A simple device for sharpening drills with your own hands. A device for sharpening drills should be in the arsenal of any home craftsman Homemade tool for sharpening drills
Drilling metal or wood is a job that you do regularly. A high-quality nozzle does not require sharpening for quite a long time, however, there are some mistakes in which dulling occurs ahead of schedule:
- Using a drill that is not suitable for the material being processed. This does not necessarily mean drilling into reinforced concrete with a wood drill, although in this case you will instantly turn the cutting tool into a rod with a rounded end. For drilling various types For metal and hard plastics, there are specially made drills. If there is a discrepancy, the cutting edge quickly becomes unusable;
- Incorrect sharpening angle. This value must also correspond to the type of material in which the hole is made;
- Overheat. The most common reason. When working with durable material, we want to finish drilling quickly, and we often forget about such a little thing as cooling the work area. If it is not possible to supply coolant to the tool, it is necessary to take breaks to cool the cutting edge. You can dip a hot drill into a container of water.
The mechanism of hot blunting is simple: the hot edge “releases”, that is, it loses its hardness. Cutting properties deteriorate, which leads to increased friction. Heating increases more strongly, and the process worsens in arithmetic progression.
As a result, we may lose a good and possibly expensive instrument. If you have it on hand grinder for drills, the problem is solved on the spot; if not, you have to invent your own sharpening methods.
Manual sharpening without tools
A mechanic with extensive experience sharpens drills by hand, using only a sharpener with a tool. But not all home craftsmen can boast of such skills.
In addition, this method can only restore the sharpness of products large diameter. Then it is easier to control the angle. The most popular size (3-5 mm) cannot be sharpened this way. Even a template won't help here.
Craftsmen who regularly carry out drilling work will be interested in the variety of sharpening machines for drills offered in power tool stores.
However, such devices (despite the obvious ease of use) are quite expensive pleasure. So the “homemade” people run to the store for another Chinese tip. But experienced home craftsmen still use tools from the times of the USSR, which meet GOST standards in terms of strength and durability.
The secret is simple - many old-school locksmiths have in stock homemade machine for sharpening.
IMPORTANT! For most household projects, you can get by with simple sharpening tools. Especially if the word “machine” scares you.
The simplest devices for straightening the cutting edge of a drill
To understand the process, let's take a look at components tip.
Then, by turning the stock, a plane (more precisely, a cone) of the back is formed.
The sharpening is checked on a template and assessed visually. All planes comply with the standard.
A guide is welded to the bottom (rear) part of the angle stock to support the drill shank. The stop itself is welded from a coupling and an angle.
Fixation is done using a screw. The stop sets the maximum size of the edge to be ground, and thanks to this, both cutting elements of the drill are ground symmetrically.
The working edge is sharpened against the direction of rotation of the sanding wheel. In this case, the resulting burr is automatically removed by the running surface of the emery. For sharpening, two or three swings of the stock along the radius of the backing cone are enough.
This type of drill is sharpened along the outer surface of the emery stone; if necessary, use the lateral (radial) plane - the device can be rotated to any angle.
The drill sharpening machine is attached to the workbench using a clamp. You can fix the base permanently, but in this case you will lose the possibility of precise adjustment.
The technological process of mechanical processing of materials includes many different operations, which require high-quality and sharp tools. Thus, in a machine shop 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, each of which has a specific sharpening method.
Features of drills
Mechanical processing of metal involves enormous 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, in a turning tool or a disk cutter everything is clear 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 taken into account before sharpening a drill for metal, because an incorrect cutting angle will lead to vibration and breakage.
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 will you need for sharpening?
At the enterprise, everything necessary for instrument restoration is always at hand. But the home craftsman has to look for an alternative to high-quality factory devices in more simple solutions, which can be used in a regular garage. And yet, before sharpening a drill for metal, stock up on the minimum set:
1. Grinding wheel. It must be installed on a rotating shaft. The device is popularly known as “emery”. It is very common in the garage.
2. Coolant container.
3. Coolant (water or engine oil).
In order to maintain the angle drill sharpening But maybe such a set is not enough. After all, you will have to control the process “by eye,” which is unlikely to happen without the presence of certain experience. In this case, the basic kit must also include a device for sharpening the drill, which you can buy or make yourself.
Controlled parameters
When everything is ready, you need to familiarize yourself with some theory in order to have an idea about the main parameters of the axial cutting tool. Before you sharpen a drill correctly, you need to know its angles:
1. Front. Defined in the main cutting plane (runs perpendicular to the main cutting edge) as the angle between the rake surface and the main plane (perpendicular to the cutting speed vector). It is directed tangentially to the drill circumference.
2. Rear. Also defined in the main cutting plane as the angle between the flank surface and the cutting plane (passes through the velocity vector and the cutting edge).
3. Apex angle located between the two main cutting edges when looking at the drill from the side.
The optimal value of the front angle is 18-20 degrees, the rear angle is 10-12. The tip angle in metal drills has a standard value of 118 degrees.
Sharpening process
Now let's talk about how to sharpen a metal drill using regular sandpaper. The main sharpening of this axial tool is carried out along the rear surface. To do this, turn on the emery, firmly grasp the drill in your hand so that the main cutting edge is directed towards the rotation of the sharpener. Now we bring the edge to the sharpener, after which we turn the drill by the shank so that the cutting edge is parallel to the surface of the circle. We perform 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 sharpen the front surface. As a result, the rake angle decreases, which means the thickness of the blade (the so-called cutting edge angle) increases and, accordingly, the service life of the drill.
Sharpening using a jig or machine
The method described above can be called artisanal, since precise control of the drill parameters directly during sharpening is simply impossible to achieve. IN best case scenario you will check the angles after finishing sharpening, and in the worst case, just check how much better the drill has become. How to sharpen a drill correctly?
Of course, for this it is better to use more advanced options that will allow you to adjust 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 tool sharpening is required constantly, then purchasing a machine would be optimal. It will significantly simplify the process, especially if you need to resharpen carbide drills for metal. The main advantage of its use is the exact adherence to predetermined parameters. When there is a large volume of work, it is unacceptable to use an incorrectly sharpened tool, as this will lead to a decrease in productivity. Modern sharpening machines allow you to obtain Various types drill sharpening:
1. X-type. Mainly used for drilling blind holes. Designed to reduce axial cutting force.
2. XR type. Used for universal drills. The penetration into the material is somewhat worse than in the first type, however, such drills have increased strength and durability.
3. S-type. The point described above is used here, which also allows you to increase the service life of the drill during processing various materials(from cast iron to stainless steel).
4. N-type. A point is also used, but of a smaller size. Drills with this sharpening are used for deep drilling.
Device design
As has already become clear, manual sharpening drills are the work of a professional who not only knows the correct angles, but also feels the cutting process. Unfortunately, such an instinct comes only after many years of practice working with a drill press or drill. There is no need to experiment, as you can make it yourself or purchase a sharpening device. In both cases it will include the same structural elements and work according to the same principle.
So, the main task of the device is the correct orientation of the drill relative to the plane 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 sharpener is located. The plate also contains a rotating column on which the drill is fixed. It must be able to not only rotate, but also move towards the grinding wheel.
Any bearing assembly with a shaft can be used as a column, for example from old drill. A drill bed is fitted onto 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 when initially setting up the device, the drill tip angle is maintained at 118 degrees.
Sharpening with attachments
Another simple and convenient method involves using a device such as a drill sharpening attachment. Its main advantage is its versatility and ease of use. The device has a cylindrical shape. On one side there is a connecting unit, through which the attachment is installed on the drill spindle. On the other side there are holes for installing drills of a certain diameter. To sharpen, the drill is inserted into the hole, after which the sharpening mechanism is driven by the drill motor.
Security measures
Drill sharpening is associated with the formation of small particles that come off the sharpener during wear. They heat up and fly in different directions in the form of fiery sparks, so for safety you should use safety glasses and gloves.
When sharpening a drill without a jig, make sure to securely fix its position. Otherwise, upon contact with the sharpener, it may simply be torn out of your hands.
Drills must be of high quality and well sharpened by a professional craftsman. In the old days, drill sharpening was done by hand.
Today, special devices for sharpening drills have appeared, and their design is very simple.
Why is sharpening needed?
If the drill becomes dull, it is very difficult, and sometimes impossible, for them to drill through the surface. It is also worth noting that for different types drill surfaces must have a certain sharpening angle, for example, for a plastic surface the angle will be 30 degrees, for hardened steel this angle will be 130 degrees.
In cases where a perfectly drilled hole is not required, the sharpening angle can be 90 degrees.
How to properly sharpen a drill
You can sharpen the drill yourself using abrasive discs. During sharpening, the drill must be held by work surface. You need to hold the tail of the drill with your other hand.
From the side, the drill must be pressed against the abrasive disc. Then it is advisable to turn it with extreme care, as a result the cutting edge will take the required angle and structure.
Sharpening the drill must be done on each side separately. It is also necessary to ensure that the tip of the drill is located exactly in the center when sharpening the cutting part. This must be done correctly, as an error in sharpening can cause the drill to skewer to the side.
Do-it-yourself drill sharpening is not the best good way, since it is capable of carrying with it a number of inaccuracies, for example, the cutting edges may not be correct in relation to the tool axis.
Sharpening device
The device is designed for sharpening blind or through drills made of cast iron and steel. This device is made taking into account the types of sharpening, as well as its size. It is easy to change the sharpening angle on the machine.
There are two types of devices that will help sharpen a drill: a household and an industrial machine. In the first case, the sharpening device takes up little space and fits perfectly into the home, but such a machine can only sharpen small drills.
Industrial machines that are made to sharpen drills with large diameters have great power. The industrial machine has a clamp and a sharpening wheel.
With this device, drill sharpening occurs under the supervision of an operator who can easily control the process. Such devices are designed for long-term operation.
How to make a machine for sharpening drills with your own hands
We will need following materials: abrasive disc, switch, motor with good power, stand, wires, axle and plug. Also for safe use The machine must have a housing, outside of which it is necessary to place an axis with an abrasive wheel for operation.
You first need to decide on the installation location of the machine, since it will be connected to an outlet.
Also, our device should be placed on a table, preferably made of metal, where the engine will need to be placed, and marks should be placed for making holes for the bolts.
An abrasive disc is placed on the motor shaft. To secure it to the shaft, you must first put on the washer, then the disk, and then the washer again. After this, you should install the fastening nut on the pre-prepared thread on the shaft.
An engine from washing machine. The power of its motor will be sufficient for the process of sharpening drills. Wires can also be taken from improvised equipment.
Note!
You need to connect the wires to the starter, which should have three open contacts. The winding must be capable of connecting phase lines using two starters connected in series.
The off button should be connected to NC, and the start button will be connected to NO, and it should also be in parallel connection with two NO contacts of the starter.
When you press the power button, voltage will be applied to the winding and as a result the circuits should close. When the button is released, the voltage supplied to the starter should not be removed. When disconnected, the engine must stop.
The engine itself safe device, but to protect its mechanisms from dust it is necessary to make a frame that will protect it from environmental influences.
To make it, you can use a metal box or make a protective screen out of glass. It is also worth installing a casing that covers the end of the disk by a third. It will protect the worker if the abrasive disc cracks.
Photo of sharpening drills with your own hands
Note!
Note!
If you constantly deal with sharpening hard workpieces, the surface of the drill will very quickly become unusable. It will become dull, become very hot and eventually lose its former strength. All this is a consequence of “letting go” of the metal. That is why such a tool needs periodic sharpening using special devices.
How to do 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 household needs. However, if possible, then after they become dull, it is better to sharpen the tools than to buy new ones.
There are factory-made devices designed for sharpening, but buying them will cost you a lot, and this will not make up for the savings from not purchasing new tools. That is why many craftsmen collect machines for sharpening with your own hands.
It is worth noting that dulling applies to metal drills, since wood tools are practically not susceptible to this, except when used at high speeds with resinous workpieces. Also cannot be sharpened pobedit tips for stone or concrete.
But many people sharpen metal drills 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 properly make a tool for sharpening drills with your own hands: training 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 with a special template.
Simple ferrous metal drills 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 immediately several templates depending on the listed values and, in accordance with them, sharpen with your own hands. The same drill can be used for different types workpieces, you just need to change the angles of the top of the workplace.
A simple but very convenient pulling device is bushings different sizes , which are attached to the base. You can make them yourself, based on special drawings. Remember that the tool should not be loose in the sleeve, 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 standard parameters of the drills, or take a block from soft material and make a lot of holes in it. It is very important to place a convenient tool in the sharpener, thanks to which it will be possible to the right angle move the sharpening device and hold the stop.
The listed sharpening devices have been manufactured for many decades in a row and are still in demand. For assembly sharpening machine With your own hands, you can take an oak block instead of a corner.
The simplest sharpening machine can be assembled by simply installing 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
You can find it on the Internet ready-made drawings devices for sharpening drills, or sketch them yourself, but for this you need to 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 off a small distance to re-process it.
After finishing the work, the drill should cool down, also take measurements using 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 the following errors:
How to use improvised means with your own hands assemble a twist drill sharpening machine on metal?
For the basis of the device, you can take any sharpening machine that is capable of working properly, there is no axis runout, and it maintains speed under load.
The task looks like this:
- the tool rest must stand strictly 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 semi-automatically;
- the shape of the tool rest should facilitate the free lowering of the drill shank to the desired angle.
No specific parts are required to make this device; almost everyone has everything they need home handyman. Workpieces are processed Bulgarian, welding or sharpener.
For semi-automatic mode, a swing stop is assumed, so you need to make a loop connection. Choose exactly for no backlash bolt, bracket and tube holes.
The platform must move along the vertical axis so that you can change the sharpening angle of the drill. This axis can be fixed, and the tool rest should swing, while resting on the horizontal axis, which, when sharpening, provides the necessary articulation.
Support plate made of metal 4 mm thick, and the main parts of the structure should have a thickness of 3 mm, respectively. This ensures its high strength. The tool rest is rigidly connected to the emery body. Attach it to protective casing This is not possible, so screw the bracket using the metal “cheek”.
Then we screw the guide plate itself for drills with a thickness of 5 mm to the support plate. In it, to fix the drill during processing, sawing triangular groove.
The design has a rotation angle of 90 degrees, which allows for point different methods . Starting from the Leontiev method and ending with pressing at a certain angle and creating an acute angle of the edge due to the curvature of the sandpaper.
During processing, the drill 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 support plate above the axis of movement of the disk, it is possible to achieve the desired shape sharpening the back edge.
Before performing work, the drill should press against the plate and align the cutting edge parallel to it. The adjustment is now complete and you can bring the tool to the sandpaper. Sharpening must be done slowly and carefully, carefully monitoring the angle.
Thanks to this homemade tool, it is possible to achieve high accuracy sharpening and practically no template is needed. True, it will take time to install the machine and adjust the angle, but then you quickly and easily sharpen drills in the right quantity.
But if you need to sharpen a drill equipped with a carbide attachment, you can attach a swinging plate to a fixed angle. To do this, place several washers under the axle nut.
Using an emery wheel in a homemade sharpening tool
For universal sharpening work, white wheels based on electrocorundum are mainly used. They are used for sharpening shovels, axes, knives and metal workpieces.
For the purpose of processing carbide drills or high-speed metals, you need to take abrasive green wheels based on silicon carbide marked 64C. But for household needs, a wheel grit of 25N is sufficient.
Sharpening drills requires a finer fraction in the area from 8H to 16H. Remember that silicon carbide-based abrasives get very hot during operation, so the drill cannot be kept in contact with such abrasive for a long time. Let the metal cool down after 2-3 approaches and cool it in soda water.
Edge quality depends on direction abrasive rotation. Its working surface must run over the cut (go from top to bottom).
Peripheral emery surface when processing it must be smooth. It can be adjusted with a CBN-based nozzle. If the disk has a small diameter, it is permissible to use pliers in which the CBN cutter will be held.
So, we looked at how at home you can assemble and use devices of varying complexity for sharpening drills and more. Choose suitable option you can depending on your household needs.
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). A top part turn 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 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
This sharpening tool is good for 3 mm 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.