Homemade stand design for sharpening drills. Device for sharpening drills with your own hands. Assembly of parts into a single apparatus and arrangement of safety elements
If we talk about those drills that are used by craftsmen at home, then their cost in stores is low. But even in this case, you should not use them as a consumable for a single use. After all, updating the drill to the best working condition will not be difficult if the master has the skill or special tools.
There are factory machines that are intended for sharpening, but this is a separate expense item, so most often craftsmen create such devices with their own hands.
Drills for metal create the most problems, and wooden blanks do not reduce the sharpness of the cutting edges so quickly.
To make a machine for restoring the sharpness of cutting elements, the necessary means of control (template), which is used to verify the tool.
Usually tools for ferrous metal, carbide bronze, steel or cast iron - with an edge angle of 115-125 degrees. The length of the other material, these parameters are different.
for soft bronze, red copper - 125, for brass alloys - 135;
for aluminum and soft aluminum alloys, granite, ceramics and wood - 135 degrees;
for magnesium and its alloys - 85 degrees;
for plastic, textolite and silumin - from 90 to 100 degrees.
Wizards, if necessary, make templates according to the above data. By the way, theoretically a single copy of the drill can be suitable for all these metals and other materials, if each time you sharpen different working surfaces.
An elementary handicraft fixture that is often used, bushings attached to the base. There are many drawings on the Internet for self-manufacturing. It should be noted that the tool must be well clamped, the accuracy depends on 1 degree.
If desired, you can make a significant size clip using aluminum or copper tubes correlative with the typical characteristics of drills or drill many holes in a soft metal workpiece. It is necessary that the sharpener has a comfortable hand rest to move the device and hold the stop.
This primitive sharpening machine is easy to install on a workbench or table.
Practical example of working with a drawing
The essence of the problem: there are drills, they need to be sharpened.
We will use one of the sharpening methods, close to the factory ones. Too lazy to catch hands. Better monkey way - put it and you're done. It took about 1 hour to make the fixture according to the finished drawing.
Some welding work on the template. A corner has been made. Put on the puck, it's just pressed on.
Let's try the first sharpenings, if everything is assembled correctly, we will refine and cultivate, make a quick adaptation.
After sharpening drills and we do a test. Two casting chips are visible, which means that the sharpening was carried out correctly.
The only drawback is that one chip is longer than the other, which means they missed the length of the edges. It is necessary to make an emphasis, which will regulate the length, ensure the symmetry of the edges. To do this, we will make a thrust washer, which will be exposed and machined. Or we cut it so that it becomes possible to process shorter drills. 
When working with hard workpieces, the working surface of the drill wears out quickly. A dull drill gets very hot and loses its strength. This is due to the "release" of the metal. The tool needs to be sharpened periodically. However, this does not only apply to drills.
Drills are inexpensive devices. In any case, those models that are used in the household. However, buying a new tip every time it becomes dull is wasteful.
There are factory-made sharpeners, but this violates the concept of economical use of home tools.
Wood drills practically do not become dull, except that the tool can be “driven” at high speeds in a resinous workpiece. Pobedite tips for concrete and stone are not sharpened. It remains to sharpen the drill for metal. Many experienced locksmiths carry out this procedure with their own hands, without any tools.
However, the accuracy of the work leaves much to be desired, and not every home master's eye is developed so professionally. In any case, minimal mechanization is necessary.
IMPORTANT! Sharpening tips with a file, needle file and even sandpaper is pointless. To do this, you need an electric emery (grindstone).
How to make a homemade tool for sharpening drills?
First of all, it is necessary to acquire a means of control. No matter how you sharpen the drill, you need a template to check the accuracy of the work.
Conventional drills for working with ferrous metals have an edge angle of 115-120 degrees. If you have to work with different materials- read the table of angles:
Workpiece material sharpening angle Steel, cast iron, carbide bronze 115-120 Brass alloys, soft bronze 125-135 Red copper 125 Aluminum and soft alloys based on it 135 Ceramics, granite 135 Wood of any species 135 Magnesium and alloys based on it 85 Silumin 90- 100 Plastic, textolite 90-100
Knowing these values, you can prepare several templates, and in accordance with them, sharpen yourself. In this case, you can use the same drill for different workpieces, you just need to change the angle of the top of the working area.
The simplest, but very effective tool for sharpening - bushings of different diameters, fixed on some kind of base.
Schematic drawing of the device in the illustration:
IMPORTANT! The tool in the sleeve should not hang out, an error of only one degree will reduce the quality of drilling.
It is best to make a whole clip of copper or aluminum tubes, for standard drill sizes. Or drill a sufficient number of holes in a bar of soft material. The main thing is to install a convenient handrest on your grinder, which will allow you to move the sharpening device at the right angle, and serve as a reliable stop.
Our grandfathers used this method. Only as a material for the manufacture of a grinding machine - a corner, an oak bar was used.
In principle, it was enough to place a table or workbench opposite the side surface of the emery - and the grinding machine is ready. At the same time, the quality and accuracy of processing was at a high level.
There are different drawings of sharpening devices.
You can use ready-made, or develop it yourself. The main thing is to understand the principle of working with a drill.
IMPORTANT! When working on a grinder, do not allow the drill to rotate around its axis.
If the tool turns at least a millimeter, it will be damaged, and you will have to grind a certain distance for re-processing.
After finishing sharpening, let the drill cool down and take measurements using a template. Both edges must be symmetrical to the nearest tenth of a millimeter. This is especially important for small diameter drills.
The diagram shows typical mistakes self-sharpening:
The design of a grinding machine for twist drills for metal, made from improvised materials
As a basis, a household grinding machine with a proud inscription "made in Germany" is taken, which has all the signs of a product from the Middle Kingdom. Nevertheless, it works properly, there is no axle beating, it keeps the speed under load.
The terms of reference are as follows:
- the handpiece must be strictly on the same horizontal line (or above it) with the axis of rotation of the emery;
- the design is strong and reliable, ensuring the safety of work;
- there should be the possibility of both manual sharpening and semi-automatic - using a tool;
- the shape of the handpiece allows you to freely lower the drill shank to the required angle.
No scarce parts are required for the manufacture of the device. All the materials were actually lying underfoot in the barn. The processing of blanks was carried out by a grinder, the same upgraded sharpener, and welding.
Since the emphasis was supposed to be swinging (for semi-automatic mode), a loop connection was made. The holes of the tube, bracket and bolt are matched exactly to avoid backlash. The resulting device has two degrees of freedom.
The platform can be rotated along the vertical axis - changing the angle of sharpening the drill. This axle is fixed. Also, the handpiece can swing, leaning on a horizontal axis, providing the correct articulation during sharpening. This degree of freedom is not fixed.
For the base plate, metal 4 mm thick was chosen, the remaining structural elements - 3 mm. The strength is more than sufficient. The handpiece is rigidly connected to the body of the emery. Of course, attach it to protective cover is unacceptable, so we fasten the bracket with the help of an additional metal "cheek".
The actual guide plate for drills is screwed to the handpiece (more precisely, to the base plate). The plate is 5 mm thick, it has a triangular groove for fixing the drill during processing.
The angle of rotation of the structure is 90 degrees. This will ensure sharpening in any way, from the Leontiev method to pressing at one angle with the development of an acute edge angle due to the curvature of the emery.
The drill being machined is not only firmly held in the groove - it can be freely fed to the abrasive along the groove, without the slightest deviation of the sharpening angle.
Due to some excess of the plane of the base plate above the axis of rotation of the disk, the optimal shape of the sharpening of the back of the head of the working edge has been achieved.
Before starting work, we press the drill against the plate and set the cutting edge parallel to the plate. This completes the adjustment and you can feed the tool to the emery. Sharpening a drill requires certain skills, do everything slowly, carefully monitor the sharpening angle.
The accuracy of the work is the highest, the template is actually not required. It takes some time to install the fixture and adjust the angle, but you can quickly sharpen a couple of dozen drills without spending any effort.
If it is necessary to sharpen a drill with a carbide tip, the oscillating plate can be fixed at a fixed angle. To do this, you just need to put a couple of washers under the axle nut.
A few words about the emery wheel
Usually, for universal tasks, a white circle of electrocorundum is used in a home grinder. It sharpens knives, axes and shovels very well. With it, you can quickly process metal workpieces.
When sharpening carbide drills (and high-speed metal also requires a harder disk), a green silicon carbide abrasive wheel is used. Such circles are marked 64C.
Grit for household work is usually selected 25H.
When sharpening drills, a smaller fraction is required, it is better to work in the range 8H - 16H. It must be remembered that silicon carbide emery gets very hot during operation. Therefore, you can not keep the drill in contact with the abrasive for a long time. After 2-3 approaches, let the metal cool. Best of all, cool it with baking soda water.
IMPORTANT! The direction of rotation of the abrasive determines the quality of the edge. The working surface of the disk should run into the cut, that is, move from top to bottom.
The peripheral surface of the emery, as the main processing surface, must be perfectly flat. You can edit it with an elbor nozzle. For discs of small diameter, it is quite possible to get by with pliers in which the CBN cutter is held.
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.
It is necessary to know that universal value no. 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 tool on e / 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:
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. And here home master have to look for an alternative to high-quality factory fixtures in more simple solutions that can be used in a conventional 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 get different types 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 subpoint described above is used here, which also allows you to increase the life of the drill when machining. 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 principles.
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.
How to make a tool for sharpening drills. Device for manual sharpening of twist drills. Some time ago, I accidentally stumbled (meaning the author of the article, see the source) on the net to very useful video tutorials by V. Leontiev on manual sharpening of twist drills:
But then an idea arose how to make sharpening drills even easier and more convenient. As a result of reflections and experiments, the device described below appeared. First, it was necessary to modernize - to bring to mind the existing factory-Chinese (like German) grindstone. Because it was almost impossible to work with him using the techniques of V. Leontiev.
Electric grinder of factory-Chinese production.
Flimsy standard handbrake bracket.
Unsuitable for work design of the handbrake.
Firstly, the bracket for attaching the handbrake to the disc casing is too flimsy, made of metal 2 mm thick. It bends with little effort. Therefore, naturally, the sharpening angles are +/- kilometer! And the shape of the handpiece absolutely does not allow you to make a normal back angle according to the V. Leontiev method, since the drill rests against the angle of the bracket when lowering the shank. Moreover, the handbrake itself is installed BELOW the axis of the disk. That is, there is no way to get a normal rear angle at all, unless you use the end surface of the disk.
The plane of the platform of the handbrake is much lower than the axis of rotation of the disk.
New handbrake bracket.
For a normal bracket, a piece of metal with a thickness of 4 mm, a larger size, and additional mounting screws were used. The old bracket was fastened with two rivets that had to be cut off. Now the new bracket is much stiffer than before. Also, from pieces of a corner and a strip, a horizontal shelf of a handrest with additional mounting holes was welded. Its position can be adjusted within certain limits.
Comparison of the thickness of the metal in the new and old handpieces.
The new bracket is attached at 5 points.
Fixture details. Bracket. Handyman. Swivel plate...
Next, the device itself was made directly. It consists of a turntable with a welded bushing that can swing on an axle fixed in an eyelet, which in turn is attached to the hand rest. From above, a guide plate for drills is attached to the rotary plate, in which a triangular groove is selected.
Assembly device. Plate in a horizontal position.
Assembly device.
Sharpening device.
First, instead of this plate, a guide in the form of a piece of a corner was tested (as in the video by V. Leontiev), but this option is not at all suitable - it is difficult to fix the drill normally (it tries to run to the right when it touches the disk), especially since it also requires feed forward when forming a back corner. In general, the corner (it is in the photo) is completely unsuitable.
Device in the down position.
Working with the device resembles the movements of the author of video tutorials, only instead of a finger and an eye, the swing axis and the set angle of sharpening the drill are used. It is much more convenient with the device to control the parallelism of the machined cutting edge of the drill to the disk. You just need to turn the insert down and press the drill into the groove so that the line of the cutting edge is parallel to the plane of the insert - the axis of oscillation of the insert. This moment is shown in the photo.
Installing the drill on the handpiece to the grindstone.
First, the edge itself is formed. When processing the back corner, it is necessary to simultaneously lower the plate down and feed the drill itself forward to the disk. It is necessary to try to prevent the drill from rotating around its axis when forming an edge and processing a back corner. I control the symmetry of the edges in the same way as in the video tutorials. By the way, instead of a swinging plate, you can install a piece of a corner with fixed angles- sharpening and back - this is for sharpening carbide drills. It is only necessary to determine in place the required length of the sides of the corner to obtain the desired rear sharpening angle, since it also depends on the diameter of the disk and the location of the handpiece relative to the axis of rotation of the disk.
Installing the drill in the guide slot of the plate.
Drill setting control. The cutting edge of the drill is parallel to the plate surface.
Guide slot configuration.
Device for manual sharpening of twist drills.
