A device for sharpening combination drills. How to sharpen a drill for metal with your own hands - homemade drawings and tools for sharpening, how to simply and correctly sharpen a tool on a machine. Types of drills and basic concepts

During the processing of hard products, drills are subject to rapid wear. The blunt working element heats up significantly and loses its strength characteristics. This happens due to the “releasing” of the metal alloy. The tool needs to be sharpened from time to time. However, this point concerns not only drilling devices.

Drills are fairly cheap products. At least the variations used at home. One way or another, it is at least unwise to purchase a new nozzle immediately after it becomes dull.

There are also factory-made sharpening agents, but this violates the concept appropriate use home tool.

Drills designed for wood processing almost never become dull. The product can only be “driven” in a resinous structure and at higher speeds. Pobedit tips, necessary for processing stone and concrete, are usually not sharpened. All that remains is to sharpen the tools for metal. Some experienced locksmiths do this work with their own hands, without resorting to the use of additional tools.

But in this case, the accuracy and quality of work may be questionable. And not everyone home craftsman has a good eye.

How to make your own drill sharpener

First you need to make a template, which will allow you to control the accuracy of processing.

Ordinary drills designed for working with ferrous metal are characterized by an edge angle of 115 to 120 degrees. If you constantly work with various materials, then you should familiarize yourself with the following information:

• textolite and plastic - from 90 to 100 degrees;
• any wood - 135;
• granite and ceramics - 135;
• cast iron, carbide bronze and steel - from 115 to 120;
• soft bronze and brass-based alloys - from 125 to 135;
• aluminum alloys - 135.

Based on this data, you can make several useful templates that will help you sharpen the drill with the highest quality and precision.

The easiest sharpening option- different bushings that are mounted on a reliable and strong base.

It is recommended to make a clip from aluminum and copper tubes, matching them to the most common drill diameters. You can also drill several holes in a block of non-solid material. The most important thing is to place a comfortable tool rest on the sharpener, which serves as a support and allows you to move the sharpening device at the required angle.

This method was actively used by our grandfathers. And for the material of the corner (sharpening machine), they used strong oak timber.

In fact, it is enough to place a workbench or table on the side of the emery - and a device for drill sharpening done with your own hands. At the same time, the level of accuracy and quality of sharpening will be extremely high.

There are many drawings for the manufacture of designs for sharpening devices. You can already resort to ready-made options or make them yourself. The most important thing is to understand the processing principle.

When processing, you should not allow the drill to rotate around its own axis. If the tool is turned even a millimeter, it will be damaged and you will be forced to grind off a certain length for additional processing.

Errors

To the most common mistakes self-sharpening drills include the following:

For that, to make the device yourself To sharpen drills, you should adhere to the following rules:

All the tools to create such a device can be found even at home or in the garage. They should be processed with a grinder, welding and a sharpener.

If you only have to drill into wood, then you don’t have to worry about the sharpness of the drill, since the drill can serve well for months and years without sharpening. But when it comes to drilling metal, the sharpness of the drill becomes very important, in other words, you can only drill through metal with a sharp drill bit. You can easily feel the difference when you take a completely new drill. Having started to cut into the metal rather quickly, with every minute the drill will plunge into the metal more and more slowly, and you will have to press on it more and more. The rate of dulling of a drill depends, in particular, on revolutions, feed rate, cooling and other factors, but no matter how hard you try, the time it takes for a drill to become unsatisfactory is measured in minutes. If the amount of work is significant, it will be expensive to constantly buy new drills, so it is better to learn how to sharpen them. Although it is still worth having several drills of the same diameter (3-10, depending on the diameter and, accordingly, the price) in order to return to sharpening only when all the drills have become dull.

At the periphery of the drill, the cutting speed is maximum, and, therefore, the heating of the cutting edges is maximum. At the same time, heat removal from the corner of the cutting edge is very difficult. Therefore, dullness begins at the corner and then spreads to the entire cutting edge. Its curve is clearly visible. Then the back edge wears off. Strokes and marks appear on it, coming from the cutting edge. As they wear, the marks merge into a continuous strip along the cutting edge, wider at the periphery and tapering towards the center of the drill. The transverse cutting edge becomes wrinkled when worn.

At the beginning of dullness, the drill makes a sharp creaking sound. If the drill is not sharpened in time, the amount of heat generated will increase and the wear process will proceed faster.

To make it easier to control the geometry of the drill, the main thing that should be done is the template described below. With its help, even if sharpening is carried out without tools, you can always check where else the metal needs to be removed, and, in the end, get what you should get (it’s impossible that it won’t work out, even if you have to grind off half the length of the drill) . To maintain symmetry, try to keep the sharpening time and pressure constant for each section.

Sharpening twist drills

There are special machines or devices for sharpening. If possible, it is better to sharpen drills using specialized equipment. But in a home workshop, such an opportunity, as a rule, does not exist. Drills have to be sharpened by hand using an ordinary sharpener.

Depending on what shape the back surface is given, there are different types sharpening: single-plane, double-plane, conical, cylindrical, screw.

With single-plane sharpening, the back surface of the pen is made in the form of a plane. The clearance angle for such sharpening should be 28-30°. With single-plane sharpening, there is a high risk of chipping the cutting edges. This method is the easiest to implement when manual sharpening, recommended for drill diameter up to 3 mm.

Universal drills with a diameter greater than 3 mm are usually subjected to conical sharpening. In order to understand the features of such sharpening, let’s consider a diagram of conical sharpening on a drill machine with a 2φ angle of 118°. The figure below shows a grinding wheel and a drill pressed against its end with the cutting edge and back surface.

Let's imagine a cone, the generatrix of which is directed along the cutting edge and the end of the grinding wheel, and the apex is 1.9 times the diameter of the drill. The apex angle is 26°. The drill axis intersects with the axis of an imaginary cone at an angle of 45°. If you rotate the drill around the axis of an imaginary cone (as if rolling a cone along the end of a grinding wheel), then a conical surface is formed on the back edge of the drill. If the axis of the drill and the axis of the imaginary cone are in the same plane, then the clearance angle will be zero. To form a back angle, you need to shift the axis of the drill relative to the axis of the imaginary cone. In practice, this offset will be equal to 1/15 of the drill diameter. Swinging the drill along the axis of an imaginary cone with this mixture will provide a conical back face and a back angle of 12-14°. The larger the offset value, the larger the clearance angle will be. It should be remembered that the clearance angle along the cutting edge changes and increases towards the center of the drill.

It is clear that it is very difficult to fulfill all these sharpening conditions manually. The drill intended for sharpening is taken by the left hand working part, perhaps closer to the fence cone, and with the right hand by the tail.

The cutting edge and rear surface of the drill are pressed against the end of the grinding wheel and, starting from the cutting edge, with smooth movements right hand, without lifting the drill from the stone, rock it, creating a conical surface on the back edge of the pen. Then repeat the same procedure for the second feather.

When sharpening, it is advisable to repeat as accurately as possible the shape of the back surface that was after the factory sharpening, so as not to lose the required back angles.

Another sharpening method widely used by home craftsmen is as follows. As in the previous case, the drill is taken with the left hand by the working part as close as possible to the intake cone, and with the right hand by the tail. The cutting edge of the drill is pressed against the end of the grinding wheel and with a smooth movement of the right hand, without lifting the drill from the stone, rotate it around its axis, sharpening the back surface. It is very important to maintain the desired angle of inclination to the end of the grinding wheel when rotating the drill. For this purpose, special bushings are often used when sharpening.

As a result of this sharpening, a tapered surface will be formed on the back surfaces of both feathers, but a relief angle will not be formed. During operation, the friction of the rear surface against the walls of the hole and, therefore, the heating will be greater.

Due to friction with the grinding wheel, the tool heats up during sharpening. This causes the hardened part of the tool to temper. The metal softens and loses its hardness. Inept sharpening renders the tool blade unusable. Therefore, sharpening should be carried out with repeated cooling of the drill in water or in a water-soda solution. This requirement does not apply to carbide drills. Do not use oil for cooling when sharpening. If for any reason the tool is sharpened dry, then:

• a small layer of metal is removed in one pass;
• rotational speed abrasive wheel should be as low as possible;
• The drill should never become so hot that the hand cannot tolerate it.

Practice shows that tool sharpening should be carried out against the movement of the grinding wheel. Then the cutting edge is more durable, and it is less likely to crumple or break off.

For sharpening, grinding wheels made of electrocorundum (grades 24A, 25A, 91A, 92A) with a grain size of 25-40, hardness M3-CM2, on ceramic bonds are used.

In production, sharpening is usually followed by finishing. Finishing makes the surface smoother and removes small nicks. A polished drill is more resistant to wear than a drill after sharpening. If you have the opportunity to do some fine-tuning, take it.

For finishing, grinding wheels made of green silicon carbide grade 63C, grit 5-6, hardness M3-SM1 on a bakelite bond, or wheels made of CBN LO, grit 6-8 on a bakelite bond, are used.

One of the main conditions correct sharpening drill - maintaining its axisymmetricity. Both cutting edges must be straight and have identical lengths and identical apex angles (and point angles) relative to the drill axis.

The correctness of sharpening is checked with a special template.

a - template; b - checking the apex angle and cutting edge lengths; c - sharpening angle; g - the angle between the jumper and the cutting edge.

It is made independently from a sheet of copper, aluminum or steel approximately 1 mm thick. The most durable template is, of course, made of steel. The template is used to check the angle at the apex, the length of the cutting edges, and the angle between the jumper and the cutting edge. Instead of the back angle, which is very difficult to measure, the tip angle is measured using a template. It is advisable to make a template before using a new drill in order to transfer the required angles from the last one.

The uneven length of the cutting edges and their inclination to the axis of the drill also lead to unequal load. The drill will fail faster due to intense wear of the overloaded cutting edge.

a - the wedges of the cutting edges are not the same, the middle of the jumper does not coincide with the axis of the drill; b - cutting edges are sharpened to different angles to the axis of the drill, the middle of the jumper coincides with the axis of the drill.

An uneven load on parts of the drill will cause it to run out during the cutting process and, as a result, an increase in the diameter of the resulting hole.

The easiest way to check the correct sharpening is test drilling. If the drill feathers are sharpened unequally, then the less loaded one will have less chips from the corresponding groove. Sometimes chips protrude through only one groove. The hole diameter may be exaggerated compared to the drill diameter.

The device consists of a fixed base and a removable holder with holes for drills of different diameters.

1 - rail; 2 - drill; 3 - emery wheel; 4 - base; 5 - holder.

The base is made of a planed board 30-40 mm thick, to which it is sewn (nailed, glued) at an angle of 30-32° (depending on the angle 2φ, see below, 30° for 2φ=120°, 32° for 2φ=116°) ) wooden slats with a side edge beveled at an angle of 25-30° (for single-plane sharpening). This rack orients the holder with the drill being sharpened at the desired angle relative to the grinding wheel. The holder is made of rectangular wooden block, one of the sidewalls of which is planed at an angle of 60-65° (depending on the angle of the side edge of the rail). With this sidewall, the holder is pressed against the rail on the base board, which ensures sharpening of the front angle of the drill within the required limits (25-30°). On the other sidewall of the holder, mark and drill through holes perpendicular to the plane of this sidewall for each drill of one diameter or another. The length of the holder is chosen so that it is comfortable to hold when sharpening drills.

You can’t install the device on a regular pad (armrest), so you’ll have to come up with some kind of table or shelf for it, you can move it sharpening machine on the table where there will be room for this device. Place a holder with a drill inserted into it to be sharpened, close to the rail, on the base. Turn the drill in the holder socket so that the sharpened edge is oriented horizontally. With your left hand, hold the drill near the edge to be sharpened, and with your right hand, hold the drill shank. While pressing the holder against the beveled strip, move the drill to the emery wheel and sharpen one edge. Then turn the drill and process the second edge in the same way.

It can be done even simpler:

Sharpening angles and other characteristics of the drill

A twist drill consists of a working part, a neck, a shank and a foot.

A - with a conical shank; B - with a cylindrical shank; a - working cutting part; b - neck; in - width of the pen; g - foot; d - leash; e - screw flute; f - feather; z - shank; and - jumper; L - total length; L 0 - length of the “working cutting part”; D - diameter; ω - angle of inclination of the “chip screw groove”; 2φ - apex angle; f - width of the spiral ribbon; ψ is the angle of inclination of the jumper.

The working part is divided into cutting and guiding. All cutting elements of the drill are located on the cutting part - the intake cone. The guide part serves to guide during cutting and is a spare part when resharpening the drill. On the feathers of the guide part along the helical line there are cylindrical chamfers-ribbons. The ribbon serves to guide the drill in the hole, as well as to reduce friction of the drill against the walls of the hole. It shouldn't be wide. Thus, the width of the drill strip with a diameter of 1.5 mm is 0.46 mm, and with a diameter of 50 mm - 3.35 mm. The drill shank and foot are used to secure the drill in the machine spindle or chuck. Drills can be made with or without a neck.

The diameter of the drill, measured by the strips, is not the same along the length of the drill. At the intake cone it is slightly larger than at the shank. This reduces the friction of the ribbons against the walls of the hole.

In order to understand the structure of the cutting part of the drill, we will consider the basic principles of operation of any cutting tool (including the drill). One of the most important requirements To cutting tool is to ensure that the separated chips move freely from the cutting site. The surface of the tool along which the chips run is called the rake face. This face is deflected back at a certain angle from the vertical plane.

1 - wedge; 2 - object being processed; γ (gamma) - front angle; α (alpha) - rear angle; δ (delta) - cutting angle; β (beta) - sharpening angle.

Thanks to this angle, it is easier for the tool to cut into the metal and the chips flow more freely along the front edge. The angle between the front edge of the tool and a plane drawn perpendicular to the cutting surface is called the rake angle and is denoted by the Greek beech γ.

The surface of the tool facing the part is called the back face. It is deflected at a certain angle from the surface of the workpiece to reduce the friction of the tool on the cutting surface. The angle between the rear edge of the tool and the cutting surface is called the clearance angle and is designated Greek letter α.

The angle between the front and back edges of the tool is called the point angle and is denoted by the Greek letter β.

The angle between the front edge of the tool and the cutting surface is called the cutting angle and is denoted by the Greek letter δ. This angle is the sum of the tip angle β and the clearance angle α.

The rake and back angles are the angles that must be maintained when sharpening.

Now let’s find the edges and angles described above on a drill, which is not at all similar to the tool shown in the figure above. To do this, we cut the cutting part of the drill with plane AB, perpendicular to its cutting edge.

Cutting edge- this is the line of intersection of the front and rear edges of the tool. The rake angle γ of the drill is formed by a helical groove. The angle of inclination of the groove to the drill axis determines the size of the rake angle. The magnitude of the angles γ and α along the cutting edge is variable, as will be discussed below.

The drill has two cutting edges connected to each other by a bridge located at an angle ψ to the cutting edges.

Having received a general idea of ​​the geometry of the cutting part of the drill, let's talk in more detail about its elements. The front edge of a twist drill is a complex helical surface. Facet is a conditional name, since the word “facet” implies a plane. The helical flute, the surface of which forms the leading edge, intersecting with the fence cone, creates straight cutting edges.

The angle of inclination of the helical groove to the drill axis is denoted by the Greek letter ω. The larger this angle, the larger the rake angle and the easier the chip exit. But the drill weakens as the inclination of the helical flute increases. Therefore, for small-diameter drills, which have lower strength, this angle is made smaller than for large-diameter drills. The angle of inclination of the helical flute also depends on the material of the drill. High speed steel drills can operate under more stressful conditions than carbon steel drills. Therefore, for them the angle ω may be larger.

The choice of inclination angle is influenced by the properties of the material being processed. The softer it is, the greater the angle of inclination can be. But this rule applies in production. At home, where one drill is used for processing different materials, the inclination angle is usually related to the drill diameter and varies from 19 to 28° for drills with a diameter of 0.25 to 10 mm.

The shape of the flute should create enough space to accommodate chips and allow them to be easily removed from the flute, but not weaken the drill too much. The width of the groove should be approximately equal to the width of the pen. The depth of the groove determines the thickness of the drill core. Strength depends on the thickness of the core. If the groove is made deeper, the chips will be better accommodated, but the drill will be weakened. Therefore, the thickness of the core is chosen depending on the diameter of the drill. In small diameter drills, the core thickness is a larger proportion of the drill diameter than in large diameter drills. So, for drills with a diameter of 0.8-1 mm, the core width is 0.21-0.22 mm, and for drills with a diameter of 10 mm, the core width is 1.5 mm. In order to increase the strength of the drill, the thickness of the core is increased towards the shank.

The front edge of the drill is not sharpened.

The design of the helical grooves is such that as they approach from the edge of the drill to the center, their angle of inclination decreases, and therefore the rake angle decreases. The working conditions of the cutting edge near the center of the drill will be more difficult.

The rear angle, like the front angle, varies in size at different points of the cutting edge. At points closer to outer surface drills, it is smaller, at points located closer to the center, it is larger. The clearance angle is formed when sharpening the intake cone and is approximately 8-12° at the periphery of the drill, and 20-25° at the center.

The bridge (transverse edge) is located in the center of the drill and connects both cutting edges. The angle of inclination of the jumper to the cutting edges ψ can be from 40 to 60°. Most drills have ψ=55°. The bridge is formed by the intersection of two back faces. Its length depends on the thickness of the drill core. As the thickness of the core increases towards the shank, the length of the bridge increases with each sharpening. During the drilling process, the transverse edge only interferes with the penetration of the drill into the metal. It does not cut, but scrapes or, rather, crushes the metal. No wonder it was once called a scraping blade. By halving the length of the bridge, the feed force can be reduced by 25%. However, reducing the length of the bridge by reducing the thickness of the core will weaken the drill.

The tip angle of 2φ has a great influence on the operation of the drill. If the apex angle is small, the lower edge of the chip will touch the wall of the hole and there will be no conditions for proper chip formation.

The picture below shows a drill with a normal taper angle.

In this case, the edge of the chip fits well into the groove. Changing the tip angle changes the length of the cutting edge and therefore the load per unit length. As the tip angle increases, the load per unit length of the cutting edge increases, and the resistance to penetration of the drill into the metal in the feed direction increases. As the tip angle decreases, the force required to rotate the drill increases, as the conditions for chip formation worsen and friction increases. But at the same time, the load per unit length of the cutting edge decreases, the thickness of the cut chips becomes smaller and heat is better removed from the cutting edges.

Typically, the point angle (2φ) of standard universal drills made of carbon, chromium and high speed steel is 116-118° and is considered suitable for many materials. But in order to ensure best conditions work, it is changed as shown in the table.

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To improve the quality of their work, craftsmen often make a machine for sharpening drills with their own hands. When using drills, you need to pay attention to their sharpness and absence of damage - the quality of drilling depends on this. Previously, sharpening was done by hand, but today you can buy a special machine or make it yourself according to individual parameters.

Features of the drilling process that affect the sharpness of drills

Drilling is ubiquitous in home and industrial settings. In this process, the cutting edges create indentations in the surface as they rotate. Their power is enough to affect most materials, and even metal. The presence of a spiral channel removes work waste and dust, so you can drill without stopping. But these particles wear out the drill device, causing it to wear out. Periodic sharpening can prevent this.

The wear of the drill directly depends on the duration of its use.

Damage occurs most quickly when working with metal and wood. The problem can be noticed when a specific squeaking sound is detected. As a result, not only the quality of drilling deteriorates, but also the heating of the tool increases, which can damage it. If the drill is heavily worn, the deterioration in sharpness can be felt even by touching it.

Types of sharpening:

• Single-plane – used for large drills. This is a strong sharpening that can crush material, so you need to be careful. The part must be moved on a circular surface without shifting its position so as not to damage the surface.
• Conical – used for large drills. They need to be held with both hands, as if you press on the part, it may slip.
• Finishing is the final stage, which smoothes out isolated irregularities and polishes the surface.

Most often, spiral alloy drills with reinforcing tips are used. There are also flat models, For large holes. Regardless of the parameters and diameter, they require sharpening to prevent wear.

What will you need to assemble a drill sharpening machine?

Not only the grinding is responsible for the cutting ability of the drill, but also the angle of the blades - the smaller it is, the better the drilling. Optimal angle 90° is considered, 100° is required for wood, and 30° is suitable for plastic. Sharpening improves the angle of the cutting edge and centers it. This is done with sanding, which is also used in specialized equipment or for manual sharpening. Machines can be industrial or household, which determines their dimensions and power. Many craftsmen create their own sharpening equipment - this is a cheap solution, often as good as a production model.

It is best performed on special machines. Modern market offers big choice such devices, but their parameters do not always meet expectations or the cost is too high. In this case, you can make the machine yourself; this requires only basic technical skills. Despite the lower power home machine, it has a number of advantages compared to industrial devices:

• use of single-phase electricity flow at 220V;
• individual performance tuning;
• mobility of equipment when installing limited functionality;
• high performance for required type drill;
• ease of repair and low assembly costs.

The right approach to creating a machine will allow you to obtain an effective sharpening apparatus. To assemble it you need a toggle switch, a plug, a grinding wheel, a fairly strong motor, a set of wires, a stand and an axle. It is important to observe safety precautions, so it is better to cover the machine in a protective case, leaving only the turning circle and the axis visible. To operate the device, they use both a constant power supply and a battery for greater mobility.

Assembling parts into a single device and installing safety elements

It is necessary to provide a surface for mounting the machine. A metal table is suitable for this, on which marks are made for the bolts. Next you need to take a granular disk, which is attached to the electric motor of the future machine. If the diameters of the shaft and disk do not match, they must be aligned using available tools. If there is a match, the washer is placed on the shaft, after which the disk and, again, the washer. The shaft must first be threaded. Next, install the fastening nut, and put the anti-sway attachment on the circle.

You can add a bushing if the shaft has a smaller diameter for the stone. A hole is made in it, with which it is attached to the shaft, since the bushing will improve fixation and will rotate together with the disk. If you cannot choose the right electric motor, you can use a motor with washing machine. Wires can also be installed from it if they have three contacts in suitable condition. Next, the winding is connected to the phase line of two buttons responsible for turning the machine on and off. Thus, the device will be triggered by simple button commands.

The electric motor does not pose any danger open form, but he should provide protection. The motor can be hidden in a metal casing so that dust does not accumulate and moisture does not penetrate. Since a lot of chips are released when sharpening drills, this creates a danger. Need to build protective screen made of glass that will protect your eyes. Of course, you can use glasses, but metal particles may fly into your face. It is also advisable to make a protective casing. A tire is suitable for this, part of which will cover one third of the sharpening disc.

Sharpening parts on a homemade machine

If you can’t get an electric motor, you can get by with a simple drill. It is not necessary to buy a new device; an old device in which the engine operates will also work. To create a machine, you need to fix it on the surface, and install a universal disk (can be replaced with a grinding wheel) or bushing in the chuck. When you turn on the drill, it will be suitable for working on drill bits. To achieve best efficiency, you need to approach the sharpening process correctly. Since drills have two threads, it is important to maintain the same dimensions when machining them so that the axis of rotation corresponds to the center of the drill.

Before you start sharpening, you need to check that the disc is securely fastened and protective elements. It will take half an hour to quality results. Each drill material has its own sharpening characteristics and rotation direction, which must be studied before work. IN table machine a sharpener (abrasive disc or emery) of the coarsest format is installed. This will correct the main damage. After this, you need to switch to a fine abrasive that will grind the surface. It is important to maintain one sharpening angle, although the drill moves out in the process. If this is missed, there is a risk of dismounting and injury.

It is important to avoid overheating of drills. This destroys their plates, so you need to periodically immerse them in water (this cannot be done if the drill is already hot). Otherwise, simple skill is enough to sharpen drills. Following the procedure and safety rules will allow you to quickly sharpen drills to homemade machine and do without expensive equipment.

Metal drills are hardened during production, but gradually they still become dull. Of course, you shouldn't throw them away right away. You can sharpen a metal drill yourself using special equipment.

Types of sharpening devices

To properly sharpen a drill, you need to use special devices. They are divided into two categories:

• industrial equipment. Has high power. Using it, it is possible to sharpen drills with a radius of one centimeter. These devices are installed in large enterprises. Sharpening is performed semi-automatically/automatically;
• household equipment. Intended for use at home. In addition, it is used in small enterprises. This equipment is mobile, compact, and has standard power.

When purchasing a machine, you need to take into account the noise level, design features device. It is optimal to buy a regular machine, because it is easy to find suitable spare parts for it.

You only need to purchase sharpening devices in special places, because they come with the machine technical certificate. In addition, the buyer receives a warranty card.

Use of sharpening machines at home

For home the best option are considered household machines. With them it is possible to sharpen different types drilling tools. It is worth considering that for certain types of drills you will need to buy special wheels.

In order to carry out sharpening yourself, you need to choose a machine that is equipped with a universal chuck. It makes it possible to clamp parts of different sizes.

The buyer is often provided with the sharpening device:

• CBN circles;
• keys;
• collets;
• replacement parts;
• lighting fixture for the workplace.

The most common devices for sharpening drills are Drill Doctor, GS. These machines are intended for sharpening drilling tools with a radius of 0.2-3.4 cm. Such equipment is unable to sharpen extremely thin objects. To do this you will need to buy a special machine.

All equipment intended for sharpening tools at home:

• can work from the electrical network;
• highly productive;
• easy to use;
• functional;
• provides precise sharpening;
• is inexpensive;
• compact;
• weighs little;
• conveniently controlled. It is possible to change the intensity of sharpening and its speed.

How to make your own sharpening machine

First of all, you need to purchase a control device. It is required to check how accurately the work is done.

For drills intended for machining various metals, you need to make a different edge angle. Below is a list of machined parts and corresponding edge angles:

• steel, cast iron, bronze – 115;
• brass, copper – 125;
• aluminum, ceramic, granite, wood – 135;
• magnesium – 85;
• silumin, plastic, textolite – 90.

Having familiarized yourself with this list, it is possible to make several templates and, accordingly, carry out sharpening with your own hands. The same drilling tool can be used for different parts. You just need to change the angle of the vertex of the workspace.

A simple but very effective device for sharpening a drill is the base on which the bushings are attached various sizes. Remember that the object should not shake in the sleeve. The slightest deviation will lead to a significant decrease in the quality of drilling processing.

It is advisable to have a tube holder made of aluminum/copper. You can also make it in a block from soft material the required number of holes. Mount on grinding wheel Convenient hand grip that allows you to move at the required angle homemade device for sharpening drills, serving as a thrust element.

Currently, there are various drawings of sharpening devices. You can use an existing one or create your own. Do not forget that when sharpening a tool, you must not allow the drill to rotate around its own axis.

Once sharpening is complete, allow the tool to cool. Measure the accuracy of your work using a template. The edges should be symmetrical. This is especially important for small radius tools.

Using an electric drill

Some people prefer to use an electric drill, which is equipped with special attachments, as the basis for a sharpening device. Of course, the number of attachments is limited. Consequently, sharpening by hand is difficult. The set with attachments includes a stone and a leash.

If you want, you can make the nozzle yourself. This element of the sharpening device must be equipped fastener for fixing the tool.

Features of sharpening

If you decide to sharpen the tool yourself using sharpening devices, carry out the procedure according to the following algorithm:

1. Finish the rear. Press the tool firmly and make sure that the sharpening angle does not change. At the end of processing, the end of the tool will look like a cone.
2. Now sharpen the cutting surface.
3. At the final stage, the rear part is refined. Make sure that the jumper size does not exceed four tenths of a millimeter. Of course, for a large instrument this figure should be slightly higher.

If something doesn't work out for you, don't be upset. It is advisable to practice on drills that most likely will not be useful. The main thing is to learn the correct pressure and maintain the angle. Remember that the holes are drilled into the sides of the tool, not the tip. Therefore, the edges must be sharpened to mandatory.

Do not forget that when processing a drill, tiny particles appear. Due to heating, they fly into different sides. In view of this, safety rules must be observed. Use special glasses and gloves. In addition, make sure that the tool is securely fastened, otherwise it will fly out of your hands.

If you want to use a device for sharpening drills with your own hands, be sure to prepare work area. Make sure there is adequate lighting. In addition, do not forget to wear special gloves and safety glasses.

1. First of all, calculate the desired sharpening angle.
2. Your sharpening stand should be such that the grinding wheel is on the right side.
3. Perform alignment. To do this, grab the work area with your thumb and forefinger and hold the tail edge with your other hand.
4. The drilling tool must be rotated so that the cutting surface is parallel.
5. Don't forget to remove nicks and other imperfections.
6. All movements must be done in some order. Eg, left hand it is necessary to move to the bottom from the left side, and the right - clockwise.

Conclusion

Purchasing industrial equipment for sharpening drills is not very rational, since it is expensive. For home needs, an ordinary household machine or a sharpening device made by you is optimal.

To avoid mistakes when sharpening a metal drill yourself, you need to use special device. This can be a household/industrial machine tool, an electric drill with a special attachment. The attachment fits directly onto the drill for sharpening drill bits. If you haven't attempted sharpening a drill bit before, watch the instructional video below.

Be sure to follow safety precautions. Ignoring simple rules, failure to wear protective clothing can land you in a hospital bed. Sparks caught in the eye are no joke. There is a high probability of losing your vision completely. Agree, it is better to simply wear special gloves and safety glasses than to expose yourself to the risk of serious injury.

The quality and accuracy of drilling depends on the sharpness of the working tool. Moreover, unlike table knife, the drill must be sharpened correctly. Experienced mechanics can straighten the 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 a 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 has small size, therefore, 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 is not as intense. 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 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. An additional bonus is that 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 large diameter drills). Linear movement (along the axis) can be controlled by the master, or a limit stop can be installed.

From the point of view of processing quality, the device has practically no shortcomings. But for proper sharpening, the operator must know the parameters of the drill. 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 tabletop sharpening machine.

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 extra financial costs. In addition, there are replaceable attachments for hand-held power tools (for example, a drill). But this is a topic for another article.