How To Sharpen Drills For Metal With A Grinder
We sharpen a drill for metal with our own hands; instructions and a detailed description of the process of sharpening drills for metal, nuances and tips,
We sharpen a drill for metal with our own hands instruction
Drills are known to dull over time. Many just throw them away and buy new ones. However, with a truly masterful approach to any business, you can give a second life to a dull drill. Over, it is possible to correctly sharpen a drill for metal at home, without the use of any high technologies.
At home, for household needs, drills of small diameters are mainly used, as a rule, no more than 16 mm. This is about sharpening such small drills and there will be a conversation. The best way to cut a drill is on a grinding wheel. Every self-respecting owner has a winepress in his garage. If not, then the second option is to fix the electric drill, grinder (which is available). For us, one needs to get a rotating whetstone (disc).
Water, machine oil can be used as a coolant. If the drill is not periodically immersed in coolant, it will overheat and will not be able to withstand the required load and temperature conditions during drilling in the future. In other words, such a drill will not last long.
Drill sharpening process
The drill is sharpened sequentially, first the back surface is processed. This must be done carefully, in several steps. The drill must be pressed firmly against the surface of the grinding wheel. It is necessary to pay attention to the sharpening angle, it must be unchanged. As a result of machining the back surface, the correct taper should be obtained when viewed from the side of the drill tip.
After that, the cutting part of the drill is processed. Here it is also necessary to strictly maintain the angle. And only after this operation is the final finishing of the rear surface made. It is necessary to monitor the jumper, it is located at the very tip of the drill. With proper processing of the drill, its size should not exceed 0.4 mm for drills with a diameter of 8 mm or less. If the drill is larger, then the size of such a bridge can be in the range from 1 to one and a half mm.
You should not be discouraged if it does not work out right away, such work is given only over time. It is best to practice on some others before you start sharpening the required drill. There are probably several pieces on the farm that have long been out of order and are just lying around among the trash.
The main thing is to get the skill of processing a drill on emery, to feel how to press, how to hold a corner. If you insert a sharpened test piece into a drill and start drilling, it will immediately become clear what mistake was made during sharpening.
It should be borne in mind that the drilling is not performed by the tip itself, but by the sides of the drill. Many people make the mistake of sharpening just one end of the drill without paying attention to the side edges. For sharpening drills with a victorious tip, there is a slightly different method, more complicated.
Drill sharpening for metal: how to properly sharpen a drill at home
It is impossible to perform high-quality metal processing (including drilling a hole in a metal part) without using a tool whose mechanical characteristics and geometric parameters correspond to the required values. That is why the question of how to sharpen a drill for metal correctly is relevant for home craftsmen, who often work with such a tool that wears out (which is natural) during operation.
Sharpening a drill for metal using a special device greatly simplifies the task
Drills designed for metal work have to be sharpened much more often than those with which woodworking is performed. When processing such a soft material as wood, the drills are practically not dull and can be successfully operated for a very long time, fully retaining their original characteristics. The situation is completely different with drills, with the help of which holes are made in metal parts. It is necessary to constantly monitor the condition of such drills and immediately take measures if their working part has undergone wear.
The fact that a drill for metal needs to be sharpened is evidenced by a number of signs:
- Creak and hum from a worn-out instrument;
- Intensive heating of the drill during its use;
- Poor quality of the holes created.
For drills with different cutting edge lengths, only one side works and the chips come out along one spiral flute
Working with a worn drill is not only ineffective but also unsafe. At any time, such a drill, on the working part of which significant loads are applied, can break, and its individual fragments flying in different directions at high speed can cause serious injury.
What is needed for the procedure
To sharpen a drill for metal yourself, you must first determine what tasks it will be used for. In production conditions, for sharpening drills, as a rule, special devices are used to ensure maximum accuracy and productivity of such a process. When sharpening drills at home, you always have to look for ways to make the result of this process of high quality.
The minimum set for sharpening drills for metal should include:
- Emery machine;
- Grinding wheels of various hardness, selected depending on the material of manufacture of the drill to be sharpened;
- A container for a coolant and the liquid itself, which can be used as ordinary water (or machine oil);
- Tools to maintain correct sharpening angles.
Drill sharpening stand mounts next to the abrasive disc to sharpen the cutting edge at a precise angle
When sharpening drills with your own hands, you need to pay attention to the following parameters:
- The angle between the plane of the front of the drill and the base of its cutting edge (this angle, measured in the main cutting plane, is called the front);
- Clearance angle, which is measured in the same way as the front angle, but along the back plane of the drill;
- Tool nose angle, measured between two cutting edges.
To sharpen metal drills in accordance with all the rules, you must adhere to the following values of the above parameters:
- The rake angle of the cutting portion 20;
- Rear corner 10;
- Apex angle 118.
If you need to sharpen a drill for metal in a production or at home, you must strictly follow safety precautions. This process is accompanied by the formation of a large number of sparks, from which it is necessary to protect the organs of vision. In addition, since this procedure is performed with sharpened metal tools, it should be carried out using gloves to protect the hands.
Drill sharpening parameters
Basic forms of sharpening twist drills
The most important parameters that should be considered in order to properly sharpen a metal drill with your own hands are:
- The angle at which the back of the tool is to the drilling plane;
- The angle of sharpening of the front surface of the cutting part;
- The length of the transverse bridge on the cutting part;
- Angle at the tip of the cutting tool;
- Length of cutting edges.
The main parameters of sharpening the drill
To sharpen the drill to be of high quality, it is necessary to ensure that it is fed into the processing zone at the required angle. To solve this problem, various devices are used, which are equipped with grinding machines.
It should be borne in mind: if the sharpening of the drill for metal is performed incorrectly, this can lead not only to a poor-quality result, but also to the breakdown of the tool.
Influence of nose angle on correct chip formation
An emery machine equipped with a grinding wheel is a universal device that allows you to sharpen a drill for metal with high quality even at home. Using such a device, the technological operation should begin with machining the flank of the tool. The drill to be sharpened is held in relation to the grinding wheel so that its cutting part is parallel to the surface of the wheel. This sharpening technique is ideal for metal drills with a diameter of less than 10 mm.
To sharpen drills with a diameter greater than 16 mm (including those equipped with carbide plates), it is best to use an emery machine with a special device. The use of the latter allows not only to control the angle of sharpening of drills of significant diameter, but also to carry out such a process with maximum safety.
Sharpening accuracy in a special device is achieved by precise fit and secure fixation of the drill in the arbor
Grinding machines equipped with accessories are recommended for use in cases where it is necessary to sharpen drills of the following categories:
- Used for drilling blind holes, which is characterized by a decrease in the axial cutting force;
- Universal, characterized by increased strength;
- Used for drilling deep holes and characterized by a small amount of undercut.
The main task solved by devices that allow high-quality sharpening of a drill for metal on a grinding machine is the correct orientation of the cutting part of the tool in relation to the surface of the abrasive wheel. That is why there is a special base plate in the design of such a device. The machine itself, the motor that drives the grinding wheel in rotation, as well as the turntable, on which the tool being processed is fixed, is installed on it. The use of such a column allows you to sharpen drills in almost any spatial position, positioning their cutting part in relation to the surface of the grinding wheel at the required angles.
Benefits of using special tools
A big advantage of using grinding machines equipped with special devices is that the movement of the tool being processed on them is provided by a drive connected to an electric motor. The structural diagram of such a drive includes a bearing assembly and a shaft. At the end of the latter, a drill is fixed, which must be sharpened.
Before starting the procedure, the tool is fixed on the device at the required sharpening angles. After the drill for metal is fixed on the movable column of the device, it itself is brought to the rotating grinding wheel. Thus, all the corners that need to be formed on the flank of the cutting part are automatically maintained during the sharpening process. Among the main disadvantages of such a drill sharpening machine, its large size is usually noted.
Drill sharpening machine
If you are looking for an answer to the question of how to properly sharpen a drill for metal without performing complex manipulations with the tool being processed, you can recommend more compact devices. One of these devices is a packing machine. It is installed on the spindle of a conventional electric drill, from which its main working element is driven by the grinding wheel. One end of such a device is equipped with a special coupling connecting the device with the rotating spindle of an electric drill, and the other with a cover with holes of different diameters into which the working parts of the drills to be sharpened for metal are inserted.
Sparta drill attachment for sharpening drills
It is very easy to teach someone to use this tool, which allows you to quickly sharpen a drill at home. At the same time, you may not even show such a process live or live, everything is clear and without demonstration. To sharpen a drill for metal using such a device, it is enough to insert the tool into the hole of the appropriate diameter until it stops and turn on the electric drill, which will rotate the grinding wheel. A tool sharpened with such a simple device has all the required geometric parameters.
It would seem that you can sharpen the drill using any device that can rotate the grinding wheel. Meanwhile, without the use of fixtures for fixing the tool in the sharpening process, such a procedure cannot be performed efficiently. It can also lead to serious injury. You can turn to this simplest sharpening method only if you need to sharpen small-diameter drills that are easy to hold in your hands during processing.
When sharpening manually, a corner fixed on the support will help to maintain the required parameters
After you have sharpened a drill for metal, it is necessary to perform such a technological operation as debugging. It is needed in order to bring the quality of the cutting part of the reconditioned tool to the required values. Lapping is done with fine-grain grinding wheels. At the same time, all irregularities are eliminated from the cutting part of the drill, it is given smoothness. Drills with no roughness on the working part create less friction during the drilling process, heat up less, which means they can last longer. Grinding wheels made of silicon carbide are used to perform finishing operations both in production and at home.
An important condition for high-quality sharpening is the absence of vibration of the abrasive stone
Drills, the working part of which is equipped with hard alloy solders, can also be sharpened, but a number of nuances should be taken into account. Carbide inserts are very critical of overheating, therefore, such metal drills can be sharpened qualitatively only at low speeds of rotation of the grinding wheel. In addition, when sharpening, care must be taken that the tool does not overheat. Otherwise, the carbide inserts will crack or even break off at the soldering point.
To sharpen carbide inserts, you can follow the processing technology of conventional cutting tools. It should also be borne in mind that diamond grinding wheels are used for sharpening drills with carbide inserts, since only they can effectively cope with the processing of such a hard material.
How to sharpen a drill for metal and concrete with your own hands
It does not require special evidence that the drill loses the sharpness of the cutting part during operation, that is, simply speaking, it becomes blunt. A blunt drill is not a bother until it is needed. Then it suddenly turns out that it is impossible to work with a worn out or blunt drill.
We can only regret that the geometry and size of the drill were not restored in time. This article will show you how to sharpen a twist drill as well as a hard-tipped drill bit for drilling concrete.
How to sharpen a spiral drill correctly
You don’t have to worry about sharpening a drill for wood, you can work with such a drill for many months and even years without any sharpening. Unfortunately, this cannot be said about a drill for metal, which must necessarily be sharp. That is, you can drill metal with an exceptionally sharp, well-sharpened drill.
A sharp squeak at the beginning of drilling is characteristic of the loss of drill sharpness. A drill not sharpened in time generates more heat and thus wears out even faster than a sharp one.
You can sharpen the drill on special machines or using tools. Naturally, if possible, it is preferable to do this on special equipment. But in the home workshop, as a rule, there are no such machines, so you have to use a regular electric grinder with a stone.
The main components of the twist drill.
The type of sharpening depends on the shape that should be given to the back surface of the drill and can be single-plane, two-plane, conical, cylindrical and screw.
The drill is sharpened along the back edges. Both teeth (feathers) of the drill should be sharpened exactly the same. It is not easy to do it manually. It is also not easy to manually maintain the desired flank shape and flank angle.
1. Single-plane sharpening of the drill is characterized by the fact that the back surface of the pen is made in the form of one plane. At the same time, the posterior angle ranges from 28-30. The drill is simply attached to the circle, so that the cutting part runs parallel to the circle and sharpening is performed without rotating, without moving the drill.
With such a sharpening, the cutting edges of the drill can be chipped during drilling, which is a disadvantage of this sharpening method. This is the easiest hand sharpening method and can be used for thin drills up to 3 mm in diameter.
2. Drills with a diameter of more than 3 mm should preferably be sharpened conically. It is difficult to perform such a sharpening manually without skills, but it is possible. The drill is taken with the left hand by the working part as close as possible to the intake cone, and with the right hand by the tail.
The drill is pressed against the end of the grinding stone by the cutting edge and the surface of the rear part, and is slightly wiggled with the right hand, while creating a tapered surface on the rear feather edge. The drill does not come off the stone during sharpening; hand movements are slow and smooth. For the second pen, everything is repeated in the same way.
Guide the drill with the cutting edge towards the grinding wheel.
We swing the drill to the bottom, and then up again.
When sharpening, try to maintain the original shape of the factory surface of the rear as much as possible in order to maintain the desired rear corners. If sharpening is done correctly, then on drills with a diameter of up to 10 mm, it is quite sufficient. For diameters above 10 mm, this sharpening can be improved by sharpening the front surface as shown in:
Anterior surface sharpening.
What is the point of undermining? By reducing the rake angle and increasing the cutting edge angle, the chipping resistance increases, which increases the drill life. In addition, the width of the transverse edge becomes smaller. The transverse edge does not drill, but scrapes metal in the center of the hole. The second figure clearly shows that here it is shortened, which makes drilling easier.
For drills with a selected small clearance angle, you can additionally sharpen the clearance surface. In this case, the drill rubs less than the back surface in the drilling hole. Cm. :
Back surface undercut.
In production conditions, after sharpening, as a rule, finishing is done, which smoothes the surface, removing small jags. The drill, on which the finishing is done, wears out less than just a sharpened drill. If possible, fine-tuning should be done without fail.
For finishing, you need to use grinding round stones from green silicon carbide (grade 63C, grain size 5-6, hardness M3-CM1) on a bakelite bond, as well as circles from Elbor LO (grain size 6-8) on a bakelite bond.
Sharpening of products of a different design
Apart from twist drills, tools of other designs are used for metal processing. At home, you can debug the following tools.
How to sharpen a drill for metal
A properly selected device will significantly reduce time costs and perform the work as accurately as possible. Find out below how to sharpen a metal drill on a sharpener.
In addition to the main unit with an electric motor and a circle, you will need to purchase special devices that hold the drill in a stationary state. Such stands allow you to control the angle of inclination and tool feed during turning.
Many devices allow debugging of cutting products for metal with a diameter of 3 to 19 mm. For turning twist drills, you can use special machines that have a built-in electric motor and a feed mechanism.
Unlike using a conventional sharpener and holder, professional equipment can cost tens of thousands of rubles. Therefore, if sharpening drills is not a profession, then you can get by with the use of the above-described tandem of a grinding wheel and a holder, or edit the tool manually.
It is possible to sharpen the drill with a file without experience. The main thing is to choose the right file. Considering the fact that even cheap drills are made from high quality cutting steel, you will need to choose a diamond-coated file. In addition to the file, you need to prepare a vice in which the tool should be fixed.
In order not to waste time and energy on the manual method, you can use a grinder with an abrasive wheel.
Sharpening with a drill bit
Without an emery machine, using a special drill attachment, you can perform the operation efficiently and with less time.
For beginners, this is the preferred method. Drill sharpening is performed as follows.
- Install the nozzle on the drill;
- The drill is inserted into a hole of a suitable diameter;
- The drill turns on and the product is sharpened on one side;
- By turning the drill 180 degrees, the opposite edge is sharpened.
To use your device effectively, consider the following:
- Only slightly dull tools are sharpened with the drill bit. If there is deep damage to the cutting surface and when the drill was overheated, it will not be possible to restore the product.
- The sharpening angle in such devices is fixed. Therefore, to restore drills for working with non-ferrous metals, you will need to purchase an original device, or to refine the products with a file.
How to sharpen a drill bit for metal with different tools
Sharpening metal tools allows them to fully restore their functionality. The operation can be performed using various accessories.
How to properly sharpen a drill for metal and not spoil the cutting surface of the product will be described in the publication.
Drill sharpening with grinder
There is a sander in almost every home workshop, so the method will be one of the most budgetary.
In addition to a grinder with an installed grinding wheel, for work, you need to prepare a vice in which the drill will be held during sharpening. The room where the tool is being debugged should be light so that the process of removing metal from the cutting surface can be controlled.
Debugging is carried out in the following sequence:
- The drill is installed in a vice in a vertical position;
- A part of the trailing edge is removed with a grinder to completely eliminate traces of wear;
- The cutting edge is sharpened at an angle of 120 degrees.
To prevent the drill from overheating during the turning process, the contact of the emery wheel with the metal should last no more than 2 seconds. Repeating the removal of a small amount of metal from the working edge many times, it is possible to adjust the tool to the required angle.
It is more convenient and safer to work using a grinding wheel and a special holding device.
How to sharpen small items
Unfortunately, to sharpen a thin drill using mechanized methods, including drill bits, is unlikely to work. All work to restore a small diameter product will need to be done manually.
The first attempt may fail, so you should first select an inexpensive thin drill in need of restoration and perform the operation on it. You will also need a small diamond file and glasses with 4x magnification to work.
The process takes place in the following sequence:
- The drill is ground down by about 1 mm;
- A file is used to consistently sharpen the edges of the tool at the required angle.
The whole operation is performed by eye; it is important to use magnifying glasses and a powerful lighting device when working.
If the first attempt was unsuccessful, you should know that any skill can only be developed within a certain period of time. In case of failure, do not give up trying to learn a useful skill like sharpening fine drills with your own hands.