How to sharpen drills without much effort and skill right angle sharpening? Unfortunately, many of us do not succeed the first time. This device is very simple in design. Therefore, each of you will be able to repeat it. Many people know that the edges of bolts and nuts have the same angle as a standard drill sharpening. We will use this. We will not weld two nuts together to get the correct pattern. The design is a little different.
To start, you need any nut. The larger the diameter, the larger the diameter of the drill that can be sharpened in it.
The nut has 6 faces, 2 of which we need. Take a caliper and mark 4 mm from the edge of the nut. We turn the nut the other way around and make a mark on the edge that is one and a half mm larger than the first one. We make a triangle on 2 sides. Cut with a hacksaw or grinder. The result was a nut with cuts.
We weld another one. The device is almost ready. He misses the puck, which we throw into the middle. You will also need a bolt; it screws into a small nut.
The cuts in the nut have different depths, which differ by 1.5 mm. This difference is hardly noticeable to the eye. We insert the rod, fix it, and apply a ruler. The gap between the ruler and the round timber is smaller on the left than on the right. That is, the device has a certain angle. Where the gap is smaller, the master made a mark.
Operation of the device mechanism
We take a straight, unsharpened drill and place it in the device. Where the mark is, the drill must be placed, as shown in the photo and video. We fix the drill so that it protrudes slightly from the edges. The drill will be sharpened on the working side. In the example shown, it is possible to clamp with a diameter of up to 8 mm.
When we start grinding the edge of the drill using sandpaper, there is a guide in the form of the plane of the edge of the nut, which sets the correct sharpening angle.
This is a great device for those who cannot find the right angle by eye.
The video shows how to position the tool relative to the sanding wheel. From the 6th minute you can see how the drill is processed.
Alexander Polulyakh.
In addition to this video tutorial, another DIY device using bolts and nuts.
Drawing
https://drive.google.com/file/d/0B8iB5ht2WrqOMEJiZlRtZ2VWdVE/view
To quickly and efficiently drill holes, you need sharp drills, which tend to become dull over time. Best of all, this tool sharpens the machine for drill sharpening. You can also use special devices at home.
1
A drill sharpening machine is a highly specialized automated equipment designed only for sharpening drills. According to the area of use they distinguish the following types these devices:
- Industrial - have more power, various drills with a diameter of 20 mm or more are sharpened on them. The main purpose of such equipment is intensive work at large enterprises with a high degree of specialized specialization. In industrial equipment, the drill is sharpened in a fully or partially automatic mode at the desired angle using a fastening unit (special clamp).
- Household - used exclusively in small industries or at home. The design of these machines is characterized by low power, compactness and mobility. They can be used to sharpen medium and small size which are used most often in everyday life.
A household machine for sharpening drills has a lot of important advantages over all other devices and devices used to restore the sharpness of a tool, among which the following are worth noting first of all:
- operates from an electrical network with standard voltage;
- high degree of productivity;
- ease of operation;
- high level of sharpening accuracy and functionality;
- affordable price, located in permissible limits possibilities of any home handyman;
- has a light weight and compact size;
- comfortable ergonomic system control provides regulation of the speed and intensity of sharpening.
2
All household machines are designed for sharpening high-speed steel of a certain diameter range of equipment that is structurally incorporated into the device. On many machines, you can sharpen tools equipped with carbide inserts - for this, a diamond wheel is supplied or additionally purchased. Typically, their capabilities include sharpening drills with a cone angle at the apex in the range of 90–140° along the back surface with backing and sharpening of the cutting transverse edge. But specialized modifications for metal drills are also produced:
- left;
- with a two-plane backing;
- high-performance;
- three-pronged;
- others.
Most convenient in home use machines with a universal chuck for clamping drills of various diameters within the technically acceptable range of sizes, as well as devices equipped with a set of removable chucks that are mounted on the body of the machine itself and are always at hand.
Such equipment is usually equipped with a window through which you can observe the centering of the drill in the working area of the machine. The machine comes with standard accessories: CBN wheels, a set of collets, keys, spare parts. Additional accessories can also be supplied: diamond wheels, an additional set of collets, a lamp for working area and others. Most known types similar machines: Drill Doctor, G.S. and their Chinese counterparts.
According to the range of sizes of drills processed, these machines are produced in two main types (with different extreme diameter values): from 2 mm to 13 mm and from 13 mm to 34 mm. Their disadvantages: poor sharpening of thin drills (the precision of the machines is not designed for this) and the inability to sharpen very thin ones. For tools of small diameters, you will need a special machine for sharpening drills - for example, VZ-389SP, designed for sharpening tools measuring 0.4–4 mm and equipped with a 30x optical device to control the sharpening process.
3
Before choosing a machine for sharpening drills, it is necessary to determine the future scope of work for it, because when purchasing you need to be guided by certain operational parameters . If the device is intended to be used at home (for example, in a country house or garage), then you can purchase a low-power, inexpensive model– taking into account that the machine will not be in constant use, the equipment high power it will be completely useless. In addition, industrial devices are designed for sharpening drills of large diameters and consume much more electricity than household models.
When purchasing a machine, please pay attention Special attention for the presence of a special regulator designed to adjust the spindle rotation. This option will make work as efficient and safe as possible.
Another quite a few important parameter– the size of the drills, which should be determined by the range of intended work. The household machine you choose should have enough low level noise produced, especially when the equipment is planned to be used not in a separate room, but directly in a residential area.
It is also necessary to pay attention to the design of the model you like - it is best if it is as simple as possible. In this case, any breakdown will not cause much trouble - it will not be difficult to find and purchase the necessary new part and install it in place of the failed one. It should be noted that most foreign models in terms of their Maintenance They are quite expensive, and finding the right replacement part can sometimes be difficult. AND last recommendation: you should choose a machine for sharpening drills only in specialized retail outlets and stores where a warranty card and technical passport will be issued.
4
At enterprises, in some cases, the driller sharpens the drills himself manually on conventional sharpening machines that are equipped for this purpose special device. To do this, he must first study the rules for sharpening drills and take special preparatory courses. The drill sharpening device used is steel structure, equipped with a movable clamp for a drill with an adjustable angle of inclination relative to the rotating grinding wheel and having a mount for fixing on the body of the sharpening machine.
There are also frequent cases when an enterprise does not use any devices at all when sharpening by hand on a conventional sharpening machine. In this case, the drill right hand hold by the shank, and with the left hand - as close as possible to the cutting part. The cutting edge of the tool is pressed against the side surface of the abrasive wheel and at the same time the drill is gently rocked with the right hand, trying to ensure that its back surface accepts the required form and acquired the correct slope. You need to remove the metal in small layers, lightly pressing the tool against the circle. It is necessary to ensure that the cutting edges of the drill are the same length and have the same sharpening angles.
Mistakes made during manual sharpening, can lead to the following drill defects:
- cutting edges of unequal length;
- the angles formed by the cutting edges with the tool axis are different;
- The cross blade has a one-sided groove.
As a result of these defects, the drill will:
- beat;
- incorrectly, one-sidedly loaded on the cutting edges - may break;
- drill holes larger in diameter than the drill itself.
After sharpening the tool, you should check the width of the transverse edge and the correct position relative to the cutting edges, the length of the latter, the angle: in plan φ, the inclination of the transverse edge, the clearance angle α, double sharpening φ1, at the apex 2φ. To check all these parameters, enterprises use special templates. The correct location of the jumper is determined using an optical device. In some cases, enterprises check the runout of the drill - they use a special device for this.
Metal drills from high speed steels sharpened on grinding wheels made of white and normal electrocorundum on a ceramic bond with a grain size of 16–40, hardness SM, as well as on wheels made of CBN. When sharpening tools equipped with carbide inserts, synthetic diamonds are used, as well as green silicon carbide with a grain size of 16–40.
5
Not having special machine, at home you can use the following equipment to sharpen drills:
- ordinary sharpening machine;
- electric drill;
- homemade sharpening devices.
To use a simple sharpening machine, it is better to purchase a special device, because before you yourself learn how to properly sharpen a tool without it, you can ruin more than a dozen drills. This device for sharpening drills has approximately the same structure as the industrial one described above. There are options not with mounting on the machine body, but with separate installation on a horizontal surface near the rotating grinding wheel. Such a device can be homemade. It can be made of wood: a beam with several holes for the diameter of the required drills, drilled at an angle, ensuring the desired sharpening angle, is attached to its base. It is possible to provide for a change in the inclination - the sharpening angle.
In the case of an electric drill, a special attachment is used for sharpening drills. Unfortunately, they are available on sale only for sharpening at an angle of 118° and only for tool sizes of 3.5–10 mm (domestic) and 2.5–10 mm (imported). Moreover, both of them are only for drills with a spindle neck with a diameter of 43 mm. The body of these attachments has 15 holes for drills of different diameters. The attachments are equipped with a stone, the sharpening surface of which is located at a certain angle, and a leader for it, inserted into the drill chuck.
By changing the length of the leash once (shortening it), the attachment is configured to work with one specific drill. They work with it as follows: a leash with a stone at the end is inserted into the drill chuck; the nozzle is put on the spindle and secured with a screw; start the drill and insert drills into the hole of the nozzle body of the appropriate diameter. You can also make such a device yourself. IN homemade nozzle it will be possible to provide the required sharpening angles and tool diameters.
Homemade devices can be made in the form of conventional sharpening machines. It is better to immediately provide a method for attaching and sharpening drills, so as not to invent additional accessories for this.
The quality and accuracy of drilling depends on the sharpness of the working tool. In addition, unlike a table knife, the drill must be sharpened correctly. Experienced locksmiths can level cutting edge on a regular sharpening machine, simply holding the drill in your hands (at least according to them). But this method requires skill and many years of experience. Even if you have steady hand, and an excellent eye - without understanding the process, you will simply ruin the instrument.
A few basic rules for sharpening (using the example of twist drills for metal):
For a better perception of the material, let’s remember the structure of the drill.
- Do not press the tip against the sandpaper for more than 2-3 seconds at a time. The metal heats up and the so-called “tempering” occurs, that is, deprivation of hardening. Accordingly, the necessary hardness of the metal is lost. The first sign is the presence of temperature discoloration on the edge.
- For drills with a diameter of up to 4 mm: each time the sandpaper plane touches the drill, the drill is held in one position: rotation around its axis is not allowed. For larger diameters, the sharpening geometry is slightly different.
- On twist drills, only the back surface of the cutting part is sharpened.
- The cutting edge should be directed towards the rotation of the sharpener (for mechanical sharpening).
- The main angle (2φ in the illustration) depends on the type of material being processed.
Which drills should I sharpen and how often?
Feather and other special wood drills cannot be repaired at home, and they do not become dull so quickly. Pobedite tips for concrete cannot be sharpened in principle. The most popular tool remains - twist drills for metal. Of course, they are also used for processing wood (plastic, rubber and even stone), but this is not relevant to the topic.
Twist drill. The cutting edge is small in size, so during operation it quickly heats up due to friction (there is no dissipation area). The main reason for dullness is overheating. At correct use wear does not occur as intensely. Characteristic signs blunt drill:
- A creaking sound is heard during operation.
- Instead of curled shavings, sawdust comes out of the hole.
- Instant heating of the tool without moving deeper.
Important: Do not use a dull drill; wear from overheating will only progress.
So, it's time to sharpen the tool. You don't want to ruin the drill and want to mechanize the process.
Mini sharpening machines are at your service:
All devices are divided into two types: attachments or stops for universal tool, And independent devices narrow specialization. Let's look at the most popular of them, from simple to complex:
This is just the device for those who have a steady hand and a diamond eye. In fact, it only allows you to hold the drill in a given position without fear of injuring your fingers. Angle control is visual, according to the position of the “wings” relative to any landmark. There are few advantages: instant readiness for work, compactness and price. The disadvantages are obvious: manual control of the process does not add accuracy.
In fact, this element is not a special device for drills. It simply allows you to fix the tool at a certain angle. The accuracy will be higher than in the previous version. Most stops allow you to set the angle of inclination, and even have a marking scale. And yet you have to rely on firmness of hands.
There are also more advanced stands: with replaceable elements and adjustment of not only the angle, but also the height. The devices are mounted not on the emery body, but on the workbench: which makes them more universal.
In fact, such a stop can be adapted to any electric sharpener. Extra Bonus– with the help of such a stand you can sharpen knives, cutters, screwdrivers, chisels, etc.
Semi-professional guides for all types of drills
This is a fairly advanced tool that allows you to control sharpening characteristics with micron precision. All linear parameters are securely fixed, the values are set according to the markings. The drill is mounted in the groove, accidental displacement or rotation around its axis is excluded.
For sharpening, the possibility of both linear movement and movement of the edge along the arc path is provided (for conical sharpening of drills large diameter). Linear movement (along the axis) can be controlled by a master, or a limit stop can be installed.
From the point of view of processing quality, the device has practically no shortcomings. But for correct sharpening the operator must know the drill parameters. That is, there is no automation: therefore the tool belongs to the professional category.
As a development of the line - a guide with its own sharpening unit. There is no need to install a stop on the workbench and change discs. In fact - you have a semi-automatic table machine for sharpening.
Important note: All listed devices are designed to work with standard electric sharpeners. Therefore, before starting to process drills, it is advisable to install a special emery disc.
They are specialized power tools for performing a single task: sharpening twist drills.
Even a person who is far from technology can use the machine (although why does he need sharp drills?). The operator only needs to determine the diameter of the drill and immerse it in the appropriate hole. It is convenient to work, errors are practically excluded. However, all drills are sharpened with the same comb. The price to pay for ease of use is the lack of flexibility in settings. For home use – the best choice: especially if there is an additional attachment for sharpening knives and scissors.
There are versions for masters. The drill is installed taking into account the sharpening parameters, the process can be controlled by the operator.
The sharpening angle, the method of edge processing (linear or conical), and the depth of metal removal are selected. The drill is not located in a common holder, but in an individual cartridge.
Industrial sharpening equipment for a metalworking shop
During intensive use of drilling machines, a separate post is required to restore the functionality of the tool. Professional stands for sharpening drills of any diameter save time and effort, but the cost of such equipment is too high for home use.
The information obtained will help you choose a sharpening device, without unnecessary financial costs. In addition, there are replaceable nozzles for hand power tool(for example, a drill). But this is a topic for another article.
For smooth operation, accurate and centered drills are required. We suggest you consider where you can buy a machine for sharpening drills, how to do it homemade unit, as well as how household models differ from industrial ones and what their price is.
Types of drills and basic concepts
There are several types of drills, because They are divided according to the principle of operation and the relationship of the working surfaces; they also need to be sharpened in different ways; let’s get acquainted with the main ones:
- spiral. Used in almost all types of industry, household work ah, repairs, etc.;
- flat is more narrow profile tools, they are mainly used when drilling holes of large diameters; they got their name due to the flat working edge, which is very similar in shape to a reamer.
Let's consider the fundamental provisions for sharpening twist drills and countersinks:
During the movement of the cutting surface in the material, chips are formed inside the processed raw material, this process is especially evident in the front surface. It is the large accumulation of chips that plays the main role in the deformation of the plastic parts of the drill: during operation it heats up, and under the influence of the sharp ends of the chips, its working edge changes. Of course, there is a huge difference in the speed of this process, the most dangerous and toughest is copper and steel.
Photo - Cleaning the drill from chipsDrilling is carried out according to the following scheme: during operation, a conical surface is described; this shape is also acquired by the working surface of the drill; accordingly, the cutting edge becomes somewhat blunt and changes its center. All corners of the working surface must be located above the surface of the end, this is the only way to ensure a normal and standard clearance angle.
The simplest and effective way How to sharpen a drill at home is to use an electric sharpener. You can work with a regular sharpening bar made from a mixture of abrasive materials, but such a process will take a lot of time and effort, unlike operating a device with an electric motor. A universal manual grinding apparatus has a motor whose speed is 1500-2000 min -1. Optimal power: up to 300 Watt. Such models are available from Doctor, Vollmer, Sturm, Proxxon, Drill and Weinig.
Photo - Sharpened drills Orientation is carried out along the cutting edges; you must act strictly in the direction of the spiral grooves, because they do not change their shape even from exposure large quantity shavings. We fix the drill so that the edge that will be sharpened is strictly parallel to the axis grinding tool. The most important question: when is the working part sharpened? As soon as you see a reflection of light from the working surface, this means the edge has been sharpened. Using the same system, we sharpen the second side.
Photo - Sharpening drills In this case, it is very important not to miscenter the drill earlier, in which case you will lose its balance, and during operation the tool will deviate by several degrees from the standard parameters. The angle between the lumps is the most important sharpening parameter.
Photo - Cutting angle Standard sizes have the following form:
Alloy steel, structural, tool - 90 degrees;
Soft metals (copper, aluminum, aluminum alloys) – 90-100 degrees;
Wood, plastic, rubber – 90-100;
Bronze, brass – 110-120.
In order to achieve high processing accuracy with your own hands, you need to pay special attention to standard and deformed parameters. To control the sharpening process, you can order a special drill template with the required diameter and angle. The photo shows a diagram of processing a drill with such a device.
Photo - Sharpening template If you don’t have the money or time to purchase a template, use the “old-fashioned” method: we follow the rule of left-hand mechanics. We bend our hand and place it over the drill in such a way that the cutting surface is closed on several sides, we should get a kind of corridor. We place a lamp opposite the end surface and check the evenness and accuracy of sharpening (this will be clearly visible from a distance of 20 cm from the drill, if you look with one eye).
Photo - Left hand rule 
Photo - Glare check When using a homemade electric machine, it is very important to control the drill sharpening processing process. To completely violate the accuracy, it is enough to make a mistake of 1 mm. The automatic sharpening device for small diameter core drills can also be used for discs, knives, scissors, chains, etc.
Video: Grinding machine Energomash TS 6010S
Professional ways
The methods listed above are suitable for home narrow-profile use, but if you need to sharpen drills serially, then you will not have enough time or effort for manual centering, checking or sharpening. Let's look at how a professional drill machine is used.
The grinding wheel should be made of fine abrasive material. The sharpening area should be illuminated at the correct angle in relation to the drill. The employee must wear safety glasses and gloves.
Step-by-step instruction:
Before choosing a machine for sharpening drills, you need to read reviews about it, carefully study the passport and capabilities. One mechanics forum even advised to always carry a drill with you so that you can check the effectiveness on the spot.
Price overview
Buy inexpensive machine for sharpening drills in Ukraine, Russia or Belarus - this is real, the main thing is to choose the desired model(for metal, wood or plastic), caliber (dd750хibm, drillgrind, edbs2001 - universal), and power. We suggest considering the average prices for such devices:
Nowadays desktop and universal machines brands such as DrillGrind, Sturm (produced by Energomash), BSG, BSM, ESM, MICRA, V391, Diold, EZS, NKCH. They can be found in a professional store, on the Internet, on forums in the “Selling electrical appliances” section. The main thing is to make sure that the documentation matches the data stated by the seller.
When working with hard workpieces, the working surface of the drill wears out quickly. A dull drill becomes very hot and loses strength. This occurs due to the “releasing” of the metal. The tool must be sharpened periodically. However, this applies not only to drills.
Drills are inexpensive devices. In any case, those models that are used in household. However, it is wasteful to buy a new tip every time it becomes dull.
There are factory-made sharpening devices, but this violates the concept of economical use of home tools.
Wood drills practically do not become dull, except that the tool can be “driven” at high speeds into a resinous workpiece. Pobedit tips for concrete and stone cannot be sharpened. All that remains is to sharpen the drill for metal. Many experienced locksmiths carry out this procedure with their own hands, without any equipment.
However, the accuracy of the work leaves much to be desired, and not every home craftsman has such a professionally developed eye. In any case, minimal mechanization is necessary.
IMPORTANT! Sharpen tips using a file, needle file, or even sandpaper- meaningless. To do this, you need an electric sandpaper (sharpener).
How to make a homemade device for sharpening drills?
First of all, you need to acquire a means of control. No matter how you sharpen the drill, you need a template to check the accuracy of the work.
Conventional drills for working with ferrous metals have an edge angle of 115-120 degrees. If you have to work with different materials, check out the table of angles:
Workpiece sharpening angle Steel, cast iron, carbide bronze 115-120 Brass alloys, soft bronze 125-135 Red copper 125 Aluminum and soft alloys based on it 135 Ceramics, granite 135 Wood of any species 135 Magnesium and alloys based on it 85 Silumin 90- 100 Plastic, textolite 90-100
Knowing these values, you can prepare several templates and, in accordance with them, sharpen yourself. In this case, you can use the same drill for different workpieces, you just need to change the angle of the top of the working area.
The simplest, but very effective sharpening device is bushings of different diameters, mounted on some kind of base.
Schematic drawing of the device in the illustration:
IMPORTANT! The tool should not dangle in the sleeve; an error of only one degree will reduce the quality of drilling.
It is best to make a whole clip of copper or aluminum tubes, to fit standard drill sizes. Or drill into a block of soft material enough holes. The main thing is to install a comfortable tool rest on your sharpener, which will allow you to move the sharpening device at the right angle and serve as a reliable support.
Our grandfathers used this method. Only an oak block was used as a material for the manufacture of a sharpening machine - an angle.
In principle, it was enough to place a table or workbench opposite the side surface of the emery - and the sharpening machine was ready. At the same time, the quality and accuracy of processing was at high level.
There are different drawings of sharpening devices.
You can use a ready-made one, or develop it yourself. The main thing is to understand the principle of working with a drill.
IMPORTANT! When working on a sharpener, do not allow the drill to rotate around its axis.
If the tool turns even a millimeter, it will be damaged and you will have to grind off some distance for reprocessing.
After finishing sharpening, let the drill cool and take measurements using a template. Both edges must be symmetrical to within tenths of a millimeter. This is especially important for small diameter drills.
The diagram shows typical mistakes self-sharpening:
The design of a sharpening machine for twist drills for metal, made from scrap materials
The basis is taken from household grinder with the proud inscription “made in Germany”, having all the signs of a product from the Middle Kingdom. However, it works properly, there is no axle runout, and it maintains speed under load.
Technical task the following is supplied:
- the tool rest must be strictly on the same horizontal line (or above it) with the axis of rotation of the emery;
- the design is durable and reliable, ensuring work safety;
- It should be possible to sharpen both manually and semi-automatically - using a device;
- The shape of the tool rest allows you to freely lower the drill shank to the required angle.
No scarce parts are required to manufacture the device. All the materials were actually lying underfoot in the barn. The processing of the workpieces was carried out with a grinder, the same modernized sharpener, and welding.
Since the emphasis was supposed to be made swinging (for semi-automatic mode), it was made loop connection. The holes of the tube, bracket and bolt are precisely selected to ensure there are no backlashes. The resulting device has two degrees of freedom.
The platform can be rotated along the vertical axis - changing the sharpening angle of the drill. This axis is fixed. The tool rest can also swing based on a horizontal axis, ensuring proper articulation during sharpening. This degree of freedom is not fixed.
For the base plate, metal with a thickness of 4 mm was chosen, the remaining structural elements were 3 mm thick. The strength is more than sufficient. The tool rest is rigidly connected to the emery body. Of course, attach it to protective casing is unacceptable, so we screw the bracket using an additional metal “cheek”.
The actual guide plate for drills is screwed to the tool rest (more precisely, to the support plate). The plate is 5 mm thick and has a triangular groove cut into it for fixing the drill during processing.
The rotation angle of the structure is 90 degrees. This will ensure sharpening in any way, from the Leontiev method - to pressing at one angle with the development of an acute angle of the edge due to the curvature of the sandpaper.
The drill bit being processed is not only firmly held in the groove - it can be freely fed to the abrasive along the groove, without the slightest deviation of the sharpening angle.
Due to the slight excess of the plane of the base plate above the axis of rotation of the disk, the optimal shape of sharpening the back of the working edge is achieved.
Before starting work, press the drill against the plate and align the cutting edge parallel to the plate. This completes the adjustment and you can move the tool to the sandpaper. Sharpening a drill requires certain skills; do everything slowly, carefully pay attention to the sharpening angle.
The accuracy of the work is the highest; a template is actually not required. It takes some time to install the device and adjust the angle, but you can quickly sharpen a couple of dozen drills without spending any effort.
If you need to sharpen a drill with a carbide attachment, the swinging plate can be fixed at a fixed angle. To do this, you just need to place a couple of washers under the axle nut.
A few words about the emery wheel
Typically, for universal tasks, a white corundum wheel is used in a home sharpener. It sharpens knives, axes and shovels very well. It can be used to quickly process metal workpieces.
When sharpening carbide drills (and high-speed metal also requires a harder disc), green is used abrasive wheel made of silicon carbide. Such circles are marked 64C.
The grit size for household work is usually 25H.
When sharpening drills, a finer fraction is required; it is better to work in the range 8H - 16H. It must be remembered that silicon carbide sandpapers become very hot during operation. Therefore, you cannot keep the drill in contact with the abrasive for a long time. After 2-3 approaches, let the metal cool. It is best to cool it with water and soda.
IMPORTANT! The direction of rotation of the abrasive determines the quality of the edge. Working surface the disk should run over the cut, that is, move from top to bottom.
The peripheral surface of the emery, as the main processing surface, must be perfectly flat. You can straighten it with a CBN nozzle. For discs of small diameter, it is quite possible to get by with pliers that hold the CBN cutter.
