Ushm Metabo 125 Variable Speed

angle grinder with speed control: features of the mechanism and scope of use. Important parameters for angle grinders with soft start: circle diameter, drive power, protection against jamming. A brief overview of the models Bosch, Interskol, Fiolent, Sparky and Metabo.

Metabo 125 adjustable speed

angle grinder with speed control are classified as professional tools. Devices of this class are usually produced with a soft start function. Such angle grinders are ideal for treating surfaces requiring delicate handling, such as wood or plastic. The ability to adjust the speed helps to carry out grinding work with the highest level of comfort and safety.

There is an opinion among masters that additional electronics in the case reduces the overall level of reliability of an angle grinder and increases the complexity of repair work. For this reason, some manufacturers have launched the release of individual electronic controllers that connect to the power cord.

Why do you need a soft start and speed control on angle grinder

On drills and screwdrivers with similar capabilities, the rotation control mechanism has a trigger structure. The operation features of the grinders do not allow the use of such devices, since the shape of the tool implies a complete girth with the palm of your hand. In addition, safety precautions prohibit changing the set rotational speed of a disk of a working angle grinder.

The scheme of smooth start-up and adjustment of rotation of the drive can be implemented only in devices using collector-type electric motors.

The angle grinder with the function of speed adjustment and gradual start-up is characterized by high reliability due to the reduced load on the electrical elements and the mechanical part of the tool.

In conventional angle grinders, at the time of starting, an excess voltage is applied to the rotor and stator, which sharply increases the starting current on the coils. This has a negative effect on the conductive elements. Despite the fact that manufacturers are designed to work in this mode, voltage drops in the home network sooner or later lead to inter-turn circuit.

A sharp transition from a standstill to an increased speed greatly wears out the gearbox, forcing it to work in overload mode. Everyone who has ever used an angle grinder knows the feeling when she breaks out of her hands when turned on.

The use of angle grinders with a smooth start allows you to avoid voltage drops in the network. This means that the included household appliances will not be at risk of burnout.

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Consider the practical benefits of the speed control function:

  1. There is a possibility of high-quality cutting thin-sheet products from tin or soft materials. Work at high speeds will lead to the melting of the edges of the product from exposure to temperature.
  2. Some ceramic products are cut at low speeds. Otherwise, small particles may break off on the spot, which spoils the appearance of the workpiece and can lead to injury.
  3. Grinding of various materials is carried out at various speeds. The adjusting mechanism will help you choose the optimal mode of operation without the risk of surface damage. This is especially important when polishing products with a low melting point.
  4. The spindle speed depends on the consumables used. For example, diamond blades operate at reduced speeds to avoid overheating of the contact surface.

Soft Start Angle Grinding Tips

Before purchasing an angle grinder, you must accurately determine its purpose. The most popular devices are powered by a network. They are distinguished by high performance combined with compact dimensions.

To work away from sources of energy, you should choose a tool that runs on battery power. This increases the cost and limits the operating time, but allows the use of angle grinders even in the field.

There are also gasoline and pneumatic angle grinders, which are used mainly in industrial enterprises. Devices with internal combustion engines do an excellent job of cutting dimensional workpieces with a diameter of up to 400 mm. Models powered by compressed air require a compressor with a capacity of 200-400 l / min.

Video: Ushm Metabo 125 Variable Speed

Consider other parameters that affect the choice of angle grinder.

Size of the used disks

All disks for grinders, including devices with a function of speed adjustment, are divided into two types: detachable and clean. The diameter of the circles varies from 100 to 500 mm. The most common sizes are:

On dimensional models, it is allowed to install discs of smaller diameter, provided that the mounting hole matches.

Experts do not recommend the use of circles, the size of which exceeds the passport indicators. This will make the angle grinder work in overload mode, which reduces its resource.

Remember: the larger the disk, the more massive the device will be. This will affect the duration of the work cycle.

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Engine power

Among newcomers there is an opinion that the more powerful the drive, the more resourceful the tool will be. This is mistake. The angle grinder speed is a standard value, which depends on the diameter of the circles. Nozzles also have a limit on the number of revolutions.

The power of household models does not exceed 1 kW. For professional devices, this parameter can reach 5 kW.

Depth of cutting directly depends on the value of this parameter.

Availability of manual and electronic protection

Biting a disc during operation is the biggest nuisance. The angle grinder can escape from your hands and cause serious damage. Possible reasons:

  • contact of a circle with a foreign object;
  • work with too strong subject;
  • weak tightening of the spindle nut;
  • exceeding the maximum speed of the nozzle;
  • operation of a disc whose material does not match the surface to be treated.

All this leads to the fact that the working nozzle breaks or shatters into parts. In the latter case, fragments flying at high speed pose a danger to human health.

To reduce the risk of injury, manufacturers equip the tool with anti-jamming mechanisms.

All low-cost models have a special casing to protect against disc fragments in case of jamming. These are international safety requirements.

Security systems can be divided into two types:

  1. Mechanical. On professional models with a function of speed control, special couplings are installed. In case of overload or jamming of the disk during the transmission of torque, it begins to slip, preventing damage to the nozzle.
  2. Electronic. In this case, a special safety unit is responsible for the emergency stop. Its principle of operation is based on reading electrical parameters during operation. A sharp cessation of rotation is accompanied by a surge in current, to which the sensors instantly react, de-energizing the tool.

Other functions

In addition to adjusting revs and other useful qualities, modern models are equipped with the following functions designed to increase work safety:

  1. Protection against accidental inclusion. Two trigger buttons are installed on the angle grinder. Switching on occurs only when pressed simultaneously.
  2. Load stabilizer. When cutting particularly dense materials, the electronic system automatically maintains a predetermined number of revolutions. The function is useful to craftsmen who work with dimensional workpieces made of stone, marble or concrete.

Overview of popular models of grinders

We bring to your attention a brief overview of the most popular angle grinder models with speed control from leading manufacturers:

  1. Bosch GWS 850 CE. Excellent angle grinder from a reliable German manufacturer. The function of speed control allows you to choose the optimal mode of operation. Speed ​​varies from 2800 to 11000 rpm. Ideal for working with natural granite, marble and other durable materials. The average price is 80.
  2. Metabo WEF 15-150 QUICK. A high-quality tool with the ability to adjust revolutions under a circle of 150 m. A special feature is a low-profile gearbox that allows you to perform work in hard-to-reach places. There is a built-in protection against jamming of the disc and a system of stabilization of work under load. A dustproof engine is installed. The only drawback is the high price compared to peers. She is 260.
  3. "Sparky" M 750 E. The Bulgarian professional tool under a disk of 125 mm. The maximum rotation speed is 10,000 rpm. The spindle design provides reliable protection against dirt and dust, and the locking button allows you to replace the nozzle in the shortest possible time. There is protection against arbitrary start. Users highlight one minus. large dimensions, which does not always allow you to reliably hold the angle grinder with your hand. The average price is 55.
  4. "Fiolent" MSHU-2-9-125E. angle grinder from a well-known Russian company with a capacity of 900 watts. It has all the necessary additional functions, including speed control and soft start. A well-designed ventilation system prevents dust accumulation and provides effective cooling. Among the shortcomings, there is a backlash of the protective casing and rather expensive parts for repair. The average price is 60.
  5. Interskol UShM 125-1100E. Reliable tool with high-strength plastic housing. The handle has a rotatable design with the ability to adjust in three positions. The speed range is 3000–10000 rpm. The gear housing is made of magnesium alloy. The main disadvantage is the high cost of spare parts. The average price is 70.
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an angle grinder with speed control is a universal tool that can work with almost any material, regardless of its thickness. And what do you think, is there a need for a built-in function or is it better to purchase a separate device? Some masters prefer to make a speed control system on their own. What do you think about this? Write your opinion in the comments section.