Circular saw: which to choose and how to use

Recommendation points

• What are circular saws used for
• Cut-off machines with abrasive disc
• Tungsten carbide saws
• Key features of chain saws
• What are the additional options

When assembling structures made of metal or wood, it is often necessary to cut the part accurately, evenly, without scoring and sagging, or even at a certain angle. In this article, we will talk about the types of circular saws and their application, both in material processing and in repair work..

Very often, circular saws and machine tools are classified as highly specialized equipment, or even call these devices stationary and consider them to be installed exclusively at permanent workplaces in workshops. This is not at all the case: there are different classes of such a tool, both mobile and intended for processing heavy and massive parts..

What are circular saws used for

In a number of assembly and assembly operations, the exact dimensions of the parts are critical. The simplest example is assembling a door frame from a square shaped tube. External corners of this design are formed by undercutting at 45 °, and a deviation of 1-2 mm can negatively affect the quality of the weld or the geometry..

With the help of angle grinders, only a few professionals with a steady hand can achieve such a cutting accuracy. Therefore, for accurate trimming of metal, cutting saws, machines or machine tools, also called assembly or lever saws, are used..

In addition to metal, such equipment perfectly copes with cutting plastic profiles, wood and many other materials. There are no problems with cutting thin metal products, such as a galvanized profile for gypsum board.

Editing saws are indispensable when cutting a large number of parts to exact dimensions is required, while the quality of the cut, the absence of scoring and burrs from the weld metal are also important. Even in a home workshop, a simple saw for 5-7 thousand rubles will find an honorable place and application, not to mention large construction projects, where workhorses from DeWalt or Metabo make several hundred cuts every day.

Cut-off machines with abrasive disc

In the most common cutting machines, abrasive saw blades with reinforcement are used, similar to cutting wheels for angle grinders. On average, one blade is enough to make 50–100 cuts. Please note that as the blade is triggered, the diameter decreases, respectively, the maximum cutting depth decreases. This drawback is not so important if work is underway on parts of different formats, however, when processing only massive workpieces, the disk will stop cutting them in one pass and the part will have to be turned over, sacrificing accuracy and quality of the cut.

The second disadvantage of abrasive discs is their low rigidity and strength. When sawing parts with a beveled surface, the abrasive wheel will inevitably move by 1–1.5 mm, with normal cuts, accuracy also inevitably suffers. However, if filigree trimming is not required, abrasive discs are ideal for mass processing of steel parts, including those made of hardened alloys. Unfortunately, cutting aluminum and other soft metals is much more difficult, and wood and plastic on such machines will not work at all.

Tungsten carbide saws

Some models of edging saws have a circular blade with victorious teeth. Contrary to negative criticism, these blades do an excellent job of cutting rolled metal, and the process is much faster, and the cut quality is almost perfect..

The key difference between saws for such discs is the low spindle speed. Tungsten carbide teeth “gnaw out” metal particles rather than rubbing them off as abrasive wheels do. There are practically no sparks during cutting, the saw is much quieter and can cut parts of any profile and complexity, including plastic or wood.

Actually, this is the main feature of saws with carbide discs: high accuracy, complete absence of errors and constant maximum cutting depth. Many are deceived by the fact that the resource of a carbide disc is 20-30 times higher than that of abrasive discs (about 1-1.5 thousand cuts). However, discs with victorious teeth are about 100 times more expensive than abrasive ones, so it is unreasonable to use them for frequent cuts and rough processing..

Key features of chain saws

The specifics of using a particular model of a circular saw is quite simple to determine by its weight. The pruning saws have a curb weight of up to 15 kg and can be easily moved both around the object and between them. Circular sawing machines are in the range from 15 to 30 kg. They are used at large facilities and temporarily equipped workplaces. Saws weighing more than 50 kg are used exclusively stationary and are called cutting machines. Please note that the greater the mass of the tool, the more stable its bed and the higher the cutting accuracy..

The second key difference lies in the kinematic scheme: saws come with direct drive and belt transmission. Direct drive is used in almost all household and semi-professional models. The belt drive serves as a kind of protection when, when processing large parts, the load on the disc increases greatly. If it gets stuck, the belt will simply turn on the pulleys, eliminating the motor stopping and overloading. In addition, often the belt drive has stepped pulleys, which allows different types of discs to be used on the same machine..

Additionally, all saws are classified by the diameter of the blade mounting hole. The most common discs are inch discs with a 25.4 mm hole. When buying a saw with a less common fastening nut diameter, for example, 30 mm, you may experience difficulties in providing the tool with consumables..

What are the additional options

The design of each individual model is unique: manufacturers seek to improve their instrument with various modifications. The most useful ones relate to three structural units.

First of all, the convenience and quality of cutting is determined by the design of the positioning table. The guide rail has a swivel mechanism and graduation with an accuracy of 1, 5 or 15 degrees. If corner trimming is performed frequently, models with a quick fixation of the guide rail with a handwheel requiring no tools will be very useful. When cutting, the workpiece is pushed in with a screw-fed rotary jaw, which may have a swing-out lever for faster adjustment to the size of the workpiece. This assembly has always been considered the weak point of circular saws, therefore, when single-format cutting, it is better to give preference to the classic flywheel screw without additional options..

The second useful feature is the electronic engine management system. It includes a soft start function, which reduces the load on the power grid, and is additionally equipped with an electronic stabilizer that maintains the rated speed regardless of the applied load..

The third important knot is the swing arm. It should be based on angular contact bearings and have a self-return spring mechanism. In practice, it is very useful to have a handle for locking the saw in the transport position, cheaper and simpler models use a conventional chain for this.