How to sharpen a circular saw at home

Sharpening the saw blades yourself

The saw blade on my Makita 2704 is dull. There is no finance to buy a disk from Makita or SMT at the moment.

Using water for cooling can lead to rust on machine parts and components. To eliminate corrosion, water and soap are added to the water, as well as some electrolytes (sodium carbonate, soda ash, trisodium phosphate, sodium nitrite, sodium silicate, etc.), which form protective films. For normal grinding, soap and soda solutions are most often used, as well as for fine grinding, low-concentration emulsions.

However, when grinding saw blades at home with a low intensity of grinding work, the wheel does not resort to cooling very often, not wanting to waste time on it.

To increase the grinding ability of abrasive discs and reduce specific wear, select the largest grain size that provides the required surface cleanliness of the sharpened tooth.

sharpen, circular, home

To select the grit size of the abrasive according to the grinding stage, you can use the table in the article on grinding rods. For example, if you are using diamond discs, you can use 160/125 grit discs for roughing, or 125/100 grit discs for finishing. 63/50 or 50/40. Wheels with grit sizes from 40/28 to 14/10 are used to remove teeth.

The peripheral speed of the wheel when sharpening carbide teeth should be about 10-18 m / s. This means that when using a circle with a diameter of 125 mm, the engine speed should be around 1500-2700 rpm. brittle alloys are sharpened at a lower speed from this range. When sharpening carbide tools, the use of hard mods leads to the formation of increased stresses and cracks, and sometimes to grinding of the cutting edges, while the wear of the wheel increases.

When using grinding machines with a saw, changing the relative position of the saw and the grinding wheel can be done in different ways. by moving one saw (the motor with the wheel is stationary), while moving the saw and the motor, only the motor with the wheel is moving (the saw blade is stationary).

sharpen, circular, home

A large number of grinders of various functions are produced. The most complex and expensive programmable complexes are capable of providing a fully automatic grinding mode, in which all operations are performed without the participation of a worker.

In the simplest and cheapest models, after installing and fixing the saw in a position that provides the required sharpening angle, all further operations rotate the saw around its axis (turning the tooth), feeding it for grinding (bringing it into contact with the wheel) and controlling the thickness of the saw metal. are made by hand. It is advisable to use such simple models at home when the sharpening of circular saws is episodic.

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An example of the simplest machine for circular saw blades is the system shown in the photograph below. It consists of two main blocks. motor with circle (1) and support (2) on which the sharpened saw is installed. The rotating mechanism (3) is used to change the blade angle (when sharpening teeth). The screw (4) moves the saw along the axis of the abrasive wheel. This ensures that the set value for the front grinding angle is set. The screw (5) is used to set the stopper in the desired position, preventing excessive penetration of the circle into the interdental cavity.

Sharpening quality control

GOST 9769-79 establishes certain values ​​of tolerances for sharpening parameters. The face runout of the tops of the teeth should not exceed 0.2 mm (for saws with a diameter of up to four hundred mm), radial. 0.15 mm. The beating is checked using a conventional dial gauge.

The deviations of the sharpening angles should not exceed:

HOW TO SHARPEN CIRCULAR SAW BLADES, SIMPLE JIG.

  • for the front corner. ± 1 ° 30 ‘;
  • for the back angle and bevel angles of the front and rear planes. ± 2 °;

How to Sharpen a Circular Saw at Home

How to sharpen a circular saw correctly?

Saw blade grinding is possible both with a special machine and with improvised tools.

You can sharpen a circular saw yourself, if you follow the instructions, then there is nothing particularly difficult about this.

It should be borne in mind that all circular saws need correct and timely sharpening, but those that do not have high power must be sharpened carefully. The point is that a dull disc helps increase the load on the electric motor. This is the result of the fact that it quickly overheats, and it becomes impossible to work with the tool, as it breaks.

A saw blade needs urgent sharpening if it has the following characteristics:

  • You need to make a lot of effort when cutting.
  • Cutting edges start to burn, foul odor and dark spots from saw teeth.
  • The protective cover of the heater begins to heat up very quickly (even when using such a tool, smoke may appear).

Sharpen Circular Saw Blades with Trend | Toolstop Guide

Saw sharpening

How to sharpen your circular saw blades, the easy way.

In the process of work, the saw teeth become dull, the cutting front and side edges are rounded, the saw stroke becomes heavy and you have to press hard on it. Experienced craftsmen can easily determine the sharpness of the saw by the brilliance of the cutting edges and tops of the teeth and by the sound of the saw. To restore the cutting ability of the teeth, they are sharpened with files or file files, giving them sharpness and maintaining their parameters: angles, steps and heights.

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Saw teeth sharpening. a kind of art that requires loyalty of hands, a good eye, attention. It is not difficult to learn this business, you must have the desire and clearly adhere to the following rules:

  • The saw blade must be firmly fixed in a special device made of wood, which is also firmly installed on a well-lit work table. Sharpening saw teeth on stools or on your knees does not give a satisfactory result.
  • You should use a personal file, followed by cleaning the sharpened edges of the teeth with a velvet (with a fine notch) or file. It is desirable that the file is new, sharp and with a fitted handle. If at the right moment there was not one, then you can also use a second-hand one, but always brushed with a steel brush and rubbed with charcoal so that the file does not get clogged and does not become dull. When sharpening a tooth, the file should grip its metal and remove its layer depending on the pressure. And if it slides over the tooth without removing the metal, then the saw teeth are overheated or the file is worn out. In this case, it is necessary to repeat the sharpening with a new file. If in this case he slips over the tooth, then it remains to take another saw.
  • The file handle is clamped with the right hand, and the end of it is held by the left hand and the file is directed to the saw teeth. Working with a file, depending on the type of saw, is described below.
  • The pressure of the file on the teeth should be smooth and even and only to one side from you. When returning the file to its original position, it must not touch the teeth.
  • It is necessary to try to grind the metal from the edges of the teeth of at least the same thickness, driving the file the same number of times with the same pressure, which allows you to keep the angles, pitch and height of the teeth after sharpening.
  • Burrs are formed on the edges of the tooth from the side of the file exit, which reduce the sharpness of the tooth, and if they are not removed, then during the operation of the saw they crumble, and the teeth become significantly dull. To remove burrs, the edges of the teeth are sharpened with a file with a velvet notch and deburred from the side edges with a wet donkey.
  • After sharpening the teeth, check their sharpness. Look at the tip of the needle and the edge of the razor blade: they are sharp and do not shine in the light. And if they are blunt, then rounded surfaces appear at the tip of the needle and on the edge of the blade, which reflect light and shine well. The quality control of saw teeth sharpening is based on this principle. To do this, put the saw in front of your eyes and examine its teeth along the blade. If their cutting edges and tops are not shiny, then the saw teeth are sharpened satisfactorily, and if some of the teeth are shiny (this often happens), then they must be sharpened with a velvet file, deburred and re-check the light reflection from their edges and tops.
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Cross saws. The teeth of the cross-cut saws are sharpened using a triangular file with a fine notch with a 60 ° point angle.

To sharpen the teeth, the saw is clamped into a special device that allows its blade to be installed at an angle of 45-50 ° to the plane of the desktop. The file is led parallel to the working table at an angle of 60-75 ° to the saw blade and thus the left edge A1 A2 B2 B1 is sharpened in the first tooth.

Crosscut saw sharpening: 1. saw blade; 2. a sharpened tooth; 4. device for sharpening; 5. working table for sharpening saws; 6, 8. directions of the file 7 in relation to the working table and the sharpened saw teeth; 9.the line of the bend of the teeth when they are set

Saw teeth are sharpened in several stages. First, with a file, they pass along the left edges of the odd teeth located in the far row, adjusting the hands to the same movement. Then they pass the file along the right edges of the same odd teeth, completing the sharpening of the main cutting edges with very sharp tops. After finishing the sharpening of the odd teeth, the saw blade in the sharpening device is turned over and thus the even teeth that are in the far row are sharpened. When sharpening the teeth of cross-cut saws, it is necessary to carefully ensure that sharp main cutting edges with a dihedral angle φ = 60-75 °, a short cutting edge and a sharp point are obtained in each tooth.

Rip saws. Rip saw teeth, in which the angle