The fact that during operation a metal drill has the unpleasant property of becoming duller does not require special proof. Moreover, this happens the faster the more often the drill is in use and the greater the amount of work it performs.
A metal drill becomes dull after short use and requires sharpening.
Many people do not pay attention to this and continue working until the drill has completely become unusable, after which they throw it away and buy a new one. This happens because the owners simply do not know how to work with metal. Meanwhile, this can be done at home, using the devices and tools available in almost every home workshop.
Signs of a dull drill
If a sharp squeak is heard when the drill comes into contact with the metal, it means the drill is dull.
You can only drill into metal with a very sharp tool. If at the beginning of drilling you hear a sharp creak at the point of contact between the tool and the metal, then this is a sure sign that the drill is dull. If you hear such a nasty sound, it is better to stop working. Otherwise, the tool, as it rotates, will rub against the metal more strongly and, accordingly, generate more heat during the drilling process. The working edge of the drill will wear out faster due to friction and heat.
Home craftsmen mostly use small drills for their needs, Ø no more than 16 mm. To sharpen a dull tool, it is better to use special equipment. But it is quite expensive, so it is rarely purchased for home use. But in any home workshop you can construct a sharpening device from the tools at hand. Sharpening can be done using:
- a grinding machine with an abrasive wheel;
- grinding machine;
- electric drills with replaceable attachments.
You can use any other sharpening device that you can place a sharpening stone on and make it rotate. It is only necessary that such a device can provide a shaft rotation speed of up to 1500 rpm.
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Preparing for work
For your safety, use protective gloves and goggles when sharpening drills.
But before you start working, you need to put on safety glasses and gloves and prepare a container of water. These are mandatory protective devices, without which to sharpen metal tools very dangerous.
During operation, sparks and microscopic metal dust particles fly off from the sharpener and tool and scatter in different directions. If you do not protect your hands and face, these microscopic particles can cut quite sensitively on exposed skin. But they pose a particular danger to unprotected eyes. Once in them, metal dust particles cause serious vision problems, including complete vision loss.
A container of water is needed to cool the tool being sharpened, because during sharpening it becomes very hot from friction against the rotating plane of the circle. If the drill is not cooled in time, it will inevitably overheat and will quickly break during operation.
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Sharpening technique and sequence
But prepared tools and protective equipment are only half the battle. You can't take on a job without knowing how. After all, this process, although simple, requires strict adherence to the sharpening sequence. It is also very important to initially correctly decide on the type of sharpening. The type is determined by the shape that needs to be given to the cutting edges (“feathers”) of the tool. There are single-plane, double-plane, conical, cylindrical and screw types of sharpening.
To determine whether a drill is sharpened correctly or incorrectly, you need to carefully examine it after sharpening. Factors of correct drill sharpening and the following: it must remain symmetrical about its axis. Its cutting edges must have the same length relative to the axis of the drill and the same sharpening angles.
Sharpening always starts from the back surface of the drill. The surface must be pressed tightly against the grinding wheel, maintaining the initially specified angle throughout the process. Without the skills, it is very difficult to do everything correctly the first time, so be prepared to have to do several approaches. After each approach, you should carefully inspect the surface being sharpened. Work continues until the back surface looks like a regular cone when viewed from the side, at eye level.
Only after achieving the desired result can you begin to sharpen the cutting part. When performing it, you need to strive to ensure that both “feathers” are sharpened absolutely identically. It is also very important to maintain the correct sharpening angle when working.
With single-plane sharpening, the back surface is processed as one plane, maintaining an angle in the range of 28-30 °. This is one of the most simple ways which is used for fine instruments, with a diameter of up to 3 mm.
When performing work in this way, the drill is pressed at a given angle to the grinding wheel. While sharpening, the tool does not turn over and moves. This often leads to the fact that the cutting edges of the drill may crumble, especially if the metal is of low quality.
It is preferable to sharpen the cutting part of larger diameter drills conically. It's more the hard way, and if for some reason you value the tool you sharpen, then first it’s better to practice on some broken surface to “get” your hand.
The technique of this method is as follows: with your left hand you take the tool by the working part, and with your right hand - by the tail. You need to keep the working part as close to the intake cone as possible, otherwise high-quality sharpening will not work. In this position, the drill is pressed not only by the cutting edge, but also by the surface of the rear part against the end of the sharpener. Holding the tail with the right hand, the drill is slowly and smoothly rocked so that a conical surface is formed on the back edge of the drill. After finishing sharpening one feather, the instrument is turned to the other sharpener, and everything is repeated all over again. Very important nuance for this method: the drill should never be removed from the sharpener while sharpening the pen.
There is another conical sharpening technique. The drill is also taken by the working part with the left hand, and by the tail with the right hand. But the drill is pressed to the end of the sharpener only by the cutting edge, and then during operation, without lifting it from the sharpener, the tool smoothly rotates around its axis, achieving uniform and high-quality sharpening of the back surface.
With this method of sharpening, a cone will be obtained on both sides on the back surface of the pen, but the drill will remain without a ground corner. Therefore, during operation, such a drill will rub more against the metal and, accordingly, heat up more.
Work good tool it's convenient, effective and correct! Today we have useful homemade product for the home and garage - a homemade machine for sharpening drills. Correctly sharpening a drill presents some difficulties without experience. Moreover, drills of large diameters (somewhere from 6mm) can still be controlled by sharpening and, at the very least, they can be sharpened after some time. Drills of small diameters, especially in demand by masters of radio and electronic equipment, have to be sharpened literally by touch and under a magnifying glass and without the use of mechanization using corundum blocks. By the way, just recently we published the article “If you haven’t read it, be sure to read it!
Using my deposits of illiquid assets and conducting a review of the Internet, I collected a quick fix A simple device that allows you to sharpen drills from 2.0 to 6.0 mm without much difficulty. Further improvement of the device is possible and is a task for the near future. General form in photos 1 and 2.
As, of course, it is known that metal drills have a sharpening angle at the tip of 120 degrees. (Less for wood and soft metal). The photo shows a yellow square lying between the sharpener and the device, ensuring this angle, i.e. the drill is located at an angle of 60 degrees. to the working end of the abrasive disc. The required angle of the drill head is ensured by the initial inclination of the drill relative to the disk.
The operating principle of the device is not new and has been repeated many times and published online. The difference between this device is the use of so-called jewelry vises, which are commercially available and inexpensive, to secure the drill. I had some very old ones, altered and worn out after 30 years of use. Photo taken from the network.
The principle of operation is simple - by turning the handle we move the jaws apart and by turning them in reverse we clamp something, for example a drill.
These vises have been modified. The rivets were also drilled onto these seats the plates were installed and re-riveted with longer rivets. It will become clear later why this was done.
The drill is clamped in a vise so that the cutting edges lie parallel to the jaws.
Along the edges of the riveted plates, coaxial holes are drilled at the same distance from the center and lying on a straight line perpendicular to the axis of the vise (that is, to the drill). An axis will pass through these holes on which this “rocking chair” will swing alternately when sharpening one and the other edge. With ideal marking of the rocking chair, equality will be achieved cutting edges when sharpening.
The rocking chair is mounted on racks (the housings of mortise door latches without internals are suitable. In turn, the racks are screwed to an oak block. It also contains four support legs to adjust the desired height.
The rocker with the drill is placed between the posts on an axle; the axle is removable. 
Sharpening the first edge (jaws are painted over with a blue marker).
The sharpening of the second rocking edge is turned 180 degrees. (the painted side is not visible). Top view of this node.
The finished drill is pictured below. Errors that arose when working “on the knee” and old worn-out vices did not allow sharpening drills from 1 mm. Shown here is a sharpened 1.5mm drill bit. At high magnification, the difference in the lengths of the cutting edges is visible (small, but there)
You need to keep your drill bits sharp and special machine You won’t find one with fire during the day even in specialized stores? And make a machine for sharpening drills with your own hands. You can easily cope with assembling a simple structure if you have at least a little experience in working with basic tools.
Homemade machine
A drill sharpening device can be of great value in household since with the help of this device you can independently sharpen drills of any diameter and type. In addition to making a special unit, you will need an electric motor with a grindstone.
Basic materials:
- Metal plate with holes – 1 pc.;
- Bolt or stud 70x15 mm long;
- Set of washers;
- Corner – 30x30 or 40x40;
- Plates – 3-4 mm thick;
- Cotter pin – 30x1.5 mm;
- Clamps.
In addition to materials, you will need tools for their machining and connections, in particular electric welding and grinder.
Tools:
- Electric welding.
- Drill.
- Bulgarian.
- Hammer with impact attachments.
- Special clamps 2 pcs.
- Spanners.
- Pliers.
Manufacturing process:
1. Making the mounting plate
The mounting plate is made of a metal lining with holes about 3-4 mm thick. On one side, the part is cut off by 3 centimeters, while during cutting it is necessary to save the finished hole. The cut part will be needed to make the next part sharpening device, and a large element for lining when installing the product on the table.
2. Angle for fixing the drill
The element is designed to fix the drill during sharpening. It is made by cutting off part of a regular 30x30 or 40x40 corner. The total length varies between 60-90 mm, while the extreme part is cut at an angle of 60 degrees to give the sharpened plane the desired level.
3. Fastening for fixing angle
The cut-off part with a hole from the plate is connected to another metal plate, while the elements are superimposed on each other and electric welded to the corner. For welding, a mounting cutout should be cut on the plates in order to install the parts end-to-end and weld them.
A hole is drilled in the connected parts to the diameter of the bolt or stud, and the parts themselves are carefully welded on all sides to impart rigidity.
4. Welding the bolt
A bolt or pin is designed to fix the angle. The element is welded at an angle of 75 degrees to the main plate. During scalding, the lower plane should be taken into account, and if necessary, remove slag to prevent distortion of the product.
5. Attaching the washer to the bolt
The washer is installed on the bolt at a level of 25 mm from the upper extreme part. The approximate diameter is 30 mm. The element is welded using electric welding in the desired design position, observing all plane levels.
6. Hole in the stud
If there is no hole for installing a cotter pin in the bolt (stud), you need to make one using a drill and drill bit required diameter. This technical element will be used to secure the fixing angle. The diameter may vary, but the main condition is reliable fixation.
7. Drill stop
It is made of a metal rod and a special vice clamp. The rod is welded to the fixing angle from below. The clamping mechanism is mounted on a rod, and the device should be equipped with a special cup-support for the drill from a corner.
The system is mounted on the grinding table and secured with additional clamps.
Video: how to make a device for sharpening drills.
Drill sharpening machine
This method is available to anyone. For this you will need a drill. Perhaps not right off the store counter, but already obsolete and not used by you. It will act as a motor.
It needs to be secured to the frame, a bushing or a ready-to-install grinding wheel or a universal fine-grained disc must be inserted into the chuck. All. When you turn on the drill, you get a rotating abrasive on which sharpening the drill is a pleasure.
A very simple sharpening solution. However, do not forget about the devices for sharpening the drill, which fixes the element being sharpened relative to the sharpener.
It is impossible to perform high-quality metal processing (including drilling a hole in a metal part) without the use of tools, mechanical characteristics And geometric parameters which correspond to the required values. That is why the question of how to sharpen a metal drill correctly is relevant for home craftsmen who often work with such a tool, which wears out (naturally) during use.
Sharpening a drill for metal using a special device greatly simplifies the task
Drills intended for metal work have to be sharpened much more often than those used for wood processing. When processing such soft material, which is wood, drills practically do not become dull and can be successfully used very long time, fully maintaining its original characteristics. The situation is completely different with drills, which are used to make holes in metal parts. It is necessary to constantly monitor the condition of such drills and take immediate action if their working part is worn out.
A number of signs indicate that a metal drill needs to be sharpened:
- creaking and humming noise produced by a worn-out instrument;
- intense heating of the drill during its use;
- low quality of created holes.
Working with a worn drill is not only ineffective, but also unsafe. At any moment, such a drill, the working part of which bears significant loads, can break, and its individual fragments scatter in different directions from high speed, can cause serious injury.
Drill sharpening parameters
Both in industrial and at home conditions, metal drills can be sharpened on emery machines equipped with a sharpening wheel of appropriate hardness. It is best to use commercial equipment in such cases. If it is not available, then you can sharpen drills on devices made by yourself. It should be borne in mind that the characteristics of this equipment, as well as the devices for sharpening drills used in conjunction with it, largely determine the quality of such a procedure.
Most important parameters things to consider in order to properly sharpen a metal drill with your own hands are:
- the angle at which the back of the tool is positioned to the drilling plane;
- sharpening angle of the front surface of the cutting part;
- length of the transverse bridge on the cutting part;
- apex angle cutting tool;
- length of cutting edges.
In order for the drill to be sharpened with high quality, it is necessary to ensure that it is fed into the processing area at the required angle. To solve this problem, various devices are used that are equipped with sharpening machines.
It should be kept in mind: if sharpening a drill for metal is done incorrectly, this can lead not only to a poor-quality result, but also to breakage of the tool.
What is needed for the procedure
To sharpen a metal drill yourself, you must first determine what tasks it will be used to solve. In production conditions, for sharpening drills, special devices are usually 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 high-quality.
The minimum set for sharpening metal drills should include:
- emery machine;
- grinding wheels of varying hardness, selected depending on the material of the drill that needs to be sharpened;
- a container for coolant and the liquid itself, which can be ordinary water (or engine oil);
- devices to withstand correct angles sharpening.
When sharpening drills with your own hands, you need to pay attention to the following parameters:
- the angle between the plane of the front part of the drill and the base of its cutting edge (this angle, measured in the main cutting plane, is called the front);
- rear angle, which is measured in the same way as the front angle, but along the rear plane of the drill;
- tool tip angle measured between two cutting edges.
To sharpen drills for metal, according to all the rules, you must adhere to the following values of the above parameters:
- front angle of the cutting part – 20°;
- back angle – 10°;
- apex angle – 118°.
If you need to sharpen a metal drill in production or at home, you must strictly follow safety precautions. This process is accompanied by the formation large quantity sparks, from the effects of which it is necessary to protect the organs of vision. In addition, since this procedure is performed with sharply sharpened metal instruments, it should be carried out using gloves to protect your hands.
An emery machine equipped with a grinding wheel is universal device, which allows you to sharpen a drill for metal with high quality even at home. Using such a device, the technological operation should begin with processing the back surface 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. Sharpening performed using this method is optimal for metal drills whose diameter does not exceed 10 mm.
To efficiently 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 sharpening angle of drills of significant diameter, but also to carry out this process with maximum safety.
Sharpening machines equipped additional accessories, it is recommended to 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 axial cutting force;
- universal, characterized by increased strength;
- used for drilling deep holes and characterized by a small point size.
The main task that is solved by devices that allow high-quality sharpening of a drill for metal on sharpening machine, is the correct orientation of the cutting part of the tool in relation to the surface. That is why the design of such a device has a special base plate. The machine itself, the motor that rotates the grinding wheel, and the rotary column on which the tool being processed is fixed are installed on it. The use of such a column allows you to sharpen drills in almost any spatial position, placing them cutting part relative to the surface grinding wheel at the required angles.
Benefits of using special devices
The big advantage of using sharpening machines equipped special devices, is that the movement of the tool being processed on them is ensured by a drive connected to an electric motor. Structural diagram Such a drive includes a bearing assembly and a shaft. At the end of the latter there is a drill that needs to be sharpened.
Before starting the procedure, the tool is fixed on the device at the required sharpening angles. After the metal drill is fixed on the movable column of the device, it itself is brought to the rotating grinding wheel. Thus, all the angles that need to be formed on the back surface of the cutting part are maintained automatically during the sharpening process. Among the main disadvantages of such a machine for sharpening drills, its large size is usually noted.
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, we can recommend more compact devices. One such device is a nozzle machine. It is installed on a conventional spindle electric drill, from which its main working element, the grinding wheel, is driven into rotation. One end of such a device is equipped with a special coupling that connects the device to the rotating spindle of an electric drill, and the other is equipped with a cover with holes of different diameters into which the working parts of metal drills to be sharpened are inserted.
It is very easy to teach someone how to use this device, which allows you to quickly sharpen a drill at home. In this case, you don’t even have to show such a process on video or live, everything is clear without demonstration. To sharpen a drill for metal using such a device, it is enough to insert the tool into a hole of the appropriate diameter until it stops and turn on the electric drill, which will rotate the sharpening wheel. A tool sharpened using such a simple device has all the required geometric parameters.
It would seem that you can sharpen a drill using any device that can rotate a sharpening wheel. Meanwhile, without the use of devices for fixing the tool during the sharpening process, it is impossible to perform such a procedure efficiently. In addition, serious injuries may occur. You can use this simplest sharpening method only if you need to sharpen small-diameter drills that are easy to hold in your hands during processing.
At manual sharpening A corner attached to the support will help you maintain the required parameters.
Dull drill bits may break during operation and injure you. It is much better and easier to work with sharp ones. In this manual you will find drawings and a device for sharpening drills.
Step 1: Comparison of sharp and dull drill bits
The left side is blunt. This can be seen by the light reflection on the cutting edge between the two grooves. The photo on the right shows a sharp cutting edge.
Step 2: Sharpening Tool
Experienced people know how to sharpen drills with their own hands. In theory, the shank should be kept in right hand at an angle of 59° relative to the drill sharpening device. When the drill touches the sharpener, you need to move the shank further down to the left, while at the same time turning the drill around its axis clockwise. I've never succeeded in doing this.
I bought the sharpening tool you see in the photo almost thirty years ago. Such simple devices for sharpening drill bits are still sold at almost the same price.
Step 3: Set the degree
The guide on the stand can be installed in seven positions. My drills have a cutting edge angle profile of 59°, you need to set this degree on the guide. Tighten the wing nut.
Step 4: Align the Edge
The sharpening tool has a small pointed tip, and the edge of the groove needs to be set against it. The tip can be lowered or raised to bring it to the edge of the groove.
Step 5: Offset Amount
First you need to set the offset (the distance between the yellow lines), it must be equal to the radius (the distance between the green lines).
Step 6: Width and Angle of Cutting Edge
Pay attention to the angle of the red line. If you took the drill too far in the previous step, the cutting edge will move closer to the tip. The edge was too wide and the profile too flat. Because of this, it will slide along the surface of the metal and it will be difficult for you to drill. You can reduce the offset a little, but only a little, otherwise you may accidentally damage the sharpening tool tip on the stand's sharpening wheel.
Step 7: Ideal Cutting Edge Angle
Ideally, the edge should be as small as possible. It will be the lower point between the beveled edges of the drill grooves, indicated in the photo by a yellow line, this drill will cut metal very well.
Step 8: Clamp
Once you have the stem aligned, tighten the mounting screw.
Step 9: Set the length
Set the sharpening guide to the length of the drill. The end should be in the moving tray and not hanging in the air. Loosen the metal painted nut. Adjust the black nut. Tighten the painted metal nut.
Step 10: Setting the Height
The shank should be at right angles to the grinding wheel. For sharpening I use a radial cutting machine. The tip must be aligned with the center of the grinding wheel axis.
Step 11: Attach the machine to the table
The bit should only lightly touch the grinding wheel. If you press too hard, it will be very difficult to sharpen. It will overheat and you will remove too much metal.
The base of the sharpening guide should be at right angles to the grinding wheel (green line). And turn the upper part of the guide so that the tip points slightly to the left of center (the angle between the green and yellow lines). Move the machine forward until the drill bit touches the surface of the grinding wheel. Fix the machine on the table.
Step 12: Get Ready to Sharpen
Turn the tip to the right. Turn on the grinding wheel.
Step 13: Sharpening
Slide the tail of the guide to the right (red arrow) until the drill touches whetstone. Yellow wavy lines represent sparks. When the drill is in this position, it will actually be sharpened.
Step 14: Rotate the Bat
Continue moving the tail of the guide to the right until the drill bit clears the edge of the stone. To sharpen the other side, you need to turn it around its axis half a turn.
First turn off the machine. Then loosen the fastener and turn it half a turn. The edge of the groove should be flush with the sharpening tip. Repeat the previous two steps.
Turn off the machine. Pull it out of the mount. Check the width of the cross cutting edge. If you are unhappy with the quality of the sharpening, change the stem and repeat the process.
Step 15: Sharpened Drill
The photo shows a good sharpening. The cutting edges are not worn or rounded, they are sharp and crisp. The length and angle of the transverse cutting edge are also quite good.
Step 16: Fine Drill Bits
Such sharpening tool good for 3mm and larger. If it is thinner, it will no longer be possible to sharpen it using this device.
To sharpen thin ones, make a special block from wooden block approximately 10 cm long. Please note that the angle between the red lines is 77°.
Step 17: Angle between the edges of the wood block
Side view of the block. The angle between the red lines is 59°.
Step 18: Guide Line
A triangular cutout is visible on the upper plane of the bar. This cut goes along the entire upper edge of the block and serves as a bed. The angle between the red lines is also 59°. The edges of the triangular cut are used to align the cutting edges. You can check the edges by eye.
Step 19: Attach it to a block
Place the drill bit into the cut on the block. Place the block in the vise so that the shank is above the grip and the grip extends slightly beyond the beveled side of the block. Turn so that one of the cutting edges aligns with the guide edge of the triangular cutout. Secure with a clamp. Drop a little oil onto the sharpening stone. Slide along the beveled side of the device, thereby sharpening the drill.
When the sharpening stone stops removing metal, turn the drill half a turn and sharpen the other edge. Check homemade sharpening You can use a magnifying glass if necessary.