Grinder with speed control: models, characteristics, subtleties of choice

Every master has at hand such a reliable tool as an angle grinder. With the help of this device, you can not only perform high-quality cutting of material, sand the surface, but also sharpen kitchen knives. Since certain types of work require minimal disc rotation, it is recommended to purchase a device with a speed control.

The variable speed angle grinder is a versatile and multifunctional tool that makes it easy to handle any task in construction and renovation. The main difference between such angle grinders is the ability to independently set the speed of rotation of the disk, depending on the type of material being processed. Manufacturers produce a device with an electric motor, the power of which can range from 500 to 1500 watts. For cutting workpieces, you can choose machines with an average performance of 800 W, but if you plan to carry out grinding, then it is recommended to give preference to more powerful models, since the contact area with the surface of the material being processed is larger in this case.

LBM with speed control is an absolutely safe device to use, since all models are equipped with a full range of protective systems that exclude injury. Let's list the main ones.

• Soft start device. It is responsible for the smooth operation of the tool after pressing the start button. This device can also act as an inrush current limiter, which extends the life of the device.
• Safety clutch. In the event that the disc of an angle grinder starts to "bite" or wedge during material processing, this device triggers an emergency stop.
• Emergency brake. When machining hard material, the tool can twist and pull out of the hand. The brake helps to stop the disc rotation in 3 seconds.

• Coil impregnation with a special compound. Since the cutting and grinding of the material is accompanied by the appearance of abrasive dust, its penetration into the device is prevented by additional processing of the coil with a protective layer. This avoids short circuit problems.
• Heat dissipating slots. Protect the device from overheating during intensive work.
• Balancing system. The wheels of the machine may be ground unevenly, after which trembling and beating of the machine may occur during the processing of workpieces. Special automatic balancing helps to smooth the work.
• Overload fuse. When the cutting part heats up to a temperature above 160 degrees, the automatic system is triggered, and the rotation speed of the disc first decreases to 200 rpm, then stops completely.

LBM with a speed controller weigh from 2 to 5 kg, their performance depends on the diameter of the disc and the number of revolutions. Mini-models are very popular among craftsmen, which are suitable for working with 115 and 125 mm wheels. Their speed ranges from 10,000 to 11,000 rpm. Angle grinders with 115 mm discs are generally used for cutting material no more than 28 mm thick and are well suited for sanding wood, tiles, porcelain and glass.Devices with 125 mm discs are considered the most popular, as they perfectly cope with grinding the surface of any material and cutting parts with a thickness of 30 mm. If it is necessary to cut and grind steel pipes, bricks and concrete, then it is recommended to use a device with a circle of 150 mm, while metal processing should be carried out at high speeds, and stone at lower speeds.

The fastening of the cutting disc in a grinder with speed control is carried out using a spindle stopper and a protective key, in some models there is also a self-clamping system. In addition, manufacturers also equip the tool with a casing that protects the craftsman from dust, sparks in the eyes and breaking the circle on the go.

The quality of cutting and grinding of the material directly depends on the set speed of rotation in the angle grinder. Since hard and thick workpieces lend themselves well to cutting at maximum speed, and aluminum, on the contrary, can melt when heated, then when working with them, the speed of rotation of the disk should be adjusted. Control of operating modes is provided only in models equipped with a special controller. This function is useful and used in several cases.

• When processing stone. This material is well cut and polished at low speeds; for each type of stone, its own disc speed is selected separately.
• For finishing delicate surfaces that require careful handling. At high speeds, such products can deteriorate.
• When replacing one circle size with another. In this case, a speed correction is needed.
• When using in the work of crowns and discs with diamond dusting. To avoid overheating and breakage, workpieces must be processed at low speeds.

If the tool is only planned to carry out threaded operations, then there is no need for a speed controller. With the universal use of the grinder, it is irreplaceable. The speed control system in angle grinders is represented by integrated microcircuits. They are reliable in use, function with a soft start system and a tuned module.

Angle grinders with speed control are presented on the construction market in a huge range. Depending on the design features and technical characteristics, they can have both pros and cons. So, household models are compact and lightweight, but their functionality is limited. In such devices, productivity is also reduced, during operation they quickly overheat and require constant stops.

As for professional tools, they are very powerful and endowed with additional functions that allow them to be used for a long time without overheating the mechanism. Such grinders have excellent quality, are easy to use and are designed for both cutting and grinding workpieces. The disadvantages of these models are the high price and high weight, since the frame of the device and additional components are made of durable material.

Today, angle grinders equipped with speed control are in great demand among craftsmen. This type of tool is well suited for cutting, polishing and grinding workpieces. The construction market is represented by angle grinders produced by both domestic and foreign companies. Models of several brands have proven themselves well.

• Bosch GWS 850 CE. This device is lightweight for easy handling.The machine has a power of 850W and is good for polishing marble and granite. The set of the tool includes a disc speed regulator with six positions. The minimum speed of revolutions is 2800, the maximum is 11000 per minute, a special nozzle designed for high speed is used for processing wood with a machine. The manufacturer additionally equips the device with a handle, a wrench, discs and washers for attaching nozzles.

• Makita GA5030. It is the lightest grinder (weighs 2 kg) and is designed for simple household work. With the device, you can easily cope with cutting, grinding and polishing various materials. Thanks to the additional handle, the workflow is greatly simplified, this model can accommodate discs with a diameter of 115 and 125 mm. The tool has a power of 1400 W, thanks to the speed control it is classified as a professional model. In addition, the angle grinder has a turn-on lock, a speed stabilization system, in order to protect the device from overheating, it is recommended to turn it off periodically during intensive work.

• Metabo WEV 10-125 Quick. This modification is produced with the ability to change the speed and maintain a power of 1200 W, the design provides for an electronic engine overload protection system. The speed of rotation of the cutting wheel automatically changes depending on the type of work and is fixed at varying loads. Of all the 125 mm cars produced, this model is the best, it has a large number of revolutions and adjustable speeds. The angle grinder also has a safety clutch and replaceable brushes that turn off when there is a voltage drop in the mains. In addition, the manufacturer has supplemented the tool with an overheating indicator, a stabilizer and a long cable.

The Hitachi G13SS modification can complete the review of popular angle grinders with speed control. Due to its high power indicators and the possibility of using it with discs with a diameter of 150 and 230 mm, it occupies a high rating among the types of this equipment. The device is perfect for both renovation and construction work. The device can cut metal workpieces and grind parts from different materials. A distinctive feature of the device is its narrow grip and low weight, which makes it comfortable to work with.

The variable speed angle grinder is one of the most popular and widely used tools. Since this tool is represented by different modifications, it is difficult to make the right choice in favor of this or that device. The first step is to decide how the device will be used for domestic or professional purposes. In the event that infrequent and simple work is planned, then a small low-speed machine will do. For the simultaneous implementation of high-quality cutting and grinding of the material, it is best to opt for professional models.

In addition, it is worth paying attention to the following characteristics of the device:

• performance:
• minimum and maximum number of revolutions;
• additional functions;
• disk parameters that can be used with the instrument.

An important criterion when choosing is the frequency of operation of the device. For constant and intensive work, it is necessary to buy models in which the outer case is made of durable metal and supplemented with brass inserts. When installing the pipeline, it is advisable to use devices with the maximum level of protection against water and dirt.

Despite the fact that all models of angle grinders with speed control serve flawlessly, they still require proper care and operation. Therefore, it is periodically necessary to replace the working attachments and contact brushes, add oil to the gearbox and clean the engine compartment from dirt.In addition, a technical check of the tool is also provided; it should be carried out at least once a month.

When replacing the disks, the device must be turned off, the gearbox must be locked with the button, then the old nozzle must be removed and a new one must be installed, pressing it tightly with a nut. Filling with oil is simple: to do this, remove the gearbox cover by first unscrewing the mounting bolts. As for cleaning the case from dust, it is carried out using a vacuum cleaner.

Working with angle grinders must be carried out in accordance with all safety regulations. The technician must wear protective gloves, goggles or a face shield. Do not start cutting with a broken or cracked blade as it could cause injury. Grinding with a cut-off wheel is also not allowed, and cutting with a stripping disc.

Slicing and polishing different materials requires a certain speed of rotation of the disc, it can be adjusted using a special automatic system, which is controlled on the body by moving the lever. Thus, the revs can be easily decreased or increased. In addition, you can reduce the speed using large diameter discs.

For information on how to properly adjust the speed of the grinder with your own hands, see the next video.