A correct work can only be carried out perfectly with previously well-sharpened tools, so we must sharpen them frequently. The universal machines, in addition to other accessories, have various elements for sharpening, of different granulation and hardness. For the perfect polishing, special stones are usually used, which work perfectly.
Normal metal tools are sharpened with a carborundum disc. Hard metals, with one silicon carbide. For deburring and polishing, stones of different granulation, hardness and composition are used.
The gouges are usually hollowed out with specially shaped stones. There are also natural stones so that they can be sharpened with water or oil. There are also artificial stones that are preferably intended to be emptied with water or oil.
In the previous image, we can observe the honing without preliminary operation. This is only possible when the stone has a coarse grain. The rounded edges (eg, of the ax) are emptied by passing the stone over the blade. Sharpening and polishing constitute a single work process.
Before emptying wide blades (eg brush blade) the flatness of the disc must be checked. The rectification of said disc is done with another stone of greater hardness, pressing it evenly against it.
Sharpening a brush blade is done at an angle of approximately 25 °. Supporting it on the complementary accessory (see photo), it will move from one side to the other. It is recommended to check the angle of attack of the disc to optimize the process.
By checking with a pattern, it is possible to detect when a polishing stone is no longer useful. In the photo you can clearly see the deformation suffered in the center. The polishing movement is generally carried out on the entire surface of the stone, in order to avoid uneven wear of the stone and improve its durability.
After sharpening the blade will have to be polished. It will refine, therefore, on the wet stone, describing circular movements. In order to avoid accidents, the stone must be well embedded in a piece of wood.
The non-beveled side of the blade also generally has to be free of burrs. To do this, we recommend sliding the blade from one side to the other on the stone repeatedly, a movement that must alternate with the circular one, which has already been explained previously.
All the teeth of a circular saw blade must cut evenly, so the tips of the teeth must be the same distance from the axis. The depth adjuster of the attachment for sharpen saw blades ensures exact emptying.
Here is a video where an example of sharpening tools for carpentry is presented: