Diamond wheel for sharpening: how to choose a turning tool

Asphalt, concrete and stone are all materials that have a high degree of hardness. Therefore, specialized equipment is required to process them. The most effective way to cope with this task is a diamond cutting wheel, which looks even more preferable compared to an abrasive one. After all, it not only maintains the initially specified cutting depth, but also has the optimal diameter and rotation speed for quickly and accurately cutting these materials. It is thanks to these advantages that diamond discs are widely used in industries where large volumes of products have to be processed.

Manufacturing of diamond wheels

To obtain a consumable material with the necessary characteristics, it is necessary to strictly follow the manufacturing technology of this tool. In accordance with it, particles of artificial materials are used as the main raw material for this tool, which are placed in special molds along with a binder for subsequent pressing on special equipment.

Diamond wheels of different brands can be used for cutting high-density materials. To select the most suitable consumables, it is necessary to consider the size of the diamond particles used to make them, as well as the type of binder, quality and level of artificial diamonds.

In the process of producing diamond blades for processing hard materials, the finished segments are mounted on a metal body. This can be done in several ways:

• laser welding;
• silver soldering.

The first method has become widespread in the manufacture of tools for dry cutting, and the second - for wet cutting. Since the melting point of silver is approximately 700 degrees, this method of mounting finished segments is used primarily in the manufacture of high-quality sharpening wheels. At this stage, a diamond blade of fairly good quality is obtained, which is not yet ready for use due to its lack of cutting capabilities.

A diamond wheel for sharpening turning tools is considered ready to perform its main task, that is, sharpening, only when its segments are ground off. This operation is performed using a ceramic sharpener, and the wheel is ready for use only when diamond fragments begin to be visible during the sharpening process. Based on this feature, it is determined that the cutting wheel has acquired cutting properties.

When choosing this sharpening material in a store, you must carefully consider its surface - the circle must have a special arrow applied by the manufacturer, which helps determine the correct direction of rotation. You will need this information when it comes time to install the blade on the cutting machine shaft.

Scope of consumption of diamond wheels and classification

Diamond sharpening wheels are intended for sharpening saws made of hard alloys, they are used to refine soldering, they are indispensable for sharpening turning tools, etc. They have a fine structure that allows finishing of the workpiece, which cannot be done using an ordinary standard one. abrasive sandpaper. Grinding discs of different types, types of diamond and grain size on mechanical and organic bonds are used for refining and sharpening turning tools, milling cutters and other devices made from hard raw materials. The Russian market for diamond wheels is represented by products of various shapes:

• plate;
• cup;
• profile;

Which disk to use in each specific case must be determined individually, based on the proposed workpiece, surface, area and manufacturability. If a circular saw requires a circle plate, which, thanks to its sharp edge, can work between the teeth, then a straight profile or cup would be more suitable for a knife. To restore the original quality of turning cutters, drills and other devices, it is necessary to use reliable sharpeners.

Diamond blade shapes

Grinding wheels are also distinguished by grain size:

• 100/80 – fine fraction;
• 125/100 – average;
• 160/125 - large;
• 200/160 – larger;

Products with fine grain are used for final finishing of turning tools, knives, blades, etc. Using products with a medium grain, you can achieve the required sharpness of the cutting part of the device. The coarse grain structure allows, for example, to remove part of the metal and align the cutting part of the part. Products with fine and medium grains are the most common; they are also used in everyday life.

The sharpening disc is distinguished by diameter (125–300 mm). Therefore, you need to select it based on the size of the existing sharpener. The thickness and width of the diamond layer is considered important in such products. A wide layer will allow you to conveniently process a part of a decent area or a large diameter with a drill; in addition, the wear of the diamond coating will be prolonged.

Diamond sharpening wheels are universal; they can restore the cutting capabilities of a product that has failed, and after completing this procedure, return it to the technological process. It is used for sharpening end and disk mills, cutters, drills of different diameters; such a tool, after processing, is distinguished by decent cutting abilities and accuracy.

A distinctive feature of such a grinding wheel is the presence of a fine fraction of diamond grain on the working part; it has been proven in practice that it is capable of performing precise finishing of the cutting part of a cutter, plate, knife and other tools. Depending on the purpose of use, the choice of diamond wheel for sharpening is made. For finishing, they use a straight profile sharpener.

Right choice

In order to choose the right consumables for sharpening, it is necessary to take into account a number of the following parameters when studying various products:

• Type of cutting machine and material being processed. If you plan to make deep cuts, then the selected disk must be of the appropriate size. Effective operation of the tool is only possible if the working disk is suitable in size for the cutting equipment.
• Shape of cutting wheel teeth. This parameter depends on the type of material being processed. It is important to take it into account when choosing a diamond blade, because the speed and cleanliness of the processing depends on it. However, sometimes you come across materials with a soft structure that can be easily cut with diamond discs without teeth. Thanks to the use of such material, damage can be avoided.

There are also other parameters that need to be taken into account when choosing a diamond grinding wheel for sharpening:

• Capabilities and technical parameters of the cutting wheel.
• After purchasing sharpening material that meets the necessary requirements, you need to properly attach it to the shaft of the cutting machine.
• It is necessary to ensure that after switching on the machine shaft and the disk have the same direction of rotation. You can understand how to correctly install a diamond wheel for sharpening a tool by looking at the arrow located on the body, which many manufacturers apply to their products.

Other selection criteria

Sometimes you come across sharpening stones in the store that may not have an arrow on the body. If you are interested in just such a diamond blade, but you do not know whether it is worth purchasing, we recommend that you refer to the documentation. Keep in mind that the rotation speed of the diamond grinding wheel should be the same as that of the cutting machine. This is a very important point, given that sharpening materials from different manufacturers often have different rotation speeds. To find out, we recommend that you refer to the documentation that came with the cutting tool.

We pay special attention to the fact that the installation, as well as the operation of the diamond wheel for cutters, must be carried out in strict compliance with the manufacturer’s instructions. Otherwise, it will not only negatively affect the processing efficiency, but also may damage the incisors. Therefore, we advise you not to rush into choosing a diamond blade. First you should find out the technical characteristics of the machine on which you are going to use it.

Rules for using diamond wheels for metal

In order for diamond wheels for metal to last as long as possible, you need to follow the recommendations of specialists and the rules for using tools.

How to properly install diamond wheels on spindles

1. It is prohibited to install diamond wheels for metal on full-size, small-size or oval spindles. Here are the recommended differences between the diameters of the spindles and the diameters of the mounting holes in the tools.

Table No. 3: recommended differences between the diameters of the spindles and the diameters of the mounting holes of diamond wheels

1. If the difference is less than acceptable, then the hole should be bored. Otherwise, there are two options. Most often, bushings of suitable sizes are used. The hole in the circle can also be narrowed by pouring a special mass.
2. The circles are secured using clamping washers. Gaskets are placed between them and the tools. It is not recommended to clamp the circles too tightly. High pressure can cause the device to break.

Rules for using diamond wheels for metal

1. When processing workpieces with diamond wheels on ceramic or metal bonds, it is imperative to use coolant. When working with wheels with organic bonds, the use of coolant is recommended.

2. After installing the tool, you need to check it. To do this, the equipment is started idle at the operating speed. In this case, a protective casing must be installed. You can start working only after the disk has passed the strength test. The runout should also not exceed the established norm.

3. When processing, it is prohibited to use levers that increase the load on the tools.

4. Cooling fluid must be supplied and discharged evenly and in a timely manner. Constant immersion of the circle in the composition is not allowed.

5. Diamond wheels for metal are cleaned in different ways.

1. Pumice stones are used to remove dirt from instruments with organic bonds.
2. Circles on metal bonds are cleaned using silicon carbide bars. The grit of the device should be 1–2 numbers coarser than the grit of a diamond wheel for metal.

6. To restore the cutting ability of diamond tools, dressing is used. It involves treating the working surface with diamonds, diamond substitutes or cutters.

How to properly store abrasive tools

1. It is recommended to store diamond wheels for metal on racks.
2. The room should be bright and heated.
3. The storage temperature for ceramic bonded circles is not lower than +5 °C.
4. The storage temperature for bakelite bonded wheels is not lower than +10 °C.
5. It is recommended to place tools on racks in groups. For example, depending on the form.

Photo No. 3: an example of organizing the storage of abrasive tools

Editing methods

Diamond wheels are one of the most optimal ways to process products made from high-strength materials, as they provide high efficiency in this operation. But we must not forget that this is a consumable material that will wear out over time, and this will certainly negatively affect the cutting properties of diamond grains. There are several ways in which you can return these sharpening stones to their former cutting properties. Each of them has its own characteristics that must be taken into account before choosing the most suitable one.

Electrolytic method

If you notice that your blade’s cutting characteristics have deteriorated, we recommend that you start restoring them with electrolytic straightening. The essence of this method is that the gap created by the circle and the electrode is filled with electrolyte. Oxidation of the bond is a mandatory requirement for correct dressing of the sharpening wheel. This will make it possible to obtain an insulating layer that will reduce the electrical conductivity of the circle and allow you to influence the consumption of the number of grains.

Thanks to the insulating layer, you can polish the surface being treated. But this layer is also short-lived and will wear out over time. As soon as you notice this, you need to carry out the above-described editing cycle again.

Electrochemical straightening

This method of dressing a sharpening wheel is not much different from the electrolytic method. To do this, you do not have to create an insulating layer. The working surface of the disk is cleaned of oxides using an electrolyte. Thanks to this dressing method, conditions are created for the continuous removal of abrasive grains. It is noteworthy that the size of grains leaving the circle can be about 110% of the average diameter.

Restoring the cutting characteristics of a wheel using this method is carried out using a conventional grinding machine. The essence of the procedure is to place a copper electrode on the grinding wheel. The gap created by the circle and the electrode is subsequently used to supply electrolyte.

To select the appropriate type of diamond blade, you need to pay attention to such a characteristic as the size of its internal hole, which should not differ from the diameter of the cutting machine. It is possible to perform high-quality processing of hard materials using a diamond wheel only if there are no gaps between the internal hole and the disk shaft.

Design and common shapes of diamond wheels

Let's tell you more about the design of a diamond wheel. Its main part is a durable disk with a hole.

Image #1: Diamond wheel design

Discs are made from materials of two groups.

1. Structural steels (St20, St3, etc.). Discs made of these materials are characterized by increased resistance to mechanical loads and vibrations. Steels dissipate heat well.
2. Aluminum alloys (D16 and AK group alloys). They have excellent thermal conductivity, but less strength. When processing workpieces at high speeds, discs of these materials are prone to vibration.
3. Composite materials with the addition of polymers. Discs made from them are characterized by maximum vibration resistance, but strength and thermal conductivity leave much to be desired.

Some surfaces of the disk (1 more) are covered with a working layer. It includes:

1. filler (this is powder made from boron carbide, electrocorundum, alumina, copper or graphite);
2. ligament;
3. diamond powder.

It is the working layer that comes into contact with the workpiece during processing.

Features of ligaments

In the manufacture of diamond wheels for metal, three types of bonds are used.

1. Bundles on metal bases. The latter include composites of zinc, aluminum, copper and tin. Metal bundles:

1. are characterized by maximum strength;
2. have high heat resistance;
3. when used, the instruments do not become deformed for a long time;
4. serve for a long time;
5. quickly pickled;
6. increase the productivity of diamond wheels for metal.

Tools with such bonds are used to remove large amounts of metal from workpieces. The main operation is pre-processing. The resulting surface acquires an eighth-ninth class of roughness.

2. Organic ligaments. They have low strength and heat resistance. Productivity and processing speed are at a high level. The tools are little greasy, but the working surfaces wear out quickly due to the increased consumption of diamonds.

Diamond wheels for metal with organic bonds are used when processing workpieces made from the following materials.

1. Hard alloys.
2. Difficult to process materials.
3. Metals intended for the manufacture of medical and measuring instruments.

The main operations are finishing, finishing, high-quality sharpening. The roughness class of the resulting surfaces is 11 or 12.

3. Ceramic bonds. The circles with them have a diamond-nickel coating. It is applied in one or several layers. Let us list the key characteristics of tools in this category.

1. High cutting ability.
2. Low price.
3. Excellent thermal conductivity.
4. High-quality removal of chips from machined surfaces.

Such diamond wheels for metal are used for processing workpieces from:

1. germanium, sital, silicon and other semiconductor materials;
2. stone;
3. ceramics;
4. technical glass.

The main operations are cutting and finishing.

Shapes of diamond wheels for metal

Most often, 8 types of diamond wheels for metal are used.

1. Flat circles without grooves (D/N >= 1.8).
2. Rings (D/N ˂ 1.8).
3. Flat circles with one-sided relief.
4. Flat cone-shaped models.
5. Flat circles with one recess.
6. Flat circles with two grooves.
7. Cup circles (45° ˂ α ˂ 90°).
8. Cup circles (α ˂= 45°).

All of these types of instruments have their own identification numbers. Familiarize yourself with them and the design features of the devices in the table below.

Image No. 2: shapes of diamond wheels for metal

Let's move on to a detailed study of the grain size of the tools.

Reviews of Jet discs

The consumables produced by the American company Jet have earned high marks from not only ordinary users, but also professionals. What consumers love about these products is their versatility and excellent sharpening performance. The company can offer a full set of diamond discs that can be used for any abrasive operations, including with professional cutting tools.

An important advantage of Jet sharpening products is that they can be used to dress other abrasive discs. But these products also have a number of disadvantages - in addition to the high price, you need to carefully select disks by size, since the data given in the labeling does not always correspond to real indicators.

Circles Oregon

The main activity of the company is the production of sharpening discs for professionals. Therefore, it is quite logical that the basis of this manufacturer’s assortment consists of sharpening materials that are distinguished by high quality workmanship and productivity. Many users indicate in their reviews that products manufactured under the Oregon brand are quite reliable. There are owners who have been using such disks in active use for several years. Although Oregon diamond discs may need to be sharpened from time to time, this is not a difficult or expensive operation given the service life these discs exhibit.