A circular saw is a steel disk with cutters applied on its edge and gaps between them - sinuses. They may appear as soldered alloys that are harder than the substrate, or cut from the shape of the case itself. The entire row of saw cutters is called a ring gear, and the disk is called a blade. The front surface of each tooth is the front face, and the back is called the back. The distance between adjacent vertices of the incisors is called a pitch. In standard saws, the entire ring gear consists of the same pitch and height. As a result of work, a hand-held circular saw leaves a cut in the wood - a gap limited by three edges.
Sharpening of a circular saw, as well as finishing its teeth with carbide tips, is carried out by means of abrasive (carborundum) wheels. The method can be combined: the first (rough) procedure is performed with abrasives, and the finishing one - with diamond tools. To preserve the carbide of the cutters and the properties of the grinding wheels, pre-treatment is carried out due to the length of the blade - along the back edge, and thin - along the front.
Sharpening of a circular saw on the reverse side consists in grinding the steel part of the cutter at an angle of α+6°. Thinthe carbide blade procedure uses an angle of α + 2°, finishing the part of the blade that is adjacent to the blade - an angle of α. The front edge is processed by preliminary sharpening along the entire length of the plate soldering, and the final one - along the front side (provided that the finishing method is used, which should be carried out with the participation of continuous cooling). However, for Bakelite-bonded diamond grinding wheels, it may be possible to sharpen the saw blade in normal mode.
On modern machines that use combined tools (two fractions of grains - diamonds with abrasives), sharpening is carried out with continuous cooling in one pass with the removal of the allowance by 0.25 mm. There are carbide saws that use plates with double-sided processing. Rearranging them, they work on both sides, then they are allowed to be processed to make new canvases. Such sharpening of the circular saw greatly simplifies the management of the tool economy due to the centralization and enlargement of the enterprises used.
If the disc back face of the tooth is made flat, and sharpening is carried out along it in parallel layers, as the cutter wears, its back angle becomes sharpened, and with a certain number of regrinds, it risks becoming unacceptably small.
Of course, you can process the tooth along the plane of the back strip, which will keep it tilted. But such a measure will lead to a decrease in the sharpening angle with a deliberate loss in the accuracy of the cutter. To ensure the stability of the slope,the back face is processed according to one of three options for laying curves: using the Archimedean spiral method, through a logarithmic spiral, or along an arc of a circle emanating from a displaced center. The last method is used to sharpen the widely used Interskol circular saw.
To maintain normal conditions for sharpening those sections along the contour of the tooth blade that are in the plane of rotation of the blade or are located close to it, arrange the angle of side clearance through the oblique side turning of the rear wall of the cutter (as in a conventional planer saw).
