As you master the skill of making precise and accurate cuts with a circular saw, start by choosing a good blade. Correct work equipment will allow you to cut various materials efficiently and quickly, reduce waste losses and minimize the risk of injury.
All-metal discs are already rare, although they have proven themselves well earlier in amateur workshops. They blunt quickly, however, they are easy to sharpen on their own, and they can withstand a lot of regrinding. Carbide-tipped saw blades are more expensive and harder to rebuild. But they “walk” longer, cut better and justify the money spent before replacing them with new ones, even without sharpening.
Remember the characteristics of your instrument
Start choosing a blade by looking at the technical features of the circular saw , remembering three indicators:
- Fitting size – the diameter of the power shaft corresponding to the inner hole of the saw blade.
- The permissible outer diameter of the working nozzle, limited by the size of the protective cover.
- The spindle rotation speed is a value set by the manufacturer, always less than the maximum possible number of revolutions for the disc being used.
It is permissible to put a disc with a “non-native” fit through an adapter ring, which is sometimes present in the kit. A smaller outer diameter can be used, taking into account the reduction in the depth of cut. Locating pins found on the spindle of some models require a disc with appropriate through holes.
Read the label
Knowing the basic characteristics of the circular, study the information from the package. It must indicate the permissible rotational speed, external and landing dimensions. Drawn pictograms can represent the intended materials, indicate the direction of the cut, and much more.
Advice. A manufacturer that respects the consumer applies enough markings to the disc blade by means of laser engraving. An unmarked product raises the question: what is it and why is it made?
Look at the prongs
The number of teeth is the main feature that determines the purpose of the saw blade and, in many respects, its cost. Blades with a small number of teeth are characterized by high cutting speeds and a “dirty” cut that requires further processing. The tooling with a large number of picks is recommended for sawing hard materials and for finishing cuts.
Circular saw blades differ from equipment for pendulum saws in the inclination of the teeth, which is explained by the different trajectory of movement of the working part in the workpiece. Discs with a negative or neutral angle of inclination used on the bevels press on the surface from above and cut the material, while the cut part rests against the limiter and the disc does not retrack into it. When installed in a circular machine, such a circle will repel the workpiece, clog up with sawdust and overheat the engine – it is very difficult to make a longitudinal cut with it, especially in undried wood. Used for circular saws, “positive” discs have teeth directed at an angle to the surface and shears the material like a planer knife, pulling the wood underneath.
Useful information about the purpose of the disc can be obtained by considering the configuration of the teeth:
- A straight tine cuts through solid wood quickly but messy.
- Alternately beveled cutters are suitable for all cutting directions, but are shock-resistant.
- The combination of flat and trapezoidal teeth prevents splitting of the top layer and is used for sawing slabs, plastics and non-ferrous metals.
- Combination cutters – a consistent combination of cutters with different sharpening, providing clear cut edges at good speed in materials of different hardness.
- The alternating concave and triangular teeth are ideal for cutting laminate without precut.
- The flat, chamfered teeth, combined with the wide backs, withstand the cutting line of cement or nails.
Estimate the disc body
Make an approximate conclusion about the quality of the disc by carefully looking at its canvas. For a normal saw, if you “play” it in the light, you can see grinding marks diverging in circles, indicating the calibration of a circle cut from a sheet. Low budget rigs do not have such stripes – a whole sheet was processed (or not polished at all) and balancing leaves much to be desired. And, of course, the surface should be smooth – no one needs resin sticking to roughness.
The slots located radially on the canvas dampen vibration, reduce noise and save from overheating. On “expensive” circular saws, thin spiral slots are additionally applied with a laser, and the body is covered with a protective layer. The cleanliness of processing and the working resource of the disc depend on the runout tolerance; for high cutting accuracy, this figure is 0.15 mm. There are copies that are more accurate, but for a household circular saw, their use is impractical.
Advice. A cheap disc wears out quickly and cuts worse, an expensive one cuts more accurately and lasts longer. Find your bar for price / quality: there is little point in purchasing “chic” equipment for 5 thousand rubles for a circular saw of the same cost.
The actual kerf depends on the size of the carbide insert, which affects the amount of chip removal. The thickness of the blade determines the clearance between the material and the blade, which is required for the saw blade to move freely. A reliable drive is thick and heavy, but requires powerful hardware. Thin circle gives less load on the engine and is optimal for battery models, but “gentle” and not suitable for intensive use.
Choose a drive for specific tasks
For neat cross-cuts in solid wood, decorative plywood and other panel materials, use a 50–60-tooth blade, which makes the bead look almost planed. Do most of the operations when high quality is not required with the cheaper 40-cutter wheel. Use a disc with 18–25 teeth for sawing solid wood along the grain, and in a circle with 10 teeth, unfold boards, constructing the frame of the sheathing, or carry out dismantling work in which chips do not matter.
Cut non-ferrous metals and plastics with discs with 60 or more incisors: with a negative inclination of the tooth for a thin-walled profile and positive for a thick-walled one. For cutting gypsum-fiber and cement-containing materials, take special wheels with 4-6 teeth, reinforced with artificial diamonds.
Do you want to get the perfect cut of the furniture board immediately for finishing sanding? If your circular is at least semi-professional, put a 40-cut disc with straight / trapezoid teeth and a negative slope (designed for aluminum and chipboard). Drive the saw slowly against sensitive resistance, possibly at full power. The result will be worth the inconvenience: the cut will come out smooth – for “zero”, and you will save the time that was previously spent on finishing the front edges.
There is no saw blade that fits every tool that can deliver quality and productivity at the same time. We have to select several options, taking into account the most frequently performed tasks.