Homemade fixture for sharpening conical drills. Adaptation for sharpening drills with your own hands. Features of sharpening on a simple device

You can easily make a device for sharpening drillsand on metal with your own hands. This will require some time and several basic elements for the future design.

The devices used for sharpening drills for metal, wood, plastic and other material are divided into two types:

Specialized. They can sharpen only one specific type of cutting tool;
Universal. With their help, all sorts of cutters, drills for metal, wood, etc.

If we talk about the manufacture of a device with your own hands, here usually craftsmen try to make a universal model. The device is obtained user-friendly and efficient for sharpening the drill of small and medium diameters. For household purposes, it will be perfect.

Elements of devices

To make a sharpening device, you will need some elements and tools:

Stand;
Tublings to turn on / off sharpeners;
Disk for a grinder;
Electric motor;
Electrical cable to connect the device to the network;
Plugs;
Material for hull.

All components of your machine for sharpening the drill will be located inside the housing. So you will be able to improve your own safety when working with grinding equipment.

Collecting the design, be available. Leave the pulley from the electric motor, since it is put on it for sharpening. It is advisable to pre-select a stationary place for the machine, because it should be fixed on the workbench or desktop.

The process of assembling the grinding device itself is as follows.

Install the electric motor at a predetermined place.
On the table, where the device will be located to sharpen metal drills, apply markup for fastening.
Electrodel Make holes on the markup under the mounting bolts.
Secure the electric motor with metal clamps at its rightmost place.
Fix the casing that will play the role of protection.
Install a grinding disk on the electric motor pulley.
The engine itself must have an elongated pulley, as it will be more convenient when operating a sharpening device. Do not forget to fit the puck before installing the circle.
If the diameter of the pulley and circle did not coincide, you can use the transition sleeve. Side of the sleeve is drilled by a hole under the thread, which is then mounted an auxiliary fastening bolt.
Choose too powerful engine not necessary. High revs will only harm your metal drills. Most craftsmen adapt to the grinding unit the engine seized from old washing machines.
After the assembly is completed, connect the tips, connect the engine and the entire electric car through the cable to the outlet.

Auxiliary devices

If you managed to collect a fairly useful grinding device for various drills for metal, wood or plastic, we advise you not to stop there.

There are several additional elements, equipping with a sharpening device, you will significantly expand its functionality and increase your own comfort when working on drills.

Check pattern. To determine right corners When sharpening drill, you will be useful for a special table or pattern. The template will always be at hand. With it, you determine how correctly sharpening angles are made, what is the duration of working edges, which angles between the jumpers and working edges. Templates are made of thin soft metal based on a new drill to its first use;
Guides. A kind of small consoles made from metal stripes. Their bolts are fixed on the housing of the sharpening device. When you work, you will need to put a drill on these guides, gradually submitting a sharpeble tool to the abrasive stone;
Communions. The easiest option is to take the usual metal transportation, cut off part of the device and secure on the stand. Sut off the part of the transport area where the scale is more than 30 degrees. This is due to the fact that the sharpening drills at a smaller angle is not carried out.

Multitasking device

If you make a similar device, accuracy and convenience of sharpening drills for metal will increase significantly. At the same time collect the design is quite simple. To make the mechanism, arma the following components:

Roller salads;
Guides;
Shaft;
Transporter;
Drill cartridge.

The guide is recommended to make a wide and consolidate the transportation on it.
A bolt will perform in the role of the swivel axis, which is inserted into a predetermined hole.
A guide and movable metal plate is located on the swivel.
On the surface of the plate is mounted axis and tube.
One end of the axis is used to install the drilling cartridge, and the other is applied under the handle.
The thrust plate will move due to the threaded axis.
At the bottom of the plate is the limiter. It performs two functions at the same time - fixes the mechanism in the desired position and indicates the desired angle.

The process of operation of the device looks like this:

The cutting drill is installed in the cartridge;
The plate is fixed in the desired position to create an angle of sharpening;
The device rotates along the longitudinal axis of the handle;
There is an angle;
The cutter turns 90 degrees, after which the second half of the metal drill is handled.

Operating Rules

Insofar as we are talking About working on a homemade sharpening device for drills, here should be sure to comply with some rules. They will protect you from injuries, and will also allow the drill to correctly.

When sharpening drills, make sure that the shoulders are the same. So you make sure that the drill is neatly, smoothly entered the device and after sharpening will be able to qualitatively drill holes.
Before starting the machine, make sure that the grinder is tightly fixed on the electric motor pulley.
The first step of sharpening the drill is performed by a large-grazing grinding disk. At the moment when burgers will begin on the metal drill, change the grinding disk to a more delicate to complete the sharpening.
Performing sharpening with your own hands, clearly stick to the specified angle.
The rotation of the sharpening circle should be carried out strictly towards the blade. In the opposite movement, you will not be able to work at a suitable way.
Make sure that the drill does not overheat when sharpening. Periodically stop, let's cool the drill to cool. But in no case do not compose by lowering cold waterBecause due to this, the metal will lose its strength.

Look visual video About assembly sharpening devices. Be sure to consider the diameter of the cutters that you have to be stuck on the machine so that the collective mechanism ensures high-quality and efficient product processing.

Fixture for sharpening drills with their own hands to make enough simple, the conditions for success will be knowledge of the rules for performing the sharpening of the cutting tool, as well as the ability to work hand tool and technical cutter.

Basic rules providing high quality sharpening are:

in one pass, it is necessary to remove a slight layer of metal;
in the process of performing operation, repeated cooling of the drill in aqueous or water-soda solution is performed;
the speed of rotation of the emery circle must be minimally possible;
drill, during sharpening, should not overheat;
in the process of performing work, the drill is sent against the movement of the abrasive circle.

The volume and nature of the work performed depends on the type of wear of the cutting tool. Worn can be qualified by:

rear surface;
jumpers;
corners;
facek;
front surface.

Depending on the type of sharpening drill, its technical characteristicsAs well as appointments, the following types of processing are recommended, somehow:

Type of sharpening	Diameter	Appointment and characteristics of sharpening angle
Single normal - "H"	up to 12.0 mm	For universal use. Corner-in accordance with the material being processed.
Single with a cumulative of the jumper - "NP"	up to 12.0 mm	To process steel casting. Corner- 115-120 °.
Single with a cumulative of jumpers and ribbons - "NPL"	Over 12.0 mm	For steel and steel casting, as well as cast iron. Corner- 115-120 °.
Double with a suction of the jumper - "DP"	Over 12.0 mm	For steel and cast iron with a slight crust. Sharpening is performed under two corners: 116-118 ° and 70-75 °.
Double with a cumulative of jumpers and ribbons - "DPL"	Over 12.0 mm	For universal use. Corner-in accordance with the material being processed.
By the method of Zhirov	Over 12.0 mm	Used in the processing of fragile materials. The main sharpening angle is 118 *, additional - 70 ° and 55 °.

Casting angles for spiral drills used in processing different materials It is necessary to specify before use, because They ran away from 85 to 135 *, due to their viscosity.

How to make a machine with your own hands

To sharpen spiral drills, any grinding machine (unit) operating from electrical network 380/220 Volt, equipped with an emery circle and equipped with a special device that ensures fixation of the rolled drill at a certain angle to the axis of rotation of the abrasive element of the device.

Basic requirements for special devices providing quality performance:

The axis of the adaptation must coincide with the axis of rotation of the abrasive circle. It can be with it in one horizontal plane or be slightly higher above.
Equipment and fixtures used must be securely secured.
The design of the device should provide the ability to sharpen the drill at various angles, depending on the user's need.

For the manufacture of one of the variants of such devices, you will need:

Handmade plumbing tool, a corner machine ("Bulgarian"), welding machine.
Sheet steel thickness 3.0 - 4.0 mm, as well as steel tube big diameterAvailable.

Machining work is performed in the following sequence:

The used grinding machine (№5 in the diagram) is firmly fixed on the selected surface.
A platform (No. 1 in the diagram) is manufactured from strip steel, on which the drill will be fixed (No. 3 in the Scheme).
The form of the site can be arbitrary, the only condition is at the location of the drill through the "Bulgarian" the groove is made.
The velocity (№6 in the diagram) operators are drilled on the site, which serve to fix the mounting plate (No. 2 in the diagram), as well as holes that ensure the connection of the adaptation to the grinding machine (not specified in the diagram).
The shape and size of the mounting plate can be arbitrary.
From the metal tube and strip steel, the attachment node is made to the base of the sharpening unit. The presence of a tube allows you to move the device to the vertical plane - the ability to change the sharpening angle of the drill appears.
The fixture attachment unit for sharpening to the housing of the sharpening machine depends on the type and device of the protection block of the emery circle (No. 4 in the diagram), as well as the presence of the stop (platform) of a particular emery unit.
If desired, the attachment node can be equipped additional elementsproviding an oscillatory movement of the device in a horizontal plane, which will ensure the required articulation in the process of performing work.
After all the elements of the fixtures are assembled, it is attached to the stop (casing) of the grinder and the performance of the manufactured fixture is checked.

For sharpening screw drills, various emery circles can be used, but in the light of the fact that consumables (The tool) is made of durable steel, then the abrasive elements must comply with this.

Basic Requirements for Emery Circles:

Mark Electrocorunda - 24a, 25a, 91a and 92a.
Granularity - 25-40.
Hardness - M3-cm2

Drill sharpening fixture can be performed in another other than the proposed version of the version - both more simple and complex design. The type of such a device is determined by its need and user skills make tooling with their own hands.

If you are constantly dealing with sharpening hard blanks, the surface of the drill will be unreasonable. It fills, it will be very hot and in the end will lose former strength. All this is a consequence of "release" of metal. That is why such a tool needs periodic sharpening with special devices.

How to make homemade fixtures for sharpening drills, which templates for this exist and what you need to prepare for work, you will learn from our article.

Features sharpening drills

Drills - these inexpensive devices, especially if we talk about those that are widely used for household needs. However, if you have the opportunity, then after blunting it is better to sharpen the tools than buying new ones.

There are factory devices designed for sharpening, but when you purchase them, you will spend greatly, and this does not fill out savings when you fail to acquire new tools. That is why there are a lot of masters collect machines for sharpening with your own hands.

It is worth noting that the bluntness concerns the metal drills, since the wood tools are practically not subject to this, except in cases of use at high speeds at a resinous billet. Also sharpening is not subject to Winged tips on stone or concrete.

But the metal drills are many accurate by all additional devices With their own hands, but the accuracy of such work is not always perfect, so it is desirable to use at least minimum mechanics.

How to make a fixture for sharpening drills with your own hands: learning video

To make such a device yourself, you will need a means of control (template). No matter how the drill is not sharpened, the accuracy is checked by a special template.

Simple black metal drills have an angle of edge from 115 to 120 degrees. If the metal is the other, then the angles of sharpening will also differ:

You can prepare immediately multiple templates Depending on the listed values \u200b\u200band, according to them, to perform sharpening with your own hands. The same drill can be applied to different types Billets, you only need to change the corners of the vertex of the workplace.

A simple but very convenient drainage device is sleeve different size which are attached to the base. You can make them yourself, relying on special drawings. Remember that the tool in the sleeve should not hang out, and the quality of drilling can worse, even if the error is only one degree.

You can make a large clip based on aluminum or copper tubes depending on the typical parameters drill or take a bar from soft material And it's a lot of holes in it. In the sharpener it is very important to put a comfortable girlfriend, thanks to which it will be possible to move the fixture for sharpening at the desired angle and keep the stop.

Listed fixtures for sharpening are manufactured by a lot of decades in a row and are still demanding. For assembling a sharpening machine You can take an oak bar instead of a corner.

The simplest machine for sharpening can be collected by simply installing a workbench or table opposite the side part. Even such a simple device provides high quality and accuracy of work.

Features of sharpening on a simple device

On the Internet you can find ready drawings Devices for sharpening drills, or to write them yourself, but for this it is necessary to understand the principle of working with a drill.

During work absolutely forbidden Move the drill move around your axis. If it is checked at least per millimeter, it will be spoiled, and you will have to re-process a short distance.

After the end of operation, the drill must cooletAlso perform measurements templates. The edges should be perfectly symmetrical up to tenths of a millimeter. This is especially important if the drill has a minimum diameter.

The sharpening may be accompanied by such errors:

How from the primary means do it yourself collect a grinding machine for spiral drills on metal?

For the basis of the device, you can take any grinding machine that is able to work properly, there is no axis beating, and it keeps turnover under load.

The task looks like this:

the girlfriend is obliged to strictly stand horizontally on one axis with the rotation of the emery;
the design should be safe, reliable and durable;
it should be provided with the ability to sharpen both manually and semi-automatic;
the shape of the girlfriend should contribute to the free omitting of the drill shank to the desired angle.

Specific parts for the manufacture of this device is not required, almost everything you need have homemade Masters. Billets are processed bulgarian, welding or sharp.

For the semi-automatic mode, the swinging stop is assumed, so you need to make a loop connection. Accurately pick up for lack of lights Bolt holes, bracket and tube.

The playground should move vertical axisSo that you can change the sharpening angle of drill. This axis can be fixed, and the girlfriend must swing, relying on the horizontal axis that when sharpening it provides the necessary articulation.

Support plate It is performed from a metal for 4 mm in thickness, and the main parts of the design must have a thickness of 3 mm, respectively. It provides its high strength. A girlfriend with emitted housing is connected rigidly. It is impossible to attach it to the protective casing, so you screw the bracket by metal "cheek".

To the support plate, then we screw the sequence plate itself for the drill with a thickness of 5 mm. In it for fixing the drill during processing is powered paz triangular form.

The design has an angle of rotation of 90 degrees, which allows to ensure attar different methods . Starting from the Leontheva method and ending with the clamp at a certain angle and the creation of an acute angle of the edge due to the crumis of the emery.

Drill during processing will not only firmly stand in the grooveIt will also be possible to feed it along the groove to the abrasive, and the angle of sharpening will not deviate. Thanks to partially exceeding the plane of the support plate above the axis of the disk movement, you can achieve necessary form Sharpening the head of the edge.

Before performing work, the drill should press the plate And put the cutting edge parallel to it. The alignment on this is over and can be brought to the sandpaper and tool. Sharpening need to be performed slowly and gently, carefully monitor the angle.

Thanks to this homemade tool achieved high sharpening accuracy And practically does not need a pattern. True, you will need time to install the machine and adjust the angle, then later you without difficulty quickly uatch the drills in the right amount.

But if you need to sharpen the boring, equipped with a carbide nozzle, then you can attach the swinging plate to the fixed angle. To do this, under the axial nut lay a few washers.

Application of emery circle in a homemade tool for sharpening

For universal grinding work, white circles based on electrocorund are mainly used. They are used for sharpening shovel, axes, knives and metal blanks.

In order to process carbide drills or high-speed metal, it is necessary to take abrasive green circles based on silicon carbide with marking 64c. But under household needs enough circle grainy by 25n.

Sharpening drills requires smaller fraction in the area from 8n to 16n. Remember that eathes on the basis of silicon carbide during operation are very hot, so the drill in contact with such an abrasive can not be kept. Let the metal cool after 2-3 approaches and cool it in soda water.

Edge quality depends on direction rotation abrasive. The working surface is obliged to run on the cut (go from top to bottom).

Peripheral the surface of Eataka When processing is obliged to be smooth. It can be edited by an ellubo-based nozzle. If the disk has a small diameter, the use of pliers in which the elbus cutter will be held.

So, we looked at how at home can be collected and use adaptations of different difficulties in order to sharpen drills and not only. Choose suitable option You can depend on your domestic needs.

The modern market is saturated with many species of various equipment designed to sharpen the drilling tool. When it does not need to have special skills and training. For example, such devices include industrial Riss 8100V devices having a high cost. In order to save money, you can make a tool for sharpening a drill on metal with your own hands.

Specificity of devices

IN household Electrocks and screwdrivers are often used to drill various wood, concrete, metal and ceramics. Many users of similar equipment have repeatedly encountered a problem that causes while running the working part of the drilling tool.

While working with the metal may occur intense heating cutting part of the drill, which exposes it to rapid wear and further unsuitability. In order to avoid this, it is necessary to periodically check the geometric norms of the cutting part and, if possible, be tolding it to the required parameters. For drilling metals, we usually apply a spiral roller. Additional tool checking before performing the work extends its life.

When working with wood, the cutting part is almost unable to wear, and the borants of concrete are equipped with solid winned plates, which do not need to need and are used to complete wear.

Sharpening Tools

How on industrial deviceAnd on the fixture for sharpening, the swell made with his own hands is recommended to apply a specialized template necessary to comply with the tool requirements. The use of the template makes it possible to set the necessary angle of the cutting part of the drill, which ensures high accuracy when working. During the holding drilling work It is necessary to individually select the sharpening angle of the tool, depending on the materials used.

When working with metals, you can use reference data providing information about the necessary standards when setting the sharpening angle. Sharpening angles parameters for rolling metal:

Steel, cast iron and solid bronze - 116-118;
Brass, soft bronze - from 120 to 130;
Copper - 125;
Aluminum - 140.

In the simple fixture for sharpening, the bore can be used in the inner diameter, which should coincide with cross section Drills and fixed on a rigid base under the required angle. The sleeve is selected by S. high accuracy - so that her inner diameter Coincided with a cross section of the stuffed tool. It is categorically impossible to allow weak fixation: it sharply reduces the quality of sharpening.

You can use a wooden bar in which holes must be drilled. different diameterWhat makes the device universal.

An important node is a girlfriend performing the following functions:

provides proper fixation of the object being processed and its movement relative to the sharpening circle;
it is an excellent focus during the execution of sharpening work.

Drawings of fixtures for sharpening swells can provide substantial help when assembling it. They can be found in various sources information. Studying the principle of operation of such structures, you can develop your own option that may differ from the basic individual features.

When working with sharpening devices, you must follow the following rules:

The processed tool during the work should be firmly fixed, which prevents it from turning around its axis;
At the end of the sharpening work, you must give a drill to cool, after which it will measure its corners using a template. The working surfaces of the cutting parts should not differ from each other.

Even with properly selected angles and the coincidence of their symmetry, a strong beating may appear, caused due to the difference of the length of the cutting edges, which is fraught with the breakdown of the drill. With the asymmetry of the cutting parts, slow down the drilling process and overheating of the cutting part of the tool. It makes a hole broken and enlarged in diameter.

Device for screwdriver

You can use traditional devices for sharpening: sharpened, electric drill or screwdriver, with additional improvements to them.

There is a ready-made industrial device for screwdriver and electric drillwhich is used as mini sharpened and allows sharpening at different angles.

To sharpen cutting part The tool on the homemade device, you must perform a number of conditions:

For sharding, emery circles apply swelling and drills. The most common in domestic conditions is a white circle of an electrocorundant, designed to drain the shovel, axes, knives, trim and other home inventory.

For carbide winners on concrete, abrasive circles of marking 64c are used. Compact disc grain is recommended to use brands 25N. When sharpening rapid, the disc brand from 8H to 16h is used. When working with emery from silicon carbide working surface Drills, heats up to high temperatures, so it is recommended to cool the metal with water with soda.

If you have to drill only wood, then you can not think about the sharpness of the drill, since the drill can regularly serve months and years without sharpening. But when it comes to the drilling of the metal, the drill sharpness becomes very important, in other words, you can only drill the metal drill. The difference is easy to feel, taking absolutely new drill. Starting quite quickly cut into the metal, with each minute the drill will be immersed in the metal, everything is slower, and it is still stronger to put pressure on it. The speed of blurring drill depends in particular from revolutions, feed speed, cooling and other factors, but no matter how try, the operation time of the drill to unsatisfactory performance is measured by moments. If the volume of work is significant, constantly buying new drills will turn out to be consistent, so it is better to learn them to sharpen them. Although it is still worth having several drills of one diameter (3-10, depending on the oh diameter and, accordingly, the price) to return to sharpening only when all the drills fumbled.

On the periphery drill the cutting speed of the maximum, and, therefore, the maximum heating of the cutting edges. At the same time, heat removal from the cutting edge corner is very difficult. Therefore, the blunt starts from the corner, then it extends to the entire cutting edge. Clearly visible her rounding. Then the back line is abrase. It appears strokes, risks coming from the cutting edge. As the risks wear are merged into a solid strip along the cutting edge, wider by the periphery and narrowing towards the center of the drill. The transverse cutting edge when wearing is crushed.

At the beginning of the blurring, the drill makes a sharp creaking sound. If the drill is not sharpened on time, the amount of heat released will increase and the process of wear will go faster.

To facilitate control of the geometry of the drill, the main thing that should be done is the template described below. With it, even if the sharpening is performed without fixtures, you can always check where it is still necessary to remove the metal, and, in the end, to get what it should happen (can not be that it does not work out, even if you have to run half the drill length) . To comply with symmetry, try to sharpen the time of each site and the pressure of the push were constant.

Sharpening spiral drills

The sharpening of the drill is made by its rear edges. It is very important that both feather (tooth) drill are sharpened completely equally. Perform it manually very difficult. It is also not easy to manually create the desired form of the rear face and the specified rear angle (where what angle see below).

For sharpening there are special machines or devices. If possible, it is better to sharpen drills on specialized equipment. But in the conditions of the domestic workshop, such an opportunity, as a rule, does not happen. Drills have to be hosted manually on an ordinary sharpe.

Depending on which form is attached to the back surface, there are different types Sharpening: single-layer, two-plane, conical, cylindrical, screw.

With single-layer sharpening the rear surface of the pen is performed as a plane. The rear angle should be 28-30 ° with such sharpening. With single-layer sharpening, the risk of painting the cutting edges is large. This method is the easiest performed when manual sharpeningrecommended for drills diameter up to 3 mm.

Universal drills with a diameter of more than 3 mm are usually subjected to conical sharpening. In order for the features of such sharpening, consider the conical sharpening scheme on the drill machine with an angle of 2 φ at 118 °. The figure below shows the grinding wheel and pressed to its end to the cutting edge and the rear surface of the drill.

Imagine a cone forming which is directed along the cutting edge and end grinding CircleAnd the vertex is the drill diameter by 1.9 of its values. The angle at the top is 26 °. The axis of the drill intersects with the axis of the imaginary cone at an angle of 45 °. If you rotate the drill, around the axis of the imaginary cone (as if to roll the cone from the end of the grinding circle), then a conical surface is formed on the rear face of the drill. If the axis of the drill and the axis of the imaginary cone are in the same plane, the rear angle will be zero. To formed the rear angle, it is necessary 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 diameter of the drill. The swing of drill along the axis of the imaginary cone with this mixture will provide the conical rear face and the rear angle 12-14 °. The greater the displacement value, the greater the rear corner. It should be reminded that the rear angle is changing along the cutting edge and increases to the center of the drill.

It is clear that it is very difficult to perform all these sharpening conditions. The drill, designed for sharpening, take the left hand for the work part, maybe closer to the intake cone, and the right to tail.

The cutting edge and rear surface of the drill is pressed to the end of the grinding circle and, ranging from the cutting edge, smooth movements right hand, without taking drills from stone, shake it, creating a cone surface on the back facet. Then repeat the same procedure for the second pen.

When sharpening, it is desirable as you can rather repeat the shape of the rear surface, which was after the factory sharpening, so as not to lose the required rear corners.

Another method of sharpening, widely used by domestic masters, is as follows. As in the previous case, the drill take the left hand for the work part is possible closer to the intake cone, and the right to tail. The cutting edge of the drill is pressed to the end of the grinding circle and the smooth movement of the right hand, without tearing the drill from the stone, turn it around its axis, draining the back surface. It is very important to maintain when rotating the drill the desired angle of its inclination to the end of the grinding circle. To do this, often use special sleeves when sharpening.

As a result of such sharpening on the rear surfaces of both feathers, a conical surface will be obtained, but the rear corner will not be formed. When driving the back surface about the wall of the opening and, therefore, the heating will be greater.

Due to friction about the grinding wheel, when sharpening the tool is heating. This causes a vacation to the tempered part of the instrument. Metal softened, loses hardness. Inappropriate sharpening leads the blade tool into disrepair. Therefore, sharpening should be carried out with multiple cooling of the drill in water or in water-soda solution. This requirement does not concern carbide drills. It is impossible to use for cooling oil. If for any circumstances the tool is sharpening dry, then:

for one pass, a slight layer of metal is removed;
the speed of rotation of the abrasive circle should be as low as possible;
the drill should never warm up to such an extent so that this is not tolerated.

Practice shows that the tool sharpening should be carried out against the movement of the grinding circle. Then the cutting edge is more durable, it is less likely to fminine and teasing.

For sharpening, grinding wheels from electrocorundu (grades 24a, 25a, 91a, 92a) with graininess of 25-40, the hardness of M3-cm2, on ceramic ligaments is used.

In production, it is usually imposed by imprisonment. The finishing makes the surface smooth, removes small jar. Drill, subjected to refinement, more resistant to wear than drill after sharpening. If you have the opportunity to execute the finish, use it.

For the finishing, grinding wheels from green silicon carbide 63C grain 5-6, the hardness of M3-cm1 on the bakelite bundle or circles from Elba Lo, the graininess of 6-8 on the Bakelite bond.

One of the main conditions proper sharpening Drills - preservation of its axisymmetry. Both cutting edges should be straightforward and have an identical length, the identical value of the corners at the top (and the angles of the pointing) in relation to the axis of the drill.

The correctness of the sharpening is verified by a special template.

a - pattern; b - checking the angle at the top and length of the cutting edges; in the alarm angle; G - angle between the jumper and the cutting edge.

It is made independently of the sheet of copper, aluminum or steel with a thickness of approximately 1 mm. The most durable pattern, of course, from steel. The template check the angle at the top, the length of the cutting edges, the angle between the jumper and the cutting edge. Instead of the rear angle, which is very difficult to measure, the pattern is measured by the alarm angle. The template is advisable to make before using the new drill to transfer the desired angles from the latter.

The uneven length of the cutting edges and the slope of them to the axis of the drill lead to the unequal load. The drill will be faster due to the intensive wear of the overloaded cutting edge.

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

The uneven load on the part of the drill will cause its beating in the cutting process and, as a result, an increase in the diameter of the obtained opening.

The easiest way to check the correctness of the sharpening is a trial drilling. If the feathers drill are sharpened unenochnakovo, then the less loaded will be less chips from the corresponding groove. Sometimes the chips appear only through one groove. The diameter of the opening can be exaggerated in comparison with the diameter of the drill.

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

1 - Rake; 2 - drill; 3 - emery circle; 4 - base; 5 - Holding.

The base is performed from a planed board with a thickness of 30-40 mm, to which at an angle of 30-32 ° (depends on the angle 2φ, see below, 30 ° for 2φ \u003d 120 °, 32 ° for 2φ \u003d 116 °) is sewn (nailed, glued ) wooden rail With a beveled at an angle of 25-30 ° (for single-layer sharpening) side face. This rail and focuses under the desired angle with a hidden with a stuffed drill with a grinding circle. Holding is made of rectangular wooden bar, one of the sidewalls of which is be built at an angle of 60-65 ° (depends on the angle of the side of the rail). This sidewall holder is pressed to the rake on the base board, which ensures the sharpening of the front angle of the drill in the required limits (25-30 °). On another sidewall, the holder is placed and drilled perpendicular to the plane of this sidewall through holes for each drill of a diameter. The length of the holder is chosen such that it is convenient to keep it when sharpening drills.

You will not install the fixture to the usual backrest (armrest), so you have to invent some table or shelf for it, you can transfer a sharpening machine to the table where there will be a place for this device. On the basis, put the holder with a drill to be sharpened close to the rail to be sharpened. Turn the drill in the socket so that the stuck edge is oriented horizontally. Left hand hold the drill at the stuffed edge, the right - drill shank. Climbing the power to the bevelled rail, move the drill to the emery circle and sharpen one edge. Then expand the drill and also process the second edge.

It can be done easier:

Sharpening angles and other drill characteristics

Spiral drill is a rod having two screw grooves to relieve chips. Thanks to the grooves on the drill, two screw feprenes are formed, or, as they are different, the tooth is called.

Spiral drill consists of working part, cervical, shank and paws.

A - with a conical shank; B - with a cylindrical shank; A -Ommer's cutting part; B - neck; B - the width of the pen; g - foot; d - leash; e - groove chip screw; f - feather; s - shank; and - jumper; L is a total length; L 0 - the length of the "working cutting part"; D - diameter; Ω - the angle of inclination of the "groove inlet screw"; 2φ - angle at the top; F - spiral ribbon width; ψ - the angle of tilt the jumper.

The working part is divided into the cutting and guide. All the cutting elements of the drill are located on the cutting part - the intake cone. The guide part serves to direct during cutting and is a spare with a drill in a blow. On the feathers of the guide part over the screw line are cylindrical chamfer tapes. The ribbon is used to direct the drill in the hole, as well as to reduce the friction of the drill on the wall wall. It should not be wide. Thus, the width of the drill ribbon with a diameter of 1.5 mm is 0.46 mm, a diameter of 50 mm is 3.35 mm. The shank drill and the foot serve to fix the drill in the spindle of the machine or cartridge. Drills can be performed with both neck and without it.

The diameter of the drill, measured by ribbons, unequal drill length. The intake cone is somewhat more than the shank. This reduces the friction of ribbons about the wall of the hole.

In order to understand the device cutting part of the drill, consider the basic principles of the operation of any cutting tool (including drills). One of the most important requirements to cutting tool It is that the separated chips freely separated from the place of cutting. The surface of the tool for which the chips runs is called the front face. This face is deflected back at some angle from the vertical plane.

1 - Wedge; 2 - processed object; γ (gamma) - an angle of front; α (alpha) - rear angle; Δ (delta) - cutting angle; β (beta) - angle of acunifications.

Thanks to this corner for the tool, cutting into metal and chips is freely coming on the front face. The angle between the front edge of the tool and the plane, carried out perpendicular to the cutting surface, is called the front angle and is indicated by the Greek bucken γ.

The surface of the tool facing the details is called the rear face. It is deflected on some corner from the surface of the workpiece to reduce the friction of the tool on the cutting surface. The angle between the rear face of the tool and the cutting surface is called the rear angle and denote the Greek letter α.

The angle between the front and rear face of the tool is called an angle of acuction and denote by the Greek letter β.

The angle between the front edge of the tool and the cutting surface is called the cutting angle and denote the Greek letter Δ. This angle is the sum of the alarm angle of β and the rear angle α.

Front and rear corner are the corners that need to be observed when sharpening.

And now we will find the faces described above and the corners on the drill, which is not at all similar to the instrument shown in the figure above. To do this, disseminate the cutting part of the drill with the plane of the AB, perpendicular to its cutting edge.

The cutting edge is the line of intersection of the front and rear edges of the tool. The front angle of γ in the drill forms a screw groove. The angle of inclination of the groove to the axis of the drill determines the magnitude of the front angle. The magnitude of the angles γ and α along the cutting edge of the variable, which will be described below.

The drill has two cutting edges, interconnected by a jumper located at an angle ψ to the cutting edges.

Having received a general idea of \u200b\u200bthe geometry of the cutting part of the drill, we will talk more about its elements. The front edge of the spiral drill is a complex screw surface. The face is the name conditional, since the word "face" suggests a plane. Screw groove, the surface of which forms the front line, intersecting with a fence cone, creates direct cutting edges.

The angle of inclination of the screw groove to the axis of the drill is indicated by the Greek letter Ω. The more this angle, the more front corner And the easier it is the yield of chips. But the drill with an increase in the tilt of the screw groove is weakened. Therefore, drill with a small diameter having less strength, this angle is done less than the drill of a large diameter. The angle of inclination of the screw groove also depends on the material of the drill. Drills from high-speed steel can operate in more intense conditions than carbon steel drills. Therefore, for them, the angle Ω may be greater.

The selection of the angle of inclination affect the properties of the material being processed. What it is softer, the angle of inclination may be more. But this rule is applicable in production. At home, where one drill is used for processing different materialsThe angle of inclination is usually associated with a drill diameter and varies from 19 to 28 ° for a drill with a diameter of 0.25 to 10 mm.

The shape of the groove should create sufficient space to place shavings and provide a lightweight removal from the groove, but it is not very weakening the drill. 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 core of the drill. The strength depends on the thickness of the core. If the groove is deeper, the chips will be better placed, but the drill will be weakened. Therefore, the thickness of the core is chosen depending on the diameter of the drill. In the drills of small diameter, the thickness of the core is a large proportion of the drill diameter than in the drills of a large diameter. So, for the drill with a diameter of 0.8-1 mm, the core width is 0.21-0.22 mm, and for the drill with a diameter of 10 mm core width of 1.5 mm. In order to increase the strength of the drill, the core thickness increases towards the shank.

The front edge of the drill does not drag.

The design of the screw grooves is such that, as the drill is approached from the edge to the center, their inclination angle decreases, which means that the front angle is reduced. The working conditions of the cutting edge at the center of the drill will be harder.

Rear corner, as well as the front, varies in size in different points cutting edge. At points located closer to the outer surface of the drill, it is less, at points located closer to the center, more. The rear angle is formed when the intake cone sharpening and on the periphery of the drill is approximately 8-12 °, and in the center of 20-25 °.

The jumper (transverse edge) is located in the center of the drill and connects both cutting edges. The angle of incitement of the jumper to the cutting edges can be from 40 to 60 °. In most drills ψ \u003d 55 °. The jumper is formed by the intersection of two rear edges. Its length depends on the thickness of the core of the drill. Since the thickness of the core increases towards the shank, the length of the jumper increases as a result of each sharpening. In the process of drilling, the transverse edge only interferes with the introduction of drill to metal. She does not cut, and the scraper or, or rather, presses the metal. No wonder she was once called scraping blade. With a decrease in the length of the jumper twice the feed force can be reduced by 25%. However, the decrease in the length of the jumper by reducing the thickness of the core will lead to a weakening of the drill.

A great influence on the operation of the drill is an angle at the top of 2φ. If the angle at the top is small, the chips to its lower edge will hurt over the wall of the hole and the conditions for the proper formation of chips.

Figure below shows the drill with normal angle Selection cone.

The edge of chips in this case is well fit into the groove. The change in the angle at the top changes the length of the cutting edge and, consequently, the load per unit of its length. With an increase in the angle at the top, the load per unit length of the cutting edge increases, while the resistance to the introduction of drill to the metal increases in the feed direction. With a decrease in the angle at the top, the force required to rotate the drill is increasing, as the conditions for the formation of chips deteriorate 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 less and the heat from the cutting edges is better.

Usually an angle at the vertex (2φ) of standard universal drills from carbon, chromium and high-speed steel is 116-118 ° and is considered suitable for many materials. But in order to provide best conditions Works, change it, as shown in the table.

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