How to sharpen a knife to razor sharpness. Wood carving tools and their sharpening angles How to properly sharpen a semicircular chisel

Materials and assembly rules
Assembling the grinder
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 in the cutting tool.

When working with sandpaper, it is necessary to maintain the sharpening angle, which is not easy to do manually without a special tool. This problem is solved by a wooden device that 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 at various 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 a slitting disc, a bevel is sawn at an angle of 25 °, and the workpiece itself is fixed with 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 drying adhesive composition final assembly is in progress. 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, pay attention: 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 finer abrasive, go over the coarse-grained paper a couple of times with the back of the blade, 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, a wooden blank with a rounded edge is taken, 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.

There is one true rule: a sharp blade is much safer than a dull one. It's right! The rule applies not only to the manufacture of sharp edges of the chisel, but also to other carpentry and even kitchen appliances. Therefore, first of all, it is necessary that the pointed edge of the chisel be regularly cleaned at least a couple of times a year. If the tool is actively used in work, it is necessary to clean it much more often.

First stage

Even a set of brand new chisels that have not yet been used in work cannot be suitable for starting to work with them. Even though they stay sharp for a very long time, you should know how to sharpen a chisel right. After all, the quality of the work performed depends on it.

If the carpentry is a little aged, has a little jagged edges or rust, then you can correct this with a grinding wheel. Carefully hold the bevels of the defective chisel near the grinding wheel to get rid of large scuffs and rust.

To work, you need a three-level sharpening stone - the smallest, beginner and medium, in order to achieve a greater sharpness of the chisel. Sharpening stones can be purchased at hardware or garden stores and are quite commonly used for sharpening kitchen knives. The stone you bought must come with a lubricant, or purchase it separately. Note:

Do not use water lube for oil stones. For them, you need to buy special tools in hardware stores;
Water stones prefer water as a lubricant. They must be soaked in plain water for a few minutes, after which they can be used. This method is quite common in Japan.

Now you need to prepare the stones accordingly. Usually such stones come with instructions. Also, the instructions are written on oil lubricants.

Chisel sharpening

We start sharpening ours from the flat side, it should be so pointed that it will look like a mirror. We begin to intensively move the tool along the grindstone. It is important that when sharpening, your hand is fixed, so the chisel will be sharpened evenly. Do not allow yourself sudden movements: everything should be slow and as smooth as possible.

When the whetstone begins to show minor scratches, go to the fine-grained side, and then to the very fine-grained side. The flat or, as it is also called, the flat side of the tool will be perfectly sharpened when it starts to look like a mirror.
A few tips:

You can not move either a grindstone or a chisel from side to side. We move only in the length of the stone for sharpening.
When working, use the entire surface of the grindstone.
Be sure to clean your hands and chisel from dust, as it will obscure appearance products.

Wood chisel sharpening angle

This can be done manually, but there is a very high chance of making a mistake. To get the perfect angle, place the chisel in the sharpener, tighten the screws to keep the chisel firmly in place. The angle of inclination largely depends on the type of chisel being sharpened:

cleaning the chisel - set at an angle of about 20 degrees;
for a regular chisel, increase the angle by five degrees.

Additional finishes

Usually, after sharpening, the chisel can already be used, but if you want it to be even sharper, then it makes sense to add a microbevel. In fact, this is another small bevel, which is made at the very tip of the chamfer. This is a necessary step when performing very delicate and precise work. To make a micro-bevel, you need to adjust the sharpening machine to work at an angle of 5 degrees. Repeat the work done using a fine-grained stone.

For sampling wood in recesses or for chamfering, as well as for trimming wood, when processing furniture products, a cutting tool called a chisel is used. The main components of a wood chisel are a steel blade and a wooden handle. There are three types of it, these are chisels for wood carving, chisels for turning and carpentry chisels.

Working with a chisel is a very complex and time-consuming process, which consists in pressing the tool with your hand. If additional efforts are needed when chiselling, then you can use a special carpenter's hammer, which is called a mallet. For its manufacture, solid woods are taken. It should be noted that the mallet is used only for chiselling, and if stripping or trimming is performed, only a chisel is used.

The size of the chisel is chosen according to the size of the place that needs to be hollowed out. Working, basically, it is held in the left hand, and in the right, if necessary, they hold a mallet. Work begins with light blows, then, depending on the deepening, the blows should be stronger.

Chisel sharpening.

Sooner or later, the blade of the chisel will become dull and will need to be sharpened. For this, a grindstone or whetstone is used, but these methods are outdated. Now there are a lot various devices with which you can sharpen the blade of the tool.

The size of the sharpened angle of the blade depends on what kind of work the tool will be used for. The smaller the sharpening angle, the sharper the blade, of course, it is easier to work with such a chisel, but its wear also increases significantly. The best option would be when the angle of sharpening the blade is 25 degrees.

If sharpening will be performed on an abrasive machine, then you first need to set the desired angle, and then clamp the blade in the shoe. It is polished from the beveled side, periodically turning the chisel, then to the right, then to the left. When sharpening, the blade will be hot, you can use a special liquid or just cold water to cool it.

It is undesirable to sharpen the blade at a small angle. As a rule, after sharpening, a sharp edge forms on it, it must be sanded. To do this, you can use a grindstone, grinding is done in a circular motion, turning the blade in different directions.

Come visit us at the workshop.

I sharpened like a couple of narrow chisels, like sharp ones, they cut well, but the chamfer, which, in theory, should be flat, always turned out to be semicircular. This, of course, is all trifles and does not affect the quality of work, especially if you do not do wood carving, but use chisels only occasionally when you need to cut out grooves or recesses for hinges and locks. On an electric grinder, this jamb is easy to get rid of, but with manual sharpening it is somewhat tedious.

And when it came to a chisel 4 cm wide, I realized that I needed to make some kind of holder (corner). I didn’t want to bother much with its design, since we use chisels once every five years and we don’t have to sharpen them very often. At first I tried to make it on a loop so that the sharpening angle could be adjusted, but I quickly abandoned this idea, the design turned out to be shaky, and when you set the angle to less than 40 °, the design starts to take up a lot of space.

In general, I assembled a monolithic corner from three pieces of chipboard, a couple of corners and several self-tapping screws. I set the length of the main piece according to the chisel (so that the handle does not rest against the rack).

This piece (platform) is needed so that the handle of the chisel does not interfere when tightening it with a plate.

We drill, countersink and fasten the platform.

As a clamp, I screwed a plate from a window shutter.

Put the rack and marked the holes on it

Before screwing it into place, I sawed off the corners to make it more convenient to hold the corner when sharpening

Reinforced with two long screws.

Tests have shown a slight play with strong pressure on the corner, so that metal corners it is better to install with a stiffener or cut out triangles from the same chipboard, instead of iron corners. Better yet, just cut out a finished monolithic corner in the shape of the letter G from chipboard or plywood, thus getting rid of any joints in the corner, but this will be a completely different design. The dimensions were not particularly calculated, everything was assembled from chipboard cores, but just in case, I drew the dimensions.

In this place (photo below), from the corner on which the corner stands, I cut off a couple of millimeters of PVC edges, since during sharpening such a long contact area slowed down the corner very well, I left only three centimeters from the edges as legs, the best option it would be possible to screw the rollers around the edges, but this will complicate the already complex design. :-)

This is a very old homemade chisel on which I will check the corner, a little killed of course, but the piece of iron itself is good :-)

Everything is assembled and ready to sharpen.

I sharpened it on ordinary sandpaper in three passes, the lightest and the paste is for showing off, but more on that below :-)

Here I made a mistake that increased the work time several times, before sharpening, I slightly aligned the cutting edge with a dremel so that it was even and not a semicircle, but as it turned out, the chisel had slight wear on the opposite side at the corners. This means that to get a smooth edge, I would have to chamfer 5-6 mm. I know that it is supposed to make it smooth, but for myself I decided to make an exception. :-)

This picture shows how easy it is to set the desired sharpening angle, I didn’t get too carried away with geometry, I just put two pieces of chipboard under the chamfer and thereby got the angle that this chisel had before sharpening.

The chamfer is brought to the plane.

The beginning of the formation of a burr, the rounding of the corners of the edge is already visible due to the fact that there is wear on the top corners. Didn't dwell on it.

After the burr has appeared along the entire edge, we switch to paper with a smaller grain, and then to the finest, the more steps, the less paper consumption.

I used this paper as a zero, (it is at the top) I also removed the remnants of the burr on it.

After zeroing, you can already see the reflection almost like in a mirror :-)

Yes, and the paper cuts not bad, though with a little effort and at the same time it must be driven from side to side, the movements are similar to how bread is usually cut.

In principle, such a sharpening is enough for me, but still I decided to try to bring it to the planing of the hair. For show off, I used what was at hand, namely, paper with even finer crumbs and goy paste.

I didn’t find a belt or a piece of leather, I just put the paste on a sheet of paper and polished the bevel on it.

As a result, a mirror was obtained, the paper began to be cut a little easier, sometimes it was even unnecessary to drive it from side to side, but simply feed it onto the blade. The hair cuts badly, I only cut off a few hairs, so it can be said that it does not cut at all. Most likely I’m sharpening incorrectly, but it doesn’t matter, Temka is about a corner for sharpening flat pieces of iron, and each one sharpens in his own way. :-)