How To Properly Install The Cutting Disc On The Grinder

Selection and replacement of discs for grinders
What are the types of grinder discs, their typical sizes. How to correctly change the nozzle on the grinder. What to do if the disc is stuck and the nut won’t loosen?

Selection and replacement of discs for grinders

An angle grinder (angle grinder), commonly called a “grinder”, is widely used at construction sites and in everyday life during repairs. It can be used to carry out many different technological processes. In order to choose the right tool for performing a certain type of work, you need to familiarize yourself with what kind of discs and nozzles for angle grinders are. The tool for this device is selected by its size and function.

Using a puncher

Some owners of grinders, in a situation where the clamping nut is jammed, install a “chisel” or “jackhammer” nozzle into the hammer drill, insert it into the hole of the flange at an angle and turn on the jackhammer mode without rotation. Accordingly, the stop button must be pressed. Just a couple of gentle clicks with a perforator are enough (so as not to break the shaft retainer), and the nut will begin to turn.

Purpose of discs and attachments

Grinder wheels differ in purpose for:

  • Detachable;
  • Stripping
  • Grinding;
  • Sharpening.

Cutting discs

The most common task performed with a grinder is cutting various materials. The choice of tool material also depends on what material needs to be cut.

  1. Metal cutting. The metal cutting disc is made from crystalline alumina corundum, as well as from a synthetic corundum called fused alumina. The main color of wheels for cutting metals is blue.
    How To Properly Install The Cutting Disc On The Grinder
  2. Cutting stone and concrete. For cutting stone, you should choose a disc made of another abrasive material. Silicon carbide. This abrasive cuts white brick (silicate) and slate with ease. But to cut red brick, some types of concrete or ceramic tiles, this circle material will not work. Stone discs are available in green.
  3. Cutting ceramic tiles, red brick, porcelain stoneware and concrete. For these purposes, a diamond disc is already used. This nozzle is made of metal, an abrasive mass with diamond chips is applied to the cutting edge. The picture above shows a segmented saw blade designed for dry cutting of material. All-metal discs require water cooling during operation.
  • Wood cutting. Although there are saw blades for wood on the market that are no different from circular saw blades, it is best to avoid using them for safety reasons. When working with such a tool, the user often receives serious injuries due to jamming, bouncing, accidental slipping of the tool, etc.
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    Therefore, if you are still going to use a saw blade for wood, then you should adhere to safety measures. A protective cover and a handle must be installed on the grinder, the user must wear a protective mask or goggles. In addition, you must not use this tool to cut materials that are not intended for it.

    Using a penetrating lubricant

    Liberally spray the flange-shaft connection with WD-40 fluid. It tends to penetrate into inter-threaded spaces and small cracks. After applying the liquid, wait about 5 minutes and try to unscrew the fasteners with a standard wrench.

    Typical disc sizes

    When choosing a disc for a grinder, you must make sure that the outer diameter of the nozzle does not exceed the maximum allowable values ​​allowed for your angle grinder. For example, if a grinder is designed to use a circle with a maximum diameter of 125 mm, then a 230 mm circle cannot be installed on it. And there are several explanations for this:

    • The linear speed of the cutting edge will be exceeded, which is fraught with destruction of the abrasive wheel and injury to the user;
    • A small grinder does not have enough power to work with a large tool;
    • Installing a nozzle that exceeds the permissible dimensions requires removing the protective cover, and this is already a violation of safety rules.

    Discs for angle grinders have standard sizes: 115, 125, 150, 180 and 230 mm. In modern grinders, the landing diameter (the diameter of the shaft on which the tool is installed) is practically the same and is equal to 22.2 mm. If you have an outdated grinder “lying around”, then you will need to use adapters. Rings of different diameters.

    All abrasive wheels of any size have a special marking, from which you can find out the following information: the diameter of the disc and its thickness, the diameter of the seat, the maximum rotational speed, as well as what materials it is intended for processing.

    How to put the disc on the grinder correctly?

    To put the disc on the grinder correctly, it should first be noted that the disc is installed on the grinder spindle using a special clamping flange with M14 thread. Let’s take a closer look at how to remove a disc from a grinder. In order to unscrew the disc from the grinder, you first need to dismantle the flange. Especially for such purposes, manufacturers complete the grinders with a special open-end wrench. It has a specific shape. The pins located on the arms of this key are inserted into specially provided holes on the flange.

    To unscrew the flange, we fix the spindle. To do this, we clamp the latch, which is usually a button on the top of the case. When pressed, the cotter pin is placed in the hole of the driven disc of the gearbox, and this in turn prevents it from rotating. Next, we insert the pins of the key into the specially provided holes on the flange, pressing the retainer, you must simultaneously turn it counterclockwise and move the flange from its place. If the manipulations were successful and the flange gave in, you can unscrew it by hand and put it aside.

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    Now let’s dismantle the disk. Often, in the process of intensive work with the tool, a kind of plaque from small particles of metal and abrasive material forms on the inside of the protective casing. For optimal, stable and durable operation of the grinder, remove the lower part of the flange and clean the casing with a steel brush.

    Method number 1 to remove the disc from the grinder

    First, figure out which way to unscrew the nut.

    The flange must always be turned in the direction in which the disc rotates.

    For this kind of work, you will need either two gas keys or two clamps.

    Here’s what you need to do: destroy the remains of the disc, fix the washer located behind the disc with one key, unscrew the flange with the second.

    Method number 3 to remove the disc from the grinder

    This method is used in extreme cases.

    What should be used to install the disc?

    In fact, the process of installing a disc into a grinder is not so difficult. However, in order to do such work, it is necessary to take into account certain rules and use certain tools.

    In particular, installation may require:

    1. The key with which the nut is loosened.
    2. Next, you need the disk itself.
    3. A hole or chisel may be needed. These tools must be used in the case when the disc is clamped and it will have to be removed by opening, which means that the residues in the gap can be eliminated with a chisel. You may not need these tools, but it is best to have them on hand.

    Which side is suitable for installation

    In order to determine which side to install the disc, several main factors must be taken into account.

    In particular:

    In order to determine in which direction the grinder should turn, here you need to refer to the safety information. In particular, the concrete must be cut on itself.

    In this case, the sparks will fly from the side, namely from the manager. In general, it is not safe to cut materials in the direction away from you, since in case of jamming, the grinder with the disc will fly towards the one who controls it. This must be taken into account.

    Grinder discs differ among themselves in the following main features:

    1. Outside diameter;
    2. Disc thickness;
    3. The material from which the disc itself is made;
    4. The characteristic of the maximum rotation speed;
    5. And, of course, the area of ​​the proposed work.

    For a better understanding, let’s look at the main types of grinder discs and give a definition of their application:

    1. Cut-off wheels. These are the most widely used grinder consumables. Their main purpose is to work with metal, stone and wood. A variety of cutting wheels for the grinder are diamond discs. This is a heavy-duty tooling for processing high-strength materials such as reinforced concrete, tiles, porcelain stoneware, marble.
    2. Grinding and roughing wheels. As the name implies, this type of disc is used for grinding various materials, for example, polishing products made of stone, or for removing (roughing) the top layer, for example, removing a layer of rust or old paint coating.
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    Why do you need a metal ring

    The metal washer (ring) is designed to protect the integrity of the disk when it is tightened with a movable flange nut, as well as to increase the bearing surface area. In addition, the metal washer does not allow the cutting wheel to stick to the nut surface, which greatly facilitates the process of replacing it.

    Guaranteed even installation on the shaft

    The metal ring increases the footprint. Therefore, when the disc is mounted on the shaft and starts to tighten with the nut, the pressure is evenly distributed. This ensures a smooth fit of the cut-off wheel and reduces the possibility of damage due to skewing.

    The advantages of installing a disc with a ring to a grinder

    The cut-off wheels do not have a programmed direction of rotation. Therefore, it does not matter which side will carry out their installation. But as mentioned above, installing the circle with its front side outward makes it easier to replace it (it is much more difficult to unscrew the nut on the abrasive side). In addition, this arrangement provides several other advantages.

    Prescribing instructions

    The instructions for many angle grinders, such as the Metabo WP 850, clearly state that “the metal flange of the abrasive cut-off wheels must be in contact with the support flange”. It is not in vain that manufacturers give such recommendations, since they ensure safe operation of the tool, and reduce the risk of serious injury to the master.

    The main difference between the two sides of a circle

    On any cutting disc, two surfaces are clearly visible. One of them (back) is plain, formed by abrasive material. The second (front) has a label containing basic information about the characteristics of the disc. But the main distinguishing feature of the two surfaces is the presence of a metal ring on the front side.

    Which side to put the cutting wheel on the grinder

    Angle grinder (angle grinder) or, as it is also called, “grinder” is a widespread tool with which craftsmen saw, cut, grind various surfaces. During work, it is often necessary to replace the working disk. And at this moment, many people have a question about which side to put the cutting disc on the grinder.