How to sharpen a drill with a grinder for metal
How to sharpen different drills?
According to experts, one should start an independent practice of sharpening drills with cutting products with a diameter of more than 10 mm. The sharpening angle for such elements is 120 degrees. After the procedure, the front of the drill should be symmetrical. If an error occurs during sharpening, it can be corrected immediately.
At some distance from the cutting edge, there is a so-called flank surface. It should be located within 1-1.5 mm relative to the cutting edge in the downward direction.
Further, it is proposed to familiarize yourself in more detail with the theoretical side of the do-it-yourself sharpening process. First of all, you need to do some preparation. On the surface of the grindstone, draw a line parallel to the rotation of the axis with a black felt-tip pen.
Next, you need to place the drill correctly. It must be kept clearly horizontally. In this case, the markings made with a felt-tip pen will be located slightly above the axis of rotation. Thus, the longitudinal part of the tool, located horizontally, will be turned to the left by approximately 30 degrees, which will ensure that the required sharpening angle is obtained.
Now you can move from theory to practice. A drill with a blunt tip is taken. Next, you need to find the correct position of the tool. Initially, one side is sharpened, and then the other. In no case should you be in a hurry. The work must proceed with the utmost care. If suddenly the sharpened edge heats up and turns red, you need to dip the drill into a container of water. After cooling the cutting element, you can continue working.
Having finished sharpening the knocked-down drill, you need to check the result. For this, a drill is taken, a sharpened tool is inserted into the chuck. Then you can try to drill a steel surface that is 8 mm thick. If the holes are drilled without difficulty, then the sharpening process was correct.
In fact, there are many ways to sharpen cutting elements. And each separate method assumes processing of drills for different materials. For aluminum, copper and even stainless steel, twist drills are used, which are sharpened according to the universal and double “method”. Sharpening a drill for spot welding is done with a grinder. Small drills with a diameter of less than 4 mm are sharpened exclusively by hand. By the way, if necessary, you can independently sharpen the old drill under the milling cutter.
Unfortunately, not everyone succeeds in sharpening a dull drill the first time with their own hands. But with a little patience, you will be able to achieve a positive result.
All about sharpening drills
- Basic Rules
- Sharpening angle
- Tool requirements
- How to sharpen different drills?
Construction professionals constantly deal with different types of drills that become dull over time. Poor quality cutting elements become unusable after a few months. Expensive branded samples serve their owners for more than a dozen years. And it is their builders who do not want to lose, but send them to sharpen. In principle, this is the right decision, however, you have to pay a lot of money to restore the state of a blunt drill. And in order not to empty your wallet, you can use the recommendations for sharpening yourself.
First you need to familiarize yourself with the conical sharpening method. The cutting element is required to be inserted into the prism of the grinder, which moves around its axis. Next, configure the parameters. The axis of the taper should have an angle of 45 degrees to the axis of the drill. It remains only to activate the device and wait until the end of the work. The tapered method is used to create a sharp increase in the clearance angle of the cutting element.
To automate the process, it is recommended to use the screw method. It is characterized by forward movements consistent with the rotation of the grinding wheel. Remarkably, this method allows you to simultaneously sharpen the front and rear corners of the cutting element.
In the modern market, you can find twist drills, flat and center models:
- spiral elements, according to their name, differ in the spiral shape of the edges;
- flat products are designed for making deep holes of large diameters;
- center drills are used to center elements.
All the presented types of drills become dull over time. Reducing the sharpness of the cutting element interferes with construction work. This means that the product needs to be restored.
To date, 5 types of drill sharpening have been developed. Each individual method corresponds to the type of material of the cutting element and the specifics of its work.
- “H”. this type of sharpening is universal. However, it is used when restoring drills with a maximum diameter of 12 mm.
- “NP”. in this case, sharpening of short crossbars is performed.
- “NPL”. a type of sharpening involves lengthening the transverse edge and width of the tape.
- “DP”. in the professional field, this type of sharpening is called “double”. In addition to the transverse edge, 4 more edges are formed in the form of broken lines.
- “DPL”. the description is similar to the 4th sharpening method, only the sharpening of the tape is added.
Those who use the drill once a year do not notice that it loses its sharpness. But with this approach, at one point, it simply will not make a hole. And then you will have to make an independent decision. either purchase a new drill, or restore a blunt.
The very process of sharpening on professional equipment does not require human effort, which cannot be said about restoring sharpness with your own hands. However, before proceeding with a detailed acquaintance with the rules of sharpening and the intricacies of the process, it is necessary to find out the signs that the drill will soon become unusable:
- the cutting element is very hot;
- small metal shavings fly out from under the edge;
- the noise from the working drill becomes many times stronger.
Particular attention should be paid to the last feature. The friction between the blunt edge of twist drills and the surface to be drilled increases, resulting in unusually loud noise. In such a situation, it is necessary to immediately stop working, otherwise the cutting element will heat up, its structure will change, so it simply will not be possible to restore the drill.
Further, it is proposed to get acquainted with some of the rules and instructions of experienced craftsmen who are engaged in regular sharpening of blunt centering tips.
And what is remarkable, from the information offered, it becomes clear that you can restore the drill with your own hands.
Drill sharpening process requires special equipment. In this case, we are talking about grinding machines and attachments for drills and hammer drills. A sharpening machine is a device equipped with a sharpening stone. Drill and hammer drill bits have unusual tip shapes. Often in private houses there is a miniature sharpening machine, since this device can be used to sharpen not only drills.
The sharpening technology depends on the type of drill. Today, there are conical, screw, cylindrical, single-plane and double-plane cutting elements on sale. Each of the presented types of cutting elements requires a special approach to sharpening, however, the common thing between them is that only the rear edges are sharpened.
It is very difficult to do it manually, but it is possible. Especially when it comes to small specimens. Small and thin drills are always sharpened by hand, thanks to which a person fills his hand in the sharpening skill and after a while can put in order cutting elements of large sizes.
Single-plane drills differ from their counterparts by the presence of only one plane. The angle of inclination of the sharpness according to the standard ranges from 28-30 degrees. It is this part that lends itself to restoration. This beveled plane is brought up to an inactive grindstone. If the stone rotates, chances are high that the drill will get the wrong angle. Two-plane drills are sharpened in a similar way. The only difference in the sharpening process is the need to process two planes.
It is important to be very careful when restoring tapered drills. The tapered shape of the edge must not be disturbed. That is why the drill needs to be brought to a rotating grindstone, press on the cutting element and sharpen the cone with oscillatory movements. The main thing is not to remove the drill from the stone and carry out the entire procedure with one touch.
An important rule of thumb when sharpening drills is to maintain the shape of the edge. It is no secret that this is not possible in every case. Especially when it comes to sharpening drills with a diameter of 10 mm or less. However, for this type of cutting element, it is preferable to maintain only the clearance angle.
As for drills with a diameter of more than 10 mm, grinding professionals advise to sharpen not only the edges of the planes, taking into account the angle holding, but also the front planes, which significantly improves the technical characteristics of the structure. This sharpening will be more effective in drilling work.
Due to the correct sharpening of the rake plane, the angle of the cutting part of the drill becomes larger, which significantly increases the endurance of the metal element. In addition, the transverse length of the edge becomes smaller, due to which the product does not cut the hole, but scrapes.
After the sharpening procedure, it is necessary to fine-tune it. In simple terms, remove the burrs caused by the mechanical action of the grindstone. For factory sharpening, this procedure is extremely important. Thus, it is possible to increase the level of wear resistance of the cutting element. At home, fine-tuning is not always possible to do, however, if there are the necessary devices, you cannot skip this procedure.
For home finishing, it is necessary to use a silicon carbide or elbor stone. They can be purchased in any construction market. Silicon carbide stone is green in color. Ideally, you should use a copy of grade 63C with a grit index of 6 and a hardness of M3-CM1. If the choice fell on a stone from Elbor, it is necessary to take a specimen with a grain index in the range of 6-8. It is important to pay attention that the presented stones for finishing should be made on a bakelite bond.
Special attention should be paid to step drills. They can be purchased on the market as individual items or as a kit. The diameter of the produced step drills ranges from 4 to 21 mm. Step drills are of high quality and wear resistance, but even these cutting element patterns become dull. And, unfortunately, the restoration of the tip of the drill is possible only in some models.
If we are talking about a victorious drill, use a diamond wheel for sharpening.
First of all, you need to remember that this work process is very complex. The first time no one can sharpen a wood drill correctly. To start self-restoration of such a cutting element, you should practice on a worn out instrument.
The main difficulty of the work is that even one wrong movement can lead to damage to the drill. That is why it is necessary to clearly follow the prescribed instructions:
- a container with water should be placed next to the workplace;
- it is important to get an angle of 45 degrees;
- drills must be held at the edge of the disc;
- for the sharpening process to go smoothly, you need to place the cutting element in the washer;
- the edges need to be slightly tucked a couple of millimeters and monitor their evenness;
- when the sharpening process approaches its logical conclusion, it is necessary to slow down the machine speed;
- at the end of the work, it is required to cool the cutting element and check its performance.
As mentioned earlier, before you start sharpening the drill, you need to calculate the correct angle for the restoration of the cutting element. For the convenience of finding the correct indicator, a special table has been developed, where in the 1st column the degree of inclination with a digital value is indicated, and in the 2nd. the material intended for drilling.
Sharpen Drill Bits on Grinder Fast and Easy – With My Tips, Advice
Steel, cast iron, bronze
An incorrect turning angle will cause the drill and the power tool to heat up during operation. And the quality of the hole to be drilled decreases significantly.
In an industrial environment, sharpening is carried out on specialized equipment in compliance with safety regulations. However, for domestic purposes, several other devices have been invented and developed:
- a mechanism equipped with a sharpening stone;
- machine connected to the mains;
- grinder and drill (however, they are used only in the absence of strict requirements for the sharpening angle);
- sharpening tips for drills.
Each individual device offers a high level of performance, angle accuracy and ease of use. They have a very convenient control system that even an amateur can handle. Another additional advantage of the presented options for home devices is their low cost and miniature size.
Ideally, you need to sharpen the drills with a grinder. However, in the absence of this equipment, you can only use the disc from it. The main thing is that the grain size of the emery wheel meets the requirements. The round emery should be secured to a drill or sander. It is recommended to use a grinder only as a last resort.
It is important to note that there are multiple health risks associated with sharpening cutting elements. Therefore, before starting work, you should protect your eyes by wearing special glasses. A bowl of cool water should be placed next to the drill to be sharpened, in which the cutting element will be cooled.
How to sharpen a drill for metal and concrete with your own hands
It does not require special proof 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.
It remains only to 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 conventional 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.
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. In this case, the posterior angle ranges from 28-30 °. The drill is simply attached to the circle, so that the cutting part goes 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.
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 to the grinding wheel.
We swing the drill down, 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 angles. 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
What is the point of undermining? By reducing the rake angle and increasing the angle of the cutting edge, the resistance to chipping increases, which increases the resource of the drill. In addition, the width of the transverse edge becomes smaller. The transverse edge does not drill, but scrapes the metal in the central part 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. At the same time, the drill rubs less than the back surface in the drilling hole. Cm.
In production conditions, after sharpening, as a rule, finishing is done, which smoothes the surface, removing small notches. The drill, on which the finishing is done, wears out less than just a sharpened drill. If possible, debugging 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.
Below we present to your attention an excellent selection of training videos by watching which you can definitely sharpen your drills.
3 main rules
Before starting work, you should familiarize yourself with the structure of the drill. The tool consists of a shank and a working part, at the end of which there are elements involved in cutting metal or other material:
- two cutting edges,
- flank surfaces (areas behind cutting edges),
A sharpened drill looks like this:
- Two cutting edges are sharp and symmetrical to each other.
- The flanks are chamfered and located below the cutting edge. That is, there is a gap between the part to be drilled and the tool tip.
- The jumper is not too thick and is in the center.
In order to sharpen the drills properly, it is important to have good lighting in the room. A person must have good eyesight. If your vision is low or the instrument is shallow, you will need a magnifier (glasses with magnification).
Determination of angle and shape
The main task when sharpening a drill is to restore the factory shape. Drills are flat, spiral, center, with one or more edges. Some are designed for wood, others for plastic, metal, copper, etc. According to the purpose of the cutting part, the correct shape is given.
The most popular is the twist drill for metal. It is used for drilling wood, metal of medium and low hardness, plastic. When sharpening such a tool, the apex angle of 118 degrees is maintained (if necessary, it can be changed by 30% up or down). Front angle is 20 degrees, rear angle is 10 degrees.
Stages of work
According to the rules, you need to sharpen in a utility room, in a garage or, in extreme cases, on a balcony. Under no circumstances should you do work in the kitchen. Metal shavings and dust will fly around the workplace. It is impossible for it to get into the eyes, digestive organs, respiratory tract. You should wear glasses, and after the end of sharpening, vacuum the room and do wet cleaning.
Drill sharpening consists of several stages:
- Grinding tool preparation.
- Determining the exact angle and method of sharpening.
- Sharpening. First, the rear surface of the drill is grinded, then the cutting edge is straightened and the bridge is reduced (if necessary).
- Lapping to smoothness.
When sharpening, make sure that the drill does not overheat. Otherwise, the risk of deformation increases. Place a container of machine oil (or, in extreme cases, water) next to it. After drilling each point, immerse the drill in the liquid for 2-3 minutes.
You need to use the grinder only in extreme cases. It can cause injury if it is mobile. In order to avoid unpleasant situations, it is recommended that the tool be securely fixed on a plywood sheet or inserted into a vice. Also, amateurs make special devices for guiding and holding drills at a certain angle. They are attached to the grinder. The result is a convenient and efficient sharpening machine.
For sharpening, an abrasive wheel is installed on the grinder. The further course of work is exactly the same as when using a grinding machine:
- The drill is set at the desired angle to the abrasive disc.
- The back surface of one tooth is grinded, then the second.
- The length of the cutting edges is corrected.
- The jumper is being sharpened.
The grinder can only sharpen thin drills. Sharpening large diameter solid tools is likely to cause injury.
How to sharpen drills correctly. 3 easy ways
With constant use, the drills last 2-3 weeks. Considering that many of them are expensive, and it is not easy to find a good sharpener, many try to restore them on their own. How to sharpen drills? There are many different ways to sharpen. We will tell you about the simplest ones, which do not require expensive electrical equipment.
How to Hand Sharpen a Twist Drill
Conical and single-plane sharpening
These are the two most common ways to create a back apex angle.
- A conical clearance angle is formed in drills of large diameter. from 3 mm and above. To do this, hold the product with two hands, press it against a grindstone on emery and gently shake it with equal pressure. Similarly, two teeth are sharpened.
- The single-plane clearance is suitable for small drills 1–3 mm in diameter. The teeth are ground in one plane parallel to the emery. In this case, the slope can be 28-30 degrees.
Grinding machines for drills are used in carpentry workshops. Professional equipment is accurate and allows you to quickly restore the cutting ability. However, the cost of good machines is quite high. 90-200 thousand rubles.
At home, instead of sharpening machines, they use a grinder, emery or a special nozzle for a drill. All three methods are relatively easy and allow you to sharpen twist drills in a few minutes.
Experienced craftsmen are able to maintain the desired sharpening angle “by eye”. It is difficult for beginners to do this. they are advised to make a special device from improvised items. For example, from a suitable sized bolt, nut and powerful magnet, metal corners, a wooden block:
At a minimum, you should draw a line at the desired angle on the emery handguard (in extreme cases, the table). Use a protractor.
To make a machine for sharpening drills with your own hands, you need to make an effort. Shop counters are expensive (from 50). At home, they are made literally from trash.
The stand consists of 5 parts:
- Emphasis. The drill rests on it.
- Tightening nut with goniometer. You just need to immediately set the emphasis in the position at which inclination to sharpen drills for metal.
- Clamp for tooling. In order not to hold it with your hand and get rid of accidental cranking.
- Boat. Allows you to move the rig.
For personal use, you can donate a carriage and angle measurer. Here is a detailed drawing of the drill sharpener.
Adaptation for engraver and electric drill
An elementary device for sharpening a drill, which is very simple to make, since it consists of only 2 parts:
- Housing. It is usually solid and made of plastic. It has a ring that locks onto the engraver’s collet and a 60-degree bushing. The drill enters there with a stop, so there is no displacement.
- Small grinding wheel. He grinds off some of the metal.
In everyday life, the body is made of a steel profile pipe. The holes are marked so that their direction is 60 degrees, relative to the longitudinal axis.
If there is no engraver, there are devices for sharpening drills for metal on a drill. For them you will need:
- Round tube 50 millimeters. Even a plastic plumbing pipe and a plug for it will do.
- Grinding cone or 60 ° tilt cutter.
In the plug, you need to drill a nozzle around the circumference.
How the herringbone is sharpened
In fact, the sharpening of a step drill for metal is similar to a standard one. It has the same slope, the only difference is in the form.
In this case, it is better to watch the lesson.
An elementary tool for sharpening is a grinder and a grinding disc. Regular cutoffs will not work. they are too thin. Since the load is lateral, the disc may burst. Considering that the protection will be from below, the fragments will fly directly into the face or body. Otherwise, you can sharpen a drill with a grinder quickly and without the skills of a locksmith.
To properly sharpen drills for metal, follow the instructions:
- The shank is clamped in a clamp or vise. It will be easier if you immediately set the slope of 120 degrees so that the grinder displays a flat plane.
- The grinder must be kept parallel to the floor and gradually remove the metal from the edge.
Every few passes, the edge is “tested” with a fingernail. If it is cut, it means that the drill turned out to be sharpened.
It should be borne in mind that the fast cutter from which the consumables are made is very moody. You cannot overheat it, so you should not get carried away with a grinder. Water the edge with cold water regularly and work no longer than 3 seconds.
Now it’s time to make a drill sharpener. It will suit 2 types of craftsmen:
Beginners who are unable to keep an even tilt. As a result, the edge is uneven and the drilling efficiency is reduced. Sometimes the drill starts to work even worse than before, and this reduces the speed of work. The adaptations will be useful for craftsmen who have to constantly sit at emery. In these cases, homemade drill sharpeners are a must.
Blacksmithing – very simple way I sharpen metal drills (bits)
How to sharpen a drill with your own hands at home
Many people don’t realize that the drill is a long-lived consumable. But not everyone knows how to sharpen them correctly, although there is nothing complicated about it. If you need to sharpen a drill for metal with your own hands, here are the devices that facilitate this process.
This is already a special tool for sharpening, so it is easier to work with it. To work with steels HSS and P6M5, medium speed is required.
So, the sharpening machine can be prepared. On the “table” near the circle, you can measure 60 degrees in advance in order to orient to it. Put a glass of water next to it and periodically dip a drill there.
Now you can start:
- The drill is set at the mark of 60 degrees.
- Now, without moving the center, you need to carefully rotate it along the axis. With the left hand we hold the spiral near the edge, and with the right hand we turn the shank.
- Every 15 seconds, dipping into a glass of oil, you need to remove the blunt edge.
You can make exultation with a slope of 120 ° in advance. to compare. This will make it easier to sharpen drills for metal.
In this picture you can clearly see the degree.
Based on nuts
A specific homemade tool for sharpening drills with your own hands, which is still suitable for beginners. Here you need a welding machine, since the monolithic body is more durable.
To make a sharpening tool, follow the plan:
- You will need a nut with a large diameter, for example, M 16. It is necessary to cut a triangular hole in it. You need to try to get to 120 degrees. To check this, it is enough to attach the drill with the tip.
- Another nut with a smaller diameter is welded on top. You will need it to screw in the clamping bolt.
- It remains to screw in the bolt and you’re done. The nut will be a guide and sharpening the drills with your own hands will be much easier.
Everyone can assemble such a machine for sharpening drills with their own hands, but its effectiveness is questionable. It is not worth pinning high hopes, as the nut will also gradually wear off.
In fact, these do-it-yourself drill sharpeners are disposable and will not last long. Therefore, they can be collected for training.