Scrapers

It has a sharp cutting edge which is obtained by grinding and sharpening processes on stones. They are used mostly on steel to produce a very precise finish on its surface that has been finished.

The following is the procedure of using scrapers.

1. Use a surface plate and a blue marking ink (Engineers Blue) to produce a flat surface.
2. Clean the surface place and smear a thin layer of ink on it.
3. Place the work on the surface plate and move back and forth.
4. Remove the work and colour the high spots.
5. Remove the high spots using a scraper and rub the work on the surface plate again.
6. Repeat the above steps until the work is as flat as possible.
7. Protect the cutting edges by properly storing them.

The following are the types of scrapers.

Flat Blade Scraper: It has a straight flat blade with a sharpened tip and is used to produce accurate flat surfaces. The tip is often slightly convex to help prevent the corners of the scraping surface causing burrs.

FIGURE

Triangular Blade or Three Corner Scraper: It has a long triangular blade that tapers to a point at the end and also have three scraping edges. They are commonly used to scrape awkward corners and the edges of flat surfaces and to remove burrs from the small bearings.

FIGURE

Curved Blade, Half Round or Bearing Scraper: It is used for scraping curved surfaces such as the inside of bearings and the other curved surfaces.

FIGURE