Sharpening a chisel at home: devices and methods. Chisel sharpening technique - choose the right angle How to sharpen a semicircular chisel correctly

When working with a home tool, you should always keep it in perfect condition. This does not require much effort, but otherwise the work will not move much. Before you sharpen the chisel, you need to carefully read the options for this work.

Preparation and work activities

Tools and materials:

• stones;
• chisel;
• water or oil;
• leather;
• paste GOI.

Before starting work, you need to clean the chisel from dirt and rust. Sometimes chips appear on a worn tool, which also need to be leveled with an emery stone. Otherwise, the result of the activity will be very sad.

Sometimes there are situations when it is impossible to manually remove upper layer from metal, which is why you have to resort to the help of an emery wheel, literally cutting off all the particles from the surface. Usually you have to use this method to remove rust and stubborn dirt.

There are 2 types of whetstones that are used in manual and mechanical sharpening, with each of them having 3 levels (fine, medium and large):

1. Water. Before use, they are soaked in a water bath for several minutes. This type is most often used in the countries of the East, except for especially arid ones (Mongolia).
2. Oil. Before you start using them, you need to lubricate the stone with oil. Only synthetic petroleum-based oils are used, which is why Westerners have become adherents of this method.

Now you need to properly sharpen the cutter. To do this, follow the following sequence:

1. Work on the flat side. The movement occurs evenly forward and backward along the same trajectory, after which the result is a mirror image. The movement occurs from the beginning to the very end of the stone, so that the wear is uniform.
2. Now you can turn the chisel over to work with the main part. The cutter moves over a stone with a high grain size without jerks, but quickly enough over the entire surface. It is desirable to observe the angle from 20 to 35 degrees, depending on the desired result. If a chisel is needed for cutting work, then a sharp angle is required, while grinding and trimming do not require such a high sharpness.
3. After the coarse grain becomes redundant (scratches appear), you need to switch to medium, and then, according to the same scheme, to the smallest. Some craftsmen can sharpen their cutter to such an extent that it cuts paper as well as a blade (micron sharpening), but this is only necessary when performing particularly delicate work, so you can get by with just a fine grain.
4. The chamfer is being sharpened. For this, 1.5-2 mm are allocated, which go at a very sharp angle (5-7 degrees), but here the quality should be unquestioning. This chamfer is formed in just a few movements, so it will not take much time.
5. At the very end, you will need a piece of leather (it is optimal to have an old leather belt for this purpose), which is rubbed with GOI paste, after which a freshly sharpened chisel is corrected. The process itself is done with your own hands with fairly quick movements, but without much haste, so as not to cut through the skin.

Proper sharpening of the chisel provides precise cut and ease of instrument control. However, not only the sharpness of its blade is important, but also the sharpening angles, which depend on the type of tool and the characteristics of the work performed. If you properly sharpen the cutting surface and maintain the appropriate bevel angle, then the carpenter will make much less effort when removing chips and easily withstand its thickness. And this directly affects not only the accuracy of the cut, but also labor productivity.

You can sharpen and finish the cutting part of the chisel using both manual and powered abrasive tools. As a rule, these are various grindstones, whetstones wrapped with sandpaper, abrasive sheets, polishing bases made of cloth and felt, as well as vertical and horizontal grinders. In order to sharpen the chisel, first of all, it is necessary to fix it at the desired inclination to the plane of the abrasive. Many do it manually, which, with certain skills, provides more or less acceptable quality. However, most craftsmen sharpen chisels with special tools that fix their blades strictly at a given angle.

The chisel is manual carpentry tool, consisting of a handle and a blade, which in everyday life is also called a blade (see the figure below). Its metal part is made of tool steels, and the handle is made of wood. hard rock: oak, beech, hornbeam, birch, acacia. Recently, modern polymer materials. The cut of wood is carried out by the cutting edge of the chamfer, the sharpening angle of which depends on the type and purpose of the chisel.

Sharpening a chisel on your own is easy if you follow certain rules. Regardless of what and how you are going to sharpen this tool (manually or using an electric grinder), its blade must be rigidly fixed at a given angle, not only in the longitudinal direction, but also in the transverse direction. Chamfer blockages to the right or left are unacceptable, as this causes tool retraction and uneven chip removal.

The chamfer can be sharpened with a grinding stone with a grain size of 300÷400 µm. The main thing at the same time is to achieve its linearity and equality of the angles of inclination in both directions of the canvas. Finishing and sharpening of the cutting edge is carried out on grinding stone grain size 50÷80 microns.

The slope of the chamfer of the chisel blade depends on the type of work for which it is intended. Usually its value lies in the range of 25±5º. This value is standardized by GOST 1184-80, but in practice it may differ slightly in one direction or another. As a rule, the angle at which a chisel blade needs to be sharpened is directly related to its thickness: thicker blades usually have a steeper bevel.

To perform grooving work with a mallet, the chamfer must be sharpened at an angle of 27 ÷ 30º. A steeper slope prevents damage to the cutting edge when applying significant impact forces to the chisel. If you have only one chisel at home, then it is better to sharpen it with a bevel of about 25º - this is suitable for most carpentry work. But for accurate trimming with the removal of thin chips, the tool will have to be sharpened by 20 ÷ 22º. The bevel of the cutting edge with respect to the plane of the chamfer is usually about 5º.

Sharpening accessories

The standard chisel sharpening kit includes three main components: an abrasive for initial processing, grinding materials for finishing and a sharpening mandrel for fixing the angle at which the blade needs to be sharpened. The latter is divided into two types: equipment, with which the cutting edge can be sharpened to abrasive wheel electric sharpener, and manual mandrels for grinding on bars and sheet abrasives.

Hand tools have many options: from home-made wooden devices in which the angle is set with wedges, to factory-made metal products with angle adjustment. All of them are arranged in approximately the same way and consist of two main functional components: a carriage for moving along the surface of the abrasive and an inclined platform with a clamp, which is set at the required angle before sharpening the blade. In order to sharpen the chamfer, use as hand tools, and power tools, but the finishing of the cutting edge is done only manually.

Using a wheel and sandpaper

When forming a chamfer, chisels use various whetstones: both round on an electric grinder, and flat in the form of grinding and grinding stones, as well as sheet emery material on fabric and paper basis. To sharpen the bevel of a chisel on a grinder, you need to make sure that its speed and the grinding wheel installed on it will not cause overheating and release of the metal of the chisel. The spindle speed of the electric grinder should not be higher than 1800÷2000 rpm, and the grindstone should be used viscous, medium soft and with grinding filler (for example, aluminum oxide).

In order to sharpen and finish the chisel blade with high quality, it is necessary to use abrasive products that combine both grinding and polishing qualities. Grinding tools are best suited for this role. water stones. Before starting work, they must be soaked in water, which rises to the surface during sharpening, mixes with abrasive dust and creates a viscous grinding slurry. Sheet fine-grained abrasive material is also well suited for such work. In the process of sharpening, it must be moistened, so it is advisable to use sandpaper on waterproof basis. You can sharpen the chamfer and edge of the chisel with this material by fixing it on a flat surface or by wrapping it around a wooden block.

Having sharpened the chamfer at the desired angle, you can proceed to the finishing operation, during which the cutting edge will be brought to the ultimate sharpness, with working surface all microroughnesses and scratches will be removed, and it will be polished to a mirror finish. In this case, grinding is the result of finishing, since the main goal at this stage is the linear accuracy of the working surfaces.

Finishing and polishing are inherently different operations. The first provides the geometric accuracy of the chamfer plane, and the second - the class of its roughness. Perfect mirror surface it can be littered to the left or right, or have a significant bulge, which, when the chisel moves, will lead it to the side.

There are two ways to sharpen the cutting edge at the finishing stage. Or simply bring the working end of the chamfer to the required sharpness, or form at its end a small bevel a few millimeters wide with an inclination to the chamfer of about 5º. To do this, the main plane is first brought, then the grinding mandrel is set at an angle of 30º, after which grinding continues until the specified bevel width is reached.

The process of sharpening a chisel with your own hands

To sharpen the cutting edge of a chisel with your own hands, a strong grip, care and patience are required, as well as minimum set sharpening and grinding materials. If you need to significantly change the angle of sharpening, it is better to use a grinder first. If there is no such need, then you can sharpen your chisel in the following order:

1. Grind on an abrasive block until there are no visible shells and damage to the chamfer. It is necessary to strictly maintain its inclination not only in the longitudinal, but also in the transverse direction. This can be done both manually and using a homemade jig from several wooden blocks.
2. Check the line of the cutting edge, which must be strictly perpendicular to the blade of the chisel. If this is not the case, straighten it on a sharpening stone, and then re-sand until sharp.
3. Wrap a wooden block with fine-grained sanding paper, fix it with cloves or staples, moisten it with water, and then, carefully pressing the bevel against the abrasive surface, grind it to a shine and extreme sharpness of the edge. If desired, the blade can then be polished on a felt wheel using polishing paste.
4. If it is necessary to sharpen a chisel with a bevel on the edge, then grinding is best done with an emphasis, lifting the blade up by about 5º.
5. After finishing work, carefully wipe the chisel dry.

To properly sharpen a chisel, you need to remember one important thing. technical rule performing grinding and sharpening works: All movements must be performed in one direction only.

In Russian-language articles, the authors almost never focus on sharpening the bevel of the cutting edge. In practice, many really do without this option and use chisels with a straight edge. What do you think about this? What is the best way to sharpen a chisel? Please share your thoughts and experiences in the comments to this article.

1. Materials and assembly rules
2. Assembling the grinder
3. Edit

If you're into carpentry and woodworking, you know how uncomfortable and even dangerous a dull tool can be. It is advisable to have sharp cutters on hand, for sharpening which you can make a special device yourself.

On a grinding machine, with the proper approach, in 10–15 minutes, depending on the hardness of the steel, a sharp tool is obtained. The process may take a little longer if the cutting edge is significantly damaged. After straightening, the chisel will easily cut wood without the risk of damaging the workpiece or, even worse, injury.

Advantages of a homemade sharpener

On sale there are devices designed for sharpening chisels and planer knives. They differ in type and material of manufacture. These can be synthetic or diamond whetstones, natural minerals and other mechanical items. For carpentry workshops often acquire special electrical machines vertical or horizontal design. However, sandpaper is in no way inferior to all these advertised devices. It does an excellent job of grinding metal, giving it thin and clear edges, and its cost is extremely low.

Materials and assembly rules

An excellent result is guaranteed by black sandpaper, the abrasive side of which consists of silicon carbide. It is suitable for wet and dry grinding, and due to the hardness of the material, which is superior in similar parameters to garnet or aluminum oxide, it copes with the task better and wears out longer.

Sharpening a chisel at home requires sheets of paper with different grain sizes (from 100 to 600 units). The final grinding of the cutting edges is carried out with an abrasive powder with a fine fraction, which can be replaced with a kitchen cleaner containing feldspar, soda or oxalic acid.

To ensure comfortable work on sharpening a tool for woodcarving, the craftsman needs to create an even base of thick plywood or MDFon which sheets of emery will be laid. To increase the adhesion between the paper and the smooth base, you can spray the plywood with water.

No matter how sharp the vision of the master, without the help of a magnifying glass, it is difficult to complete the work. Therefore, it is better to play it safe and purchase a simple lens with an eightfold magnification. Such an optical device does not obscure the light and makes it possible to see most of the flaws. cutting tool.

When working with sandpaper, it is necessary to maintain the sharpening angle, which is not easy to do manually without special device. This problem is solved wooden device which provides control over the process at all its stages. With it, the blade will be fixed at a given angle, deviations are excluded. In this case, the chamfer of the product will acquire an optimal plane. Thus, it is possible to ensure uniform abrasion of the emery when performing movements in opposite directions.

Assembling the grinder

Below in the picture you can see a fixture on which carpentry chisels and planer blades with a length of 75 mm or more with an angle of 25 ° are sharpened. Such drawings are also suitable for assembling a similar machine for straightening blades under different angles. Sharpening of semicircular chisels is carried out on other equipment.

The beginning of the assembly involves sawing out the solid wood base with a margin of length. We recommend focusing on the dimensions of the workpiece approximately 13x76x255 mm. At a distance of 19 mm from the back of the workpiece, it is necessary to cut out a tongue (5x45 mm - GxW), for which a groove forming cutter is installed in the saw unit. Then using the disc slitting a bevel is sawn at an angle of 25 °, and the workpiece itself is fixed double sided tape to the bearing surface. Now, with a vertical cut, the finishing length of the product is 190 mm.

To make a trolley holder, you will need a blank measuring 19x45x255 mm, on which a bevel is sawn off at an angle of 25 ° and cut vertically to a length of 190 mm. Then, from its lower side, at a distance of 32 mm from each edge, two holes are drilled with a recess for the nut. After that, a recess 102x1.5 mm (WxD) is made with a groove disk, in which a chisel or chisel will be fixed at a right angle.

At the next stage, the clamp is cut out and holes for the screws are made in the middle of the workpiece at a distance of 32 mm from each edge. The handle of the device is glued to the clamp, and after the adhesive has dried, the final assembly is carried out. So that the sharpening machine can function normally, and the holder slides effortlessly, a special wax composition is applied to the base tongue.

The process of sharpening on a homemade machine

To sharpen a dull tool, you need to put the device on sandpaper with a large grain. The cutting part of the chisel is installed in the holder under the clamping mechanism with the chamfer down, after which the nuts are tightened to tightly fix the tool. The blade must be perpendicular to the work plane.

Starting to sharpen the cutter, please note: characteristic traces will be visible on the emery, so you need to shift the structure so as to continue the process on the untouched part of the material. Work is carried out until the cutting segment acquires a uniform matte surface. Before changing the emery to a smaller abrasive, walk a couple of times reverse side blades on coarse paper, removing possible burrs. Each time you change the abrasive, repeat the process until the sharpened tool is optimally sharp.

Edit

The sharpening of the chisel is completed by editing with a leather belt rubbed with GOI paste. The cutting edge is polished to a mirror finish. Pasta can be replaced with a kitchen cleaner that does the job just as well as pasta. The powder is poured onto a flat wooden surface. Useful here manual machine, which need to be sharpened according to the previously discussed principle.

Device for sharpening semicircular chisels

Sharpening a semicircular chisel is performed on a wooden block with an edge machined according to the shape of the tool. In the process of work you will need:

• silicon bar;
• plywood;
• abrasive powder;
• leather;
• sandpaper of different grits (400, 800, 1000, 2000).

You need to start the process by wetting the bar in a soapy solution, and then you can get to work by pressing the chamfer to the donkey and moving to the sides (as in the photo below).

After the formation of a burr, take wooden blank with a rounded edge, on which sandpaper is glued (replace it, gradually moving from coarse to fine abrasive).

At the final stage, the chisel is polished and corrected with the help of leather. When the blade acquires a smooth sharp edge, it is necessary to check its cutting ability.

This article is about sharpening chisels for woodcarving. Many novice carvers are interested in the question of how to properly sharpen a tool. Usually chisels and knives are sold prepared for work, sharpened and tucked. For example, Tatyanka's tool is supplied in this form. About that, read here.
But in the process of work, one has to deal with blunting of the cutting edge and even with chips. Chips occur as a result of incorrect movement of the tool when a novice cutter tries to pick up (break out) undercut material. So I got 2 chisels Tatyanka No. 6 in my hands. On one, slightly noticeable chips of the edge appeared, which, however, significantly interfered with the carving, the chisel tore the wood. They tried to sharpen the second one on a bar for knives; as a result, it became unsuitable for woodcarving. I collected examples of defects on the Tatyanka instrument and methods for their correction in album of the group Vkontakte.
I use manual method sharpening, because it is easy to use, and the materials for it are available. The Internet has a large number of sharpening video grinding machines, however, without experience, there is a big risk of spoiling the instrument, so we will leave this option to professionals. For sharpening we need:

1. sharpening block
2. Sandpaper No. 80, 280, 600 (waterproof)
3. Leather straightening belt

So let's go. I use a sharpening stone for rough processing when leveling the chipped surface of the tool. Alternatively, you can take a grinding wheel and grind off excess metal there. The most important thing is not to overheat the tool, otherwise tempering will occur (a change in the structure of the metal, which will affect its rigidity). This is achieved by periodically lowering the instrument into the water. Also, an electric grinder can be used for primary sharpening of the tool, for removing the initial chamfer.

Then put the sandpaper on the sharpening block. We put the tip of the chisel on paper. By adjusting the rise of the end of the chisel, we set the future angle of sharpening the tool, approximately 20-25º. Sandpaper is best to use waterproof, wet it when sharpening. In my case, the #60 cloth sandpaper is not waterproof, so it will clog quickly when sharpened. We begin to drive the chisel along the bar, you can press it with your left hand. The question arises, how to sharpen a chisel if it has a semicircular profile? It is necessary to mentally divide the cutting edge into several equal planes and sharpen evenly in each plane. After sharpening on coarse sandpaper (No. 60), go to No. 280. This sandpaper is paper based and waterproof, so I wet it with water. Sharpening on wet paper is more pleasant and easier. On this sandpaper, you can make rotational movements, i.e. try to sharpen all the edges in one pass. In this case, do not forget about the angle of sharpening. Let's go to the most small paper No. 600. We finally bring the cutting edge of the chisel. I check the quality of sharpening on a tree, if the cut is clean, then you can proceed to the final stage - editing (refueling) the tool.

Editing is carried out on a leather belt lubricated with GOI paste. This stage is described in more detail in the article on. In short, this stage is needed in order to eliminate microroughness on cutting edge, because when sharpening, the edge is a saw, where the teeth are determined by the grain size of the abrasive. We also need the chisel not to saw, but to cut. If the chisel sits down, starts to cut worse, then it is necessary to refuel it again. You can also edit the tool on a felt wheel with GOI paste installed on an electric drive.

The chisel is ready. All the best in carving!

This article is devoted to the actual process for any carver - sharpening the cutting tool. In a previous article, I talked about sharpening flat chisels, but here we’ll look at how to properly sharpen semicircular chisels.

The only difficulty in sharpening semicircular chisels or special ones is their shape. This shortcoming can be corrected by doing wooden blocks, the edge of which we plan in the shape of our chisel. Any tree will do, you can protect it from moisture by wrapping it with tape. Ideally, each shaped chisel needs its own individual bar, so as not to get confused, you can mark it with numbers.

For the lesson we need:

• Double-sided bar of silicon oxide.
• Plywood
• shaped bar
• Powder abrasive
• Sandpaper with abrasive grade R-400, R-800, R-1000, R-2000, I use sandpaper from auto stores.
• soap solution
• Paste GOI

So, let's begin. Wet our bar soapy water, let it soak and start sharpening. We press the chamfer to the abrasive and begin to make movements as shown in the figure.

As a burr is formed, we turn our chisel over, and take a shaped block, cut sandpaper for it, you can glue it, or you can simply press it with your hand. I note that the lower the abrasive gradation number, the coarser it is: That is, R-400 will be coarser than R-800, etc. I think that a separate article will be devoted to the abrasive.

By changing the abrasive, starting from coarse to fine, and not forgetting at the end about polishing and straightening the chisel, we achieve it razor sharp. Check the cleanliness of the cut.

Our lesson has come to an end. Wish you creative success and always sharp chisels.