A knife sharpening device is a necessary thing in every home. Of course, you can purchase an industrial-made sharpening machine. But you should keep in mind: the scissors that are sold in specialized stores are quite expensive and often fail.
construct a simple sharpening machine with your own hands. This sharpener does not take up much space and is very easy to use. If you don’t want to make something, you can use a regular sharpening stone. However, a knife sharpening machine is still a great idea, because a simple machine will always come in handy, and you can sharpen other tools on it.
Rules
Often, when sharpening knives at home, household members use abrasive whetstones. However, in order to use them in practice, you need the necessary skills and experience working with them. After all, if the knife is sharpened at the wrong angle, the blade remains dull.
Layout of the block to the blade.
Before actually manufacturing the machine, you need to listen to the advice of sharpeners.
When sharpening a knife, the master performs the following actions:
Defines the angle between the working area of the blade and the block. Moreover, for each model the angles are different;
The knife is located at an angle of 90 degrees to the direction of the block. The grooves that are formed when the razor blade of the knife rubs against the block should be at 90 degrees to the knife line. The angle in such a situation is equal to half the sharpening;
Typically the angle is 25 degrees;
The mechanic begins processing from the beginning of the foot blade;
When adjusting the sharpening angle, the master paints over part of the foot blade with any marker. As a result, the mechanic directly controls the work area.
As a rule, after sharpening the working blade has non-uniform deformations. Therefore, when processing independently, the “point of reference” should not be the sharp part of the knife.
Choosing whetstones for sharpening a knife
The main indicator of a block is its grain size.
The whetstone is the main component that makes the blade thin and sharp. As a result, before choosing a design, you need to select the necessary blocks.
When sharpening knives on their own, household members use these types of whetstones
which have a high grain size. Using such bars, the shape of the leg blade is corrected.
having medium grain size. With the help of such bars, the mechanic removes the grooves that are formed during the initial processing of the knife
whetstone, which is covered with GOM paste. In such a situation, the mechanic polishes the blade.
When processing knives for the kitchen, you can use two types - with medium and high grain. And also in this case it is necessary to use a touchstone.
Why do knives get dull?
In some homes, knives remain sharp for a long time, and there is no need for sharpening. And for some owners, on the contrary, they become dull every now and then. Why is this happening? Here are the most common reasons:
- Use ceramic and durable glass cutting boards. These boards are, of course, beautiful, but they do not perform their main function well, and the blades quickly become dull;
- Improper storage. They usually become dull due to corrosion. Corrosion, or rust, occurs if the main kitchen tool is stored in conditions of high humidity;
- Any knife gradually becomes dull as you work. Small particles of food (vegetables, fruits, meat and fish) inevitably fall on the working surface of the blade, and the sharpness of the blade gradually decreases;
- The cutting tool will lose its working properties very quickly if you cut all types of products with one knife. It is not worth doing this for sanitary and hygienic reasons.
Base
When making a sharpening machine at home, you can use various parts. In particular, you can use laminated box plywood 12 mm thick, which was previously used to create radio equipment housings.
When constructing a machine at home, a household member performs the following actions:
Selects a base for such an installation, which must weigh at least 5 kg. Otherwise, it will be impossible to sharpen chopping devices and tools on the machine. Therefore, in the manufacture of such equipment, the tenant uses various steel angles measuring 20x20 mm;
Next, 2 parts are cut out of plywood with a jigsaw, which have a trapezoidal shape, the base is 170 by 60 mm, and the height is 230 mm. When cutting, the mechanic makes an allowance of 0.7 mm for sharpening the ends: they end up straight and fit according to the markings;
Installs 3 parts between the inclined walls on the sides - an inclined surface made of plywood with dimensions of 230 x 150 mm.
In such a situation, the trapezoidal sides are located laterally on a rectangular surface.
The result is a base - a wedge. In such a situation, a protrusion of an inclined surface measuring 40 mm is formed in the front part;
Then, along the side wall ends, the mechanic marks 2 lines with a thicknesser. At the same time, it retreats by half the thickness of the plywood;
Next, he drills 3 holes in the boards to connect the parts of the structure with screws;
Drills the ends of the inclined surface and connects the base parts for a while;
At the back of the structure, the mechanic connects the side walls using a 60x60 mm block, which is attached to the end with two screws on both sides; — makes a 10 mm gap in the block.
In such a situation, it retreats 50 mm from the center - 25 mm from the edge. To maintain a vertical position, first drill with a thin drill from 2 edges, and then expand;
Then, at the top and bottom, two threaded fittings are screwed into the gap, and in the fittings - a 10 mm pin, the length of which is 250 mm.
If the threads do not match the studs, the lower fitting is adjusted.
Application of the machine
The simplest machine for working at home is a motor with an abrasive. The wheels can be diamond, CBN or silicon carbide.
It is difficult to keep the blade in a certain position relative to the abrasive. You need to use the tools. This can be a horizontal stand or a fixing device, where the upper plane must coincide with the axis of the abrasive.
The tooth to be sharpened is located on the plane so as to be perpendicular to the blade. After turning on the engine, the blade is brought to the circle and pressed against it with a tooth. The layer of metal being removed is regulated by the pressing force. Having finished working with one tooth, the next one is approached using the same method. And so on in a circle until the end.
For the purpose of universalization, the stand is being modernized. The front part is made movable, and a pair of bolts are screwed into the rear. With their help you can adjust the tilt of the canvas. It becomes possible to sharpen the front and back planes of an oblique tooth.
The problem of maintaining the same front and rear sharpening angles remains. To do this, it is necessary to fix the blade relative to the center of the abrasive wheel. To do this, the disk is inserted into a special mandrel, and a groove is made in the stand for it. The required sharpening angle is maintained by moving the mandrel along the groove. If the diameter of the disks is different, then it must be possible to move the engine or stand with a groove.
Another way is to install stops that will fix the desired position of the disk.
Tool support device
When making a handhold device, the following steps are performed:
Removes the flat inclined part from the base, modifies it and installs a fixation device on it, as well as the clamp of the device used;
Measures 40 mm from the edge in front and, using a garden hacksaw, uses this mark to cut out a groove, the depth of which is 2 mm;
Using a shoemaker's knife, chip off the top 2 veneer layers from the end of the board. The result is a sample into which the mechanic inserts a 2 mm steel plate at the same level as the general surface;
The tool rest consists of 2 steel strips measuring 170x60 mm and 150x40 mm. The machine operator connects them along the large end, which has equal edge indentations, and makes 3 through slots of 6 mm.
Using bolts, tighten the planks along the cracks made. In such a situation, the machine operator leaves the bolt heads on the side of the large top plate;
Next, using electric arc welding, the bolt heads are baked and welded to the plate;
Then he removes metal defects of the weld in the form of beads and grinds the plate to give it a smooth surface;
Applies a small striker plate to the edge recess, moves the slots with a drill and secures the support with bolts.
Exploitation
Before you start making this unit yourself, you need to think through the drawings of a machine for sharpening circular saws. You can calculate them yourself, or you can turn to a professional. In any case, in order to understand all the intricacies of the future device, you cannot do without a preliminary paper version. If you have the necessary knowledge, you can cope without turning to a specialist.
A machine for sharpening circular saws, created with your own hands, has a big advantage in terms of price over a factory unit. It also does not require any special skills to operate.
Fixation device
The second important part of the tool rest is the clamping bar. It can be made from 2 parts.
L-shaped plank measuring 150x180 mm, the width of the shelves is 50 mm (top);
A rectangle-shaped strike plate measuring 50x100 mm (bottom).
When making a clamping bar, the machine operator performs the following actions:
Places the bottom bar on the far edge of the top bar;
Makes 2 holes in the center and retreats 25 mm from the edges of the part, connects the parts through the holes with two 8 mm bolts;
Screws in 8 mm bolts on 2 sides. In such a situation, the head of the nearest bolt is located near the top bar;
Welds the bolt heads to the plates and grinds them in advance until roundness is formed;
Yes, the inclined board retreats 40 mm from the edge and draws a line with a thicknesser;
Makes one 8 mm 25 mm gap at the bottom and top edges;
Using markings, he connects the edges of the slots and uses a jigsaw to make a cut with an allowance. Use a file to expand the groove to a width of 8.5 mm;
It fastens the planks using a groove that is in the board; the top bolt is tightened with a nut and thus firmly fastens the plank.
Then tightens connection 2 with nut;
When pressing the bottom bar (in the niche of the base), screw a wing nut onto the second bolt.
Carbide sharpener
No wonder they say: “Everything ingenious is simple.” And this homemade knife is a clear confirmation of this.
To make a sharpening device, you will need a metal plate (for example, steel or aluminum), as well as two replaceable carbide inserts from a turning cutter.
Please note: you can use even completely dull plates that are not suitable for work. They can be found in any lathe shop.
The idea of this homemade product was shared by the author of the YouTube channel TOKARKA.
First, we make markings on the metal plate to drill the mounting holes.
We drill two holes, then use a tap to cut the thread. By the way, it is very convenient to use a screwdriver for this.
We clamp the tap of the required size in the screwdriver chuck, and then cut the thread in the drilled hole. It turns out more convenient and faster.
After drilling the holes and tapping them, we attach the carbide inserts to the workpiece using screws.
At the end of the metal strip, you need to make a V-shaped slot between the two cutters.
You can use a hacksaw or a Dremel for this. We remove burrs using a file or sandpaper.
Our homemade sharpener with an adjustable sharpening angle is ready. By turning the carbide inserts, you can adjust the angle between them.
With the help of this universal device, you can not only sharpen a kitchen knife, but also sharpen any cutting or chopping tool that you have at home or in the workshop.
For convenience, a metal strip with carbide plates from a cutter can be attached to the edge of the work table using a clamp.
A step-by-step process for making a simple homemade knife sharpener with your own hands can be seen in the video below.
How to make a knife sharpener from carbide replacement inserts
By the way, the design of a homemade device can be simplified even further - this is for those who do not want to bother with drilling holes and cutting threads.
To do this, replace the metal strip with a wooden block or piece of plywood. In this case, replaceable carbide plates can simply be screwed onto self-tapping screws with washers.
Sharpening angle control
When adjusting the sharpening angle, the mechanic performs the following actions:
Throw a large washer onto the pin, which is located in the block of the machine base, and tighten the nut.
The rod does not rotate in the foot; the block for adjusting the sharpening angle is made from a small carbolite block, the dimensions of which are 20x40x80 mm.
15 mm from the block edge, drill a 20 mm end on both sides, widen the gap to 9 mm, then make a thread inside;
He steps back 50 mm from the axis of the new slot and drills another one in the flat part of the workpiece - 90 degrees to the previous one. Such a slot has a diameter of 14 mm. In such a situation, the mechanic strongly flares the hole using a round rasp;
Screws the block onto the stud - sets the desired height of the eye without using fixing screws;
Secures the block on both sides with M10 hex nuts.
Using replaceable blocks and making a carriage
When making a sharpening carriage, the machine operator performs the following actions:
Welds 30 cm M10 threaded rods with a smooth rod whose thickness is 10 mm;
Uses 2 solid bars 50x80 mm and the thickness is 20 mm. In all blocks, in the center and on top, 20 mm is retreated from the edge, and then a gap is made 10 mm wide;
Screws a wing nut onto the rod, then a large washer and 2 bars, then a nut and washer;
Clamps rectangular sharpening stones between the stones or makes several replaceable sharpening stones.
As a timber base, the machine operator uses a rectangular tube from a profile or a piece of cornice, the width of which is 50 mm;
He sands the flat machine part and cleans it of grease, and glues strips of sandpaper with a grain size of up to 1200 grit using Super Moment glue.
The sandpaper should have a fabric base, and on one of the blocks you need to glue a strip of suede to apply polish to the blades.
