Drills are known to dull over time. Many simply throw them out and buy new ones. However, with a truly masterful approach to any business, you can also drill a drill to give a second life. And competently to sharpen a drill on metal it is possible and in house conditions, without application of any "high technologies".
At home, for household needs, drills of small diameters are generally used, usually no more than 16 mm. That's about sharpening such small drills and there will be a conversation. The best way is to process the drill on the grinding wheel. Every self-respecting owner in the garage has a grindstone. If not, then the second option is to fix the electric drill, the grinder( which is available).For us it is necessary one thing - to get a rotating grindstone( disk).
As a "cooler" you can use water, engine oil. If the drill is not periodically immersed in the coolant, it will overheat and will not be able to withstand the necessary load and temperature conditions while drilling. In other words, such a drill will not serve for a long time.
The process of sharpening the drill bit
Drill sharpening is carried out in sequence - first the back surface is processed. You need to do this carefully, in several ways. The drill must be pressed firmly against the surface of the grinding wheel. It is necessary to pay attention to the angle of sharpening, it should be unchanged. As a result of the processing of the back surface, the correct cone should be obtained if one looks at the tip of the drill from the side.
The cutter part of the drill is then machined. It is also necessary to strictly maintain the angle. And only after this operation is already final finishing of the back surface. It is necessary to monitor the jumper, it is located at the very tip of the drill. If the drill is properly machined, its size should not exceed 0.4 mm for drills with a diameter of 8 mm or less. If the drill is larger, the size of the jumper can be in the range from 1 to 1.5 mm.
Do not be discouraged if you do not get it right away - such work is given only with time. It is best to practice on some other before starting to sharpen the required drill. In the economy, for sure, there are several pieces that have long been "out of order" and just lying around among the trash.
The main thing is to get the drill processing skill on the emery, to feel how to press, how to "hold" the angle. If a sharpened "exhibit" is inserted into the drill and started drilling, it immediately becomes clear what error was made when sharpening.
It should be borne in mind that the drilling is performed not by the tip itself, but by the sides of the drill. Many make the mistake of trying to sharpen only one end of the drill, not paying attention to the side edges. To sharpen drills with a winning tip, there is a somewhat different technique, more complicated.
Video from the master - sharpening of drills:
