What is Hand Scraper?
A hand scraper is a single-edged tool used to scrape metal from a surface. This may be required where a surface needs to be trued, corrected for fit to a mating part, needs to retain oil (usually on a freshly ground surface), or to give a decorative finish.
Surface plates were traditionally made by scraping. Three raw (plates that have been `seasoned` or residual stress relieved and received suitable surface treatments, but unfinished) cast surface plates, a flat scraper, and a quantity of bearing blue (or red lead) were all that was required in the way of tools.
The scraper in the center of the image is a three-corner scraper and is typically used to deburr holes or the internal surface of bush-type bearings. Bushes are typically made from bronze or white metal.
The scraper pictured at the bottom is a curved scraper. It has a slight curve in its profile and is also suitable for bush bearings, typically the longer ones.
One advantage of scraping is the ability to take the tool to the workpiece, this can be useful when the workpiece weighs several tons and is difficult to move.
Types of Scrapers Tools
There are following types of scrapers tools are used and their uses are described below in detail.
- Flat Scraper
- Curved Blade Scraper
- Three Square Scraper
- Bullnose Scraper
- Two Handle Scraper
- Hook Scraper
1. Flat Scraper
A flat blade scraper consists of a straight flat blade with a sharpened tip end for scraping. This type of scraper can only be used on flat surfaces but is the most efficient scraper for this job. The sharpened scraping tip is often slightly convex to help prevent the corners of the scraping surface from causing burrs.
2. Half Round Scraper
Also called ‘bearing scrapers’ or ‘half-round scrapers’, as they’re used for scraping the inside of bearings and other curved surfaces to achieve a better mating surface, curved blade scrapers have two sharp edges.
3. Triangular Blade Scraper
Sometimes referred to as ‘three corner scrapers’, these scrapers have a long triangular blade that tapers to a point at the end. They also have three sharp scraping edges and can be used on both flat and curved surfaces.
These types of scrapers are mainly used to scrape into corners and the edges of flat surfaces or to remove burrs from the inside of small bearings.
4. Bullnose Scraper
The shape of these types of scrapers is similar to the shape of the nostrils of a bull, so it is called a bullnose scraper. It is used for scraping flat and half-round surfaces. Its edge is found in a circular disc, and it is in 2/3 of the circle. It is helpful in scraping large size bearings.
For this, the large bearing surface is scraped by longitudinal stroke or with circumferential movement.
5. Two Handle Scraper
It is used to scrape large flat surfaces and also used to scrap large curved surfaces.
6. Hook Scraper
Its shape is like a flat scraper, but its point is bent at an angle of 90 °. Therefore, where a flat scraper cannot be used, it is used. Apart from this, it is also used for scraping the central part of large flat surfaces. It is often used for finishing work.
7. Diamond scrapers
Diamond scrapers were a staple of a basic turning setup until the 1980s. The street view is that a diamond scraper is for incising lines in work, but its real purpose is to make exact fits in box lids, chucking recesses, jam chucks, tenons, and the like.
I call it a “chuck making scraper.” The edges of this scraper are 90˚ to each other, which is great for box lids, but they are reground to less than 90˚ for inside holds for most four-jaw chucks or more than 90˚ for outside holds.