I confess that sharpening a tool has always caused me a quiet horror. You need to think not only about a rotating grindstone, which is a source of potential danger, but also to keep the sharpening angle ... I think the article will be useful for beginner brainers, and for experienced comrades, I have a strong request to supplement the information below or tell about my method of maintaining the sharpening angle .

materials

• Wooden block;
• Screw.

Instruments

• Protractor;
• Malka (device) is a carpentry and metalwork tool for marking and measuring angles, drawing parallel lines. It consists of two parts fastened together with a clamping screw. The thicker part (block - base) is pressed against the workpiece, the thin part (ruler) is marked. Sometimes a scale for measuring angles is applied between the two parts of the bevel. Large malki can be used in construction work;
• Drill with a drill for wood;
• Screwdriver.

Step 1: 59 degrees

Draw two straight lines on paper at an angle of 59 degrees. The goal is to sharpen the drill at this angle.

Step 2: Mark the corner on the bar

Using a bevel, we transfer the angle of 59 degrees to a wooden block. I used hardwood as a blank. The thickness of the bar is 15 mm. The guide will be a screw with a fine thread for a slotted screwdriver, so the through hole must be slightly smaller in diameter than the diameter of the screw so that it is tightly screwed into the bar. Drilling into wood is easier when you start drilling at an angle. By eye, we determine the place where it is most convenient to place the screw.

Step 3: Screw in the screw and check the angle

We screw the screw into the bar. In advance, you should determine the maximum diameter of the drill that will be sharpened. For this crafts the drill diameter will be more than 15 mm. Therefore, you should choose a screw of sufficient length so that it passes through the block and protrudes to half the largest diameter of the drill being sharpened.

If the angle at which the screw exits the block does not match the reference line, drill another hole and try again.

Step 4: Using a Reference

Turn the screw a few turns so that the end of the thread is above the center of the drill.

Once you've sharpened one side (using the threads of the screw as marks), turn the bit half way and look at the marks on the screw. Repeat the operation for the other side of the drill.

Step 5: Sharpening

As for sharpening drills, the site provides a detailed article. In addition to the material presented in it, I suggest watching a video of an English-speaking kulibin.

Thanks for attention)

The technological process of mechanical processing of materials includes a wide variety of operations, which require high-quality and sharp tools. So, in a mechanical workshop at any machine-building enterprise, a set of turning, milling, drilling and more complex machines can be used. They use their own type of tool, for each of which there is a specific method of sharpening.

Features of the drills

Machining of metal is associated with huge loads on the tool. In general, it consists of three main parts: connecting, body and cutting. So the cutting part is a small wedge-shaped element designed to penetrate the metal and remove part of it from the workpiece.

If, for example, everything is clear in a turning tool or a disk cutter with the shape and design of the cutting part, then when processing holes on a drilling machine, everything is much more interesting and complicated, so you need to know how to sharpen the drill correctly. This is a tool designed for axial metal processing. That is, the feed movement is directed strictly along the axis. This should be considered before sharpening the drill for metal, because the wrong cutting angle will lead to vibration and breakage.

The main elements of the cutting part of the drill

Before sharpening a drill for metal, you should familiarize yourself with the design of its cutting part, which includes the following elements:

1. Main cutting edge.

2. Auxiliary helical cutting edge (ribbon).

3. Jumper.

4. Front surface.

5. Back surface.

What is needed for sharpening?

At the enterprise, everything necessary for the restoration of the instrument is always at hand. But the home master has to look for an alternative to high-quality factory fixtures in simpler solutions that can be used in an ordinary garage. And yet, before sharpening a drill for metal, stock up on a minimum set:

1. Grinding wheel. It must be mounted on a rotating shaft. The device is popularly known as "emery". Very common in the garage.

2. Capacity for coolant.

3. Coolant (water or machine oil).

In order to withstand the angle of sharpening the drill, such a set may not be enough. After all, you will have to control the process "by eye", which is unlikely to work out without some experience. In this case, the basic kit also needs to include a tool for sharpening the drill, which you can buy or make yourself.

Controlled parameters

When everything is ready, it is necessary to familiarize yourself with some theory in order to have an idea about the main parameters of an axial cutting tool. Before you sharpen the drill correctly, you need to know its angles:

1. Front. Defined in the main cutting plane (running perpendicular to the main cutting edge) as the angle between the rake face and the main plane (perpendicular to the cutting speed vector). It is directed tangentially to the circle of the drill.

2. Rear. Also defined in the principal shear plane as the angle between the flank and the cutting plane (passes through the velocity vector and the cutting edge).

3. Corner at the top located between the two main cutting edges when viewed from the side of the drill.

The optimal value of the front angle is 18-20 degrees, the rear one is 10-12. The corner at the top in drills for metal has a standard value of 118 degrees.

Sharpening process

Now let's talk about how to sharpen a metal drill on ordinary sandpaper. The main sharpening of this axial tool is carried out on the rear surface. To do this, turn on the emery, firmly take the drill in your hand so that the main cutting edge is directed towards the rotation of the grindstone. Now we bring the edge to the grindstone, after which we turn the drill by the shank so that the cutting edge is parallel to the surface of the circle. We do the same operation with the second cutting edge. The result is the so-called simple sharpening of the drill, which is optimal for most metal processing modes.

Simple sharpening is used for drills with a diameter of up to 10 mm. By increasing this parameter, you can additionally perform a subpoint of the front surface. As a result, the rake angle decreases, which means that the thickness of the blade (the so-called cutting edge angle) and, accordingly, the drill life increases.

Sharpening with a fixture or machine

The method described above can be called artisanal, since it is simply impossible to achieve precise control of the drill parameters directly during sharpening. In the best case, you will check the angles after sharpening is completed, and in the worst case, you will simply check how much better the drill has become. And how to sharpen a drill?

Of course, for this it is better to use more advanced options that will allow you to tune in to certain angles in advance. In this case, you will need a device or machine for sharpening drills.

If the scale of work in your workshop is large enough, and regrinding of the tool is required constantly, then purchasing a machine will be optimal. It will greatly simplify the process, especially if you need to regrind carbide drills for metal. The main advantage of its use is the exact observance of predetermined parameters. With a large amount of work, it is unacceptable to use an incorrectly sharpened tool, as this will lead to a decrease in productivity. Modern grinding machines allow you to obtain various types of drill sharpening:

1. X-type. Mainly used for drilling in blind holes. Designed to reduce axial cutting force.

2. XR type. Used for universal drills. Cutting into the material is somewhat worse than in the first type, however, such drills have increased strength and durability.

3. S-type. The sharpening described above is used here, which also allows you to increase the life of the drill in the processing of various materials (from cast iron to stainless steel).

4. N-type. A subpoint is also used, but of a smaller size. Drills with this sharpening are used for deep drilling.

Fixture design

As it has already become clear, manual sharpening of a drill is the business of a professional who not only knows the correct angles, but also feels the cutting process. Unfortunately, such a flair comes only after many years of practice with a drilling machine or drill. You should not experiment, as you can make your own or purchase a sharpening device. In both cases, it will include the same structural elements and work on the same principle.

So, the main task of the fixture is the correct orientation of the drill relative to the plane of the grinding wheel. To do this, its design includes a base plate, on which it is desirable to place both the device itself and the electric motor, on the shaft of which the grindstone is located. There is also a rotary column on the plate, on which the drill is fixed. It must be able not only to rotate, but also to move towards the grinding wheel.

As a column, you can use any bearing assembly with a shaft, for example, from an old drill. A drill bed is fitted on the shaft rings (you can use an adapter sleeve), to which it is pressed with screws. After fixing the drill, the sharpener drive is turned on, the column is brought to the grinding surface and rotated to give the back surface of the drill the correct shape. It is important that during the initial setting of the fixture, the angle at the top of the drill is 118 degrees.

Sharpening nozzles

Another simple and convenient way involves the use of a device such as a nozzle for sharpening drills. Its main advantage lies in its versatility and ease of use. The device has a cylindrical shape. On the one hand, there is a connecting node, through which the nozzle is installed on the drill spindle. On the other side there are holes for installing drills of a certain diameter. For sharpening, the drill is inserted into the hole, after which the sharpening mechanism is driven by the drill motor.

Security measures

The sharpening of the drill is associated with the formation of small particles that break away from the sharpener during wear. They heat up and scatter in different directions in the form of fiery sparks, so for safety, you should use goggles and gloves.

When sharpening a drill without a tool, make sure to securely fix its position. Otherwise, upon contact with the sharpener, it can simply be pulled out of your hands.

If you are constantly dealing with sharpening hard workpieces, then the surface of the drill will become unusable very quickly. It will become dull, get very hot and eventually lose its former strength. All this is a consequence of the "letting go" of the metal. That is why such a tool needs periodic sharpening using special devices.

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

Features of sharpening drills

Drills are inexpensive devices, especially if we talk about those that are widely used for domestic needs. However, if possible, then after blunting it is better to sharpen the tools than to buy new ones.

There are factory-made sharpening devices, but you will spend a lot on buying them, and this will not make up for the savings if you refuse to purchase new tools. That is why many masters collect machine tools for sharpening by hand.

It is worth noting that blunting applies to metal drills, since wood tools are practically not affected, except when used at high speeds with a resinous workpiece. Also not subject to sharpening Pobedite tips for stone or concrete.

But many drills for metal are sharpened using all the additional devices with their own hands, but the accuracy of such work is far from always ideal, so it is advisable to use at least a minimum of mechanics.

How to make a do-it-yourself drill sharpener: a tutorial video

To make such a device yourself, you will need a control tool (template). No matter how the drill is sharpened, the accuracy is checked by a special template.

Simple drills for ferrous metal have an edge angle of 115 to 120 degrees. If the metal is different, then the sharpening angles will also be different:

You can prepare right away multiple templates depending on the listed values ​​​​and, in accordance with them, do sharpening with your own hands. The same drill can be used for different types of workpieces, you just need to change the angles of the top of the workplace.

A simple but very convenient dragging device is bushings of various sizes that are attached to the base. You can make them yourself, based on special drawings. Remember that the tool in the sleeve should not dangle, and the quality of drilling may deteriorate 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 of the drills, or you can take a bar of soft material and make many holes in it. In the grinder, it is very important to put a convenient handrest, thanks to which it will be possible to move the sharpening device at the right angle and hold the stop.

The listed sharpening devices have been manufactured for many decades in a row and are still in demand. For sharpening machine assembly with your own hands, you can take an oak bar instead of a corner.

The simplest sharpening machine can be assembled by simply placing a workbench or table opposite the side of the emery. 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 finished drawings devices for sharpening drills, or sketch them yourself, but for this you should understand the principle of working with a drill.

During work Absolutely forbidden allow the drill to move around its axis. If it turns at least a millimeter, it will be damaged, and you will have to grind a small distance for re-processing.

After finishing work, the drill should cool down, also measure with templates. The edges must be perfectly symmetrical down to tenths of a millimeter. This is especially important if the drill has a minimum diameter.

Sharpening may be accompanied by such errors:

As from improvised means with your own hands assemble a grinder for twist drills for metal?

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

The task looks like this:

• the handist must strictly stand horizontally on the same axis with the rotation of the emery;
• the design must be safe, reliable and durable;
• it should be possible to sharpen both manually and semiautomatically;
• the shape of the handpiece should facilitate the free lowering of the drill shank to the desired angle.

Specific details for the manufacture of this device are not required, almost every home master has everything you need. Workpieces are processed grinder, welding or grindstone.

For the semi-automatic mode, a rocking stop is assumed, so you need to make a loop connection. Pick the right one for lack of backlash bolt, bracket and tube holes.

The platform must move vertical axis so that you can change the angle of sharpening the drill. This axis can be fixed, and the hand rest should swing, while leaning on the horizontal axis, which provides the desired articulation when sharpening.

Base plate made of metal 4 mm thick, and the main parts of the structure must have a thickness of 3 mm, respectively. This ensures its high strength. The handpiece with the body of the emery is rigidly connected. It is impossible to fasten it to the protective casing, therefore, use the metal "cheek" to screw the bracket.

Then we fasten the guide plate for drills with a thickness of 5 mm to the base plate. In it, to fix the drill during processing, it is sawn triangular groove.

The design has an angle of rotation of 90 degrees, which allows you to provide z sharpening by different methods. Starting from the Leontiev method and ending with pressing at a certain angle and creating an acute edge angle due to the curvature of the emery.

The drill during processing will not only stand firmly in the groove, it can also be fed along the groove to the abrasive, and the sharpening angle will not deviate. Due to the partial excess of the plane of the base plate above the axis of movement of the disk, it is possible to achieve the desired shape of sharpening the back of the edge.

Before performing work, the drill should press on the plate and set the cutting edge parallel to it. The adjustment is over and you can bring the tool to the emery. Sharpening must be done slowly and carefully, carefully monitor the angle.

Thanks to this homemade tool, high sharpening precision and almost no template is needed. True, it will take time to install the machine and adjust the angle, but then you sharpen drill bits quickly in the right amount.

But if you need to sharpen a drill equipped with a carbide nozzle, then you can attach a swinging plate to a fixed angle. To do this, put several washers under the axle nut.

Using an emery wheel in a homemade sharpening tool

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

In order to process carbide drills or high-speed metals, it is necessary to take abrasive green wheels based on silicon carbide marked 64C. But for domestic needs, the grain size of the circle is enough for 25N.

Sharpening drills requires a finer fraction in the area from 8N ​​to 16N. Remember that silicon carbide emery gets very hot during operation, so the drill cannot be kept in contact with such an abrasive for a long time. Let the metal cool down after 2-3 passes and chill it in soda water.

Edge quality depends on direction abrasive rotation. Its working surface must run into the cut (go from top to bottom).

Peripheral emery surface during processing must be even. It can be edited with a nozzle based on CBN. If the disc has a small diameter, it is allowed to use pliers, in which the elbor cutter will be held.

So, we looked at how at home you can assemble and use devices of varying complexity in order to sharpen drills and more. You can choose the appropriate option depending on your household needs.

Drills are different, but in practice we often use those that are designed to work with metals. Despite the fact that such a tool is made of special grades of steel and subjected to special hardening, it becomes dull over time. A prudent owner will never throw away even the cheapest twist drill, since it is easy to restore its performance on its own, especially since such a person always has an “el / emery” (the simplest grinder) in a private house or garage. How to sharpen a drill for metal correctly will be discussed in this article.

Sharpening is different, and it largely depends on both the diameter of the drill and the specifics of its application. For example, on the type of metal with which it is supposed to work (“hard” or “soft”).

What to look out for

• In the process of work, the edge is located strictly parallel to the working surface of the stone (grindstone axis).
• The main thing is the gradual sharpening. It is undesirable to “press” the drill to the circle too much.
• All edges must be the same length.
• An indicator of the completion of the work is the absence of reflective glare on the surface to be treated.

You need to know that there is no universal value. For each type of material being processed, its own sharpening angle is selected. Approximate values ​​are shown in the table.

Types of sharpening

single plane

It is used, as a rule, for drills no more than 3 mm. The disadvantage is that in the process of work, partial "chipping" of the edge may occur, so this technique requires special care. The point is that the tool is applied to the circle and moves parallel to its working surface.

conical

Suitable for drills over 3mm. The tool is held with two hands, while the feathers are sharpened sequentially (light pressure on the stone with a slight “wiggle”).

fine-tuning

It is desirable to do it after the drill is sharpened. The task is to remove the smallest notches, grind the cutting edges. For this, an appropriate stone (“soft”) is used.

For many people, self-sharpening a tool on electric / emery is fraught with certain difficulties or becomes impossible. The reason is poor eyesight.

Judging by the messages on various forums, neither good lighting nor glasses with large diopters help. Those for whom this is really a problem can be advised to purchase a special machine. For example, made in China. It is inexpensive - about 1,500 rubles.

And despite the fact that we have a “cautious” attitude towards products from this country, to put it mildly, those who have already worked with them speak very well of such products (for example, Caliber-ezs 200s). The range of machines is quite large, so there is always a choice (Micra-10 and a number of others).

To ensure greater accuracy of sharpening and facilitate this process, a special device can be made. Its meaning is clear from the figure.

If there is no e / emery at hand (and strict requirements for the angle), then you can use a “grinder” to sharpen the drill.

A video from the respected master Viktor Leontiev clearly demonstrates the whole process, so if some of the nuances of sharpening remain incomprehensible, you should watch it:

Accurate and centered drills are required for well-functioning work. We suggest considering where you can buy a machine for sharpening drills, how a home-made unit is made, and also how household models differ from industrial ones and what is their price.

Types of drills and basic concepts

There are several types of drills, because. they are divided according to the principle of operation and the ratio of working surfaces, they also need to be sharpened in different ways, let's get acquainted with the main ones:

• spiral. They are used in almost all types of industry, domestic work, repairs, etc.;
• flat - these are 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.

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, in particular this process manifests itself in the front surface. It is a large accumulation of chips that plays a major role in the deformation of the plastic parts of the drill: during operation, it heats up, and under the influence of 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 tough - copper and steel.

Photo - Cleaning the drill from chips

Drilling 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, respectively, the cutting edge becomes somewhat dull and changes its center. All corners of the work surface must be above the end face, this is the only way to ensure a normal and standard relief angle.

The easiest and most effective way to sharpen a drill at home is to use an electric sharpener. You can work with a conventional whetstone 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. The universal manual grinder has a motor, the speed of which is 1500-2000 min -1 . Optimum power: up to 300 watts. Such models are available from Doctor (Doctor), Vollmer, Sturm, Proxxon, Drill and Weinig.

Photo - Sharpened drills

Orientation is carried out along the cutting edges, it is necessary to act strictly in the direction of the spiral grooves, because they do not change their shape even when exposed to a large amount of chips. We fix the drill so that the edge to be sharpened is strictly parallel to the axis of the grinding tool. The most important question: when is the working part sharpened? As soon as you see a reflection of light from the work surface, this means that 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 center the drill earlier, in which case you will lose its balance, and during operation the tool will deviate by several degrees from the standard-set parameters. The angle between the lumps is the most important sharpening parameter.

Photo - Cutting angle

Standard sizes have the following form:

Steel alloyed, structural, tool - 90 more 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 the standard and deformed parameters. To control the sharpening process, you can order a special drill template with the desired diameter and angle. The photo shows a drill processing scheme with such a device.

Photo - Sharpening template

If there is no money or time to purchase a template, use the "old-fashioned" method: we act according to the rule of left-hand mechanics. We bend the arm, and replace it in this way over the drill so that the cutting surface is closed from several sides, a kind of corridor should be obtained. 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 viewed with one eye).

Photo - Left hand rule
Photo - Glare check

Using a homemade electric machine, it is very important to control the process of sharpening drills. For a complete violation of accuracy, it is enough to make a mistake of 1 mm. Small diameter core drill auto sharpener can also be used for discs, knives, scissors, chains, etc.

Video: Sharpening machine Energomash TS 6010C

professional ways

The methods listed above are suitable for narrow-profile home use, but if you need to grind drills in series, then you will not have enough time or energy to manually center, check or sharpen. Consider how a professional drill machine is used.

The grinding wheel must be made of fine abrasive material. The sharpening point should be illuminated at the right angle with respect to the drill. The employee must wear safety goggles 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 the possibilities. One mechanics forum even advised to always carry a drill with you so that you can check the effectiveness on the spot.

Price overview

Buying an inexpensive drill sharpening machine in Ukraine, Russia or Belarus is real, the main thing is to choose the right model (for metal, wood or plastic), caliber (dd750хibm, drillgrind, edbs2001 - universal), and power. We offer to consider the average prices for such devices:

Now desktop and universal machines of such brands as DrillGrind, Shturm (produced by Energomash), BSG, BSM, ESM, MICRA, V391, Diold, EZS, NKCh are very popular. They can be found in a professional store, on the Internet, on the forums under the heading “Sell electrical appliances”. The main thing is to make sure that the documentation corresponds to the data declared by the seller.