How to Choose a Circular Saw Disc
The circular saw blade is a working tool for cutting various materials. It is an integral part, without which it is impossible to carry out any operations on processing blanks. Saw blades are used in stationary machines and hand cutting tools.
Depending on the type of disk can be processed:
- Wood of various species;
- Wood products. Particleboard, OSB, plywood, laminated flooring and other similar materials;
- Polymeric substances and articles thereof, for example, organic glass, polystyrene;
- Natural stone material, such as marble;
- Soft metals. Aluminum, copper alloys;
- Products based on iron alloys. Pipes, corrugated sheets, etc.
The cutting tool has certain characteristics, parameters, sizes, purpose, properties of the material from which it is made.
Key parameters of circular saw blade
Outer (outer) diameter
Determined by the inner size of the protective cover. A disk with a large diameter does not fit on a saw with a smaller casing. The main dimensions of the cutting tool for hand-held circular saws are in the range of 130-250 mm. The outer diameter does not significantly affect the cutting speed, but determines the depth of cut. With an increase in cut, the engine is significantly loaded, the metal of the disk and the workpiece itself are heated.
Inner Rim Diameter
It has several sizes: 16, 20, 22, 30, 32. An important parameter. The diameter should correspond to the size of the power shaft on the saw, under which the disc is selected. Some disc models have additional holes that secure the disc to the pins.
The number of teeth on the disk
Affects parameters such as cutting speed and purity of processing. With a decrease in the number of teeth, the processing speed increases, the conditions for removal of chips are improved, but the purity of the cut decreases. With an increase in the number of teeth, the cut is cleaner, but the load on the engine increases. Conventionally, by the quantitative ratio, disks can be divided into three groups:
- A large number of incisors, is in the range of 80-90 pcs.;
- Average amount (40-80 pcs.);
- Small amount (10-40 teeth).
Disks with an average number of incisors are classified as universal. They can process soft and hard wood, perform transverse and longitudinal cuts, and use them for processing various wood products.
It is determined by the deviation from the radius of the disk surface of the cutting edge. With a deviation to the back of the tooth, the slope is called negative, with the reverse side of the slope. Positive. For longitudinal sawing, it is more advisable to use a tooth with a positive slope, since in the process of processing a peculiar grip of the material takes place, the disk hits the part, which contributes to a faster cutting of the workpiece as a whole. The inclination of the tooth is divided into:
- Standard tilt. The angle varies from 5 ° to 15 °;
- Positive, aggressive slope is 15-20 °;
- The usual negative angle is in the range of 0 ° to 5 °.
Each type of cutter is designed and made to solve a specific problem. Subdivided:
- Flat cutter. Used for fast longitudinal sawing of soft or hard wood, has the FT designation.
- Interchangeable cutter. Has a successively alternating interchangeable tilt of the teeth into one or the other side. Cutters give an even and fairly clean cut. It is used for transverse and longitudinal cutting of wood, processing plywood, OSB, chipboard and composite boards, marked with the symbol ATB.
- A combination cutter is a sequential change of groups consisting of a combination of four interchangeable cutters (ATB) and one flat (FT). Designated as Combi. This type of disk is classified as universal because of the ability to perform different types of cuts.
- Trapezoidal flat cutter. Made of successive flat teeth. Higher sharpened under the trapezoid, low is flat. It is used for processing wood and wood products, for polymeric materials and soft non-ferrous metals. Has the designation TCG.
- Replaceable cutter with an increased inclined side part. Designed for processing material prone to splitting, as well as for fine cross cutting. It is designated HiATB.
Determines the actual cut width.The standard size is 3.2 mm. In addition, the thickness of the disc affects the strength of the cutting tool itself. Decreasing the parameter leads to heavy operation, overheating of the disk and damage. A larger size causes an increased consumption of the processed material, that is, “transfer to chips”.
Circular saws are used in the processing of various materials. Accordingly, the cutting tool is performed for specific tasks.
Types of circular saw blades
Monolithic disk. They are made of high quality high carbon or high speed steel. They are used for processing wood and its products, as well as for cutting polymer products. They have several advantages:
- Simple sharpening of teeth. You can perform this operation yourself, without the presence of complex special devices;
- Repeatedly re-sharpened, therefore, have a sufficiently large resource of work.
A disc with teeth that are reinforced with carbide brazing. The canvas is made of durable tool steel. Brazing are alloys made of steel with a high content of tungsten or cobalt carbides. Thanks to this solution, these discs have become the most common. They have a number of advantages:
- Allow you to cut most of the known materials;
- No tooth bite required;
- Strong and reliable in the process;
- Service life from sharpening to sharpening several times higher than a monolithic disk;
- Give a cleaner cut;
- Increase cutting speed;
- Are available in a wide range to solve all kinds of tasks when cutting materials.
There is a significant drawback. Such discs are relatively expensive and special equipment is required for sharpening.
Disc Selection Guidelines
When choosing a disc, the technical parameters of the circular saw must be taken into account:
- Engine power;
- Maximum speed;
- Landing size on the motor shaft;
- Inner diameter of the protective cover.
Engine power affects the type of disc. Negative angle, a large number of teeth create a large load on the engine, which will have to work in “peak” mode.
The number of revolutions or the speed of rotation of the spindle are interconnected with certain disk sizes, which are recommended by the manufacturer. Installing a cutting tool with deviations from the recommended ones can lead to an abnormal mode of operation, as a result of which damage to the blade, saw and damage to the processed material are possible.
The landing dimensions of the blade (inner diameter) and the corresponding ones on the motor shaft must match, otherwise the tool cannot be installed on the saw.
The external size of the disk cannot exceed the internal size of the casing. If this parameter is violated, the tool will not be installed on the saw.
The type of disk is affected by a number of factors:
- Type of work performed, material being processed;
- Device, design of the cutting tool;
- Number of teeth, their design.
Work performed and material being processed. Since the disks are produced differently, it is necessary to determine the types of operations (what types of cuts will be carried out), and also take into account what the cutting tool will process.
Depending on the type of operations and material, the type of disk is selected: monolithic or with carbide brazing.
The processing mode and type of material determine the number of teeth, their type and inclination. The most popular is the average number of teeth with a trapezoidal sharpening with a positive angle of inclination.
There are several signs by which you can almost accurately determine whether the product is of high quality or made “on the knee”:
- Marking must be carried out on the disc, and the inscription is applied using a laser tool, not paint.
- The canvas should be subjected to grinding and polishing. The cleanliness of the processing is visible by looking if you play with the disc in the light.
- The cutting tool disc is subjected to balancing and calibration procedures. The operation conditionally resembles the balancing of a car wheel. After such processing, the cutting tool will not “beat”, and vibration will not occur during operation.
- To compensate for possible temperature expansion, special slots are made on the disk, ending with small discharge holes.
- Some manufacturers reinforce the disc with several circular stiffening rings.
- Another indicator of quality is the name of the manufacturer, his brand. Today it is European, American, South Asian, Russian and Chinese manufacturers (listed in descending order of quality). By the way, some Russian manufacturers produce products that are comparable in some respects with European or American.
In general, choosing the right circular saw blade is almost a science. If there is no experience, then it is better to consult professionals, and those who have the skill of working on a circular saw for at least 2-3 years.