy of the machine when in use.

Why is it called a scraper?

Engineers scraper in use Engineer’s scrapers get their name from the action of scraping the surface of metal in order to perform their job.
Whilst the action of scraping only requires a scraper, the process of scraping to achieve a flat surface does require several other tools. To see what, have a look at the “how to use an engineers scraper” section.

Why use a scraper?

Surface being lapped 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

Paint scraper and engineers scraper comparison 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.
Tools that should not be used as an engineers scraper 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.

Sir Joseph Whitworth Wonkee Donkee says: "Engineers scrapers have been used since the industrial revolution (1760-1840). However their use did not become widespread until after the 1840 presentation of Sir Joseph Whitworths "Miscellaneous papers on mechanical subjects" to the British Association in Glasgow."