How to make a large hole in metal? How to drill Kalenny Steel at home hole in metal with your own hands

Work on the drilling of holes in the metal, depending on the type of holes and properties of the metal, can be performed by a different tool and using various techniques. About drilling methods, tools, as well as safety techniques When performing these works, we want to tell you.

The drilling of the holes in the metal may be needed when repairing engineering systems, household appliances, car, creating structures from sheet and profile steel, designing aluminum and copper crafts, in the manufacture of boards for radio equipment and in many other cases. It is important to understand which tool is needed for each type of work so that the holes are the desired diameter and in a strictly intended place, and what safety measures will help to avoid injury.

Tools, fixtures, drills

The main tools for drilling are manual and electric drills, as well as, if possible, drilling machines. The working body of these mechanisms is drill - may have a different form.

Distinguish drills:

• spiral (most common);
• screw;
• crowns;
• conical;
• pern, etc.

Production rolled various designs is normalized by numerous gtales. Twisted to Ø 2 mm are not labeled, to Ø 3 mm - on the shank it is indicated by a cross section and steel grade, large diameters may contain additional information. To obtain a hole of a certain diameter, you need to take a drill for several tenth millimeters less. The better the drill is sharpened, the smaller the difference between these diameters.

Rolls differ not only with a diameter, but also length - short, extended and long. Important information is the limiting hardness of the cultivated metal. The shank rolled can be cylindrical and conical, which should be borne in mind when selecting a drilling cartridge or transition sleeve.

1. Drill with a cylindrical shank. 2. Drill with a conical shank. 3. Drill with switches for thread. 4. Center drill. 5. Drill with two diameters. 6. Centering drill. 7. Conical drill. 8. Conical multistage drill

Some works and materials require a special sharpening. The stringently the metal processed, the sharper the edge should be sharpened. For a thin metal, the usual spiral drill may not come up, you will need a tool with a special sharpening. Detailed recommendations for various types of rolling and processed metals (thickness, hardness, type of hole) are quite extensive, and we will not consider them in this article.

Different types of drill sharpening. 1. For rigid steel. 2. For stainless steel. 3. For copper and copper alloys. 4. For aluminum and aluminum alloys. 5. For cast iron. 6. Bakelit.

1. Standard sharpening. 2. Free sharpening. 3. Diluted sharpening. 4. Heavy sharpening. 5. Separate sharpening

To secure parts before drilling, vice, stops, conductors, corners, bolts, and other devices are used. This is not only a safety requirement, it is actually more convenient, and the holes are obtained better.

To remove the champers and processing the channel surface, use the cylindrical or conical shape, and for the point of the point under drilling and the drill "not jumped" - the hammer and kerner.

Tip! The best swells are still considered to be issued in the USSR - the exact following GOST according to the geometry and composition of the metal. Good and German Ruko with titanium spraying, and also rolled from Bosch - proven quality. Good products about Haisser products are powerful, as a rule, large diameter. A dignity showed themselves the bison, especially the Cobalt series.

Drilling modes

It is very important to securely fix and send the drill, as well as select cutting mode.

When performing holes in the metal drilling, important factors are the number of drill speeds and feed force attached to the drill, directed by its axis, ensuring the drill tolerance at one turn (mm / O). When working with various metals and swells, various cutting modes are recommended, and the more hard-processed metal and the larger the diameter of the drill, the smaller the recommended cutting speed. The correct mode indicator is beautiful, long chips.

Take advantage of the tables to choose the right mode and do not fasten the drill prematurely.

Feed S 0, mm / about	Diameter of drill d, mm
	2,5	4	6	8	10	12	146	20	25	32
	Cutting speed V, m / min
When drilling steel
0,06	17	22	26	30	33	42	—	—	—	—
0,10	—	17	20	23	26	28	32	38	40	44
0,15	—	—	18	20	22	24	27	30	33	35
0,20	—	—	15	17	18	20	23	25	27	30
0,30	—	—	—	14	16	17	19	21	23	25
0,40	—	—	—	—	—	14	16	18	19	21
0,60	—	—	—	—	—	—	—	14	15	11
When drilling cast iron
0,06	18	22	25	27	29	30	32	33	34	35
0,10	—	18	20	22	23	24	26	27	28	30
0,15	—	15	17	18	19	20	22	23	25	26
0,20	—	—	15	16	17	18	19	20	21	22
0,30	—	—	13	14	15	16	17	18	19	19
0,40	—	—	—	—	14	14	15	16	16	17
0,60	—	—	—	—	—	—	13	14	15	15
0,80	—	—	—	—	—	—	—	—	—	13
When drilling aluminum alloys
0,06	75	—	—	—	—	—	—	—	—	—
0,10	53	70	81	92	100	—	—	—	—	—
0,15	39	53	62	69	75	81	90	—	—	—
0,20	—	43	50	56	62	67	74	82	-	-
0,30	—	—	42	48	52	56	62	68	75	—
0,40	—	—	—	40	45	48	53	59	64	69
0,60	—	—	—	—	37	39	44	48	52	56
0,80	—	—	—	—	—	—	38	42	46	54
1,00	—	—	—	—	—	—	—	—	—	42

Table 2. Correction factors

Table 3. Turns and feed with different diameter of drill and drilling carbon steel

Types of holes in the metal and methods of their drilling

Types of holes:

• deaf;
• cross-cutting;
• half (incomplete);
• deep;
• large diameter;
• for internal threads.

Threaded holes require the definition of diameters with tolerances set in GOST 16093-2004. For widespread hardware, the calculation is shown in Table 5.

Table 5. The ratio of metric and inch threads, as well as selection of the size of the hole for deploying

Metric carving				Inch thread				Pipe thread
Diameter of thread	Thread step, mm	Thread diameter		Diameter of thread	Thread step, mm	Thread diameter		Diameter of thread	Thread diameter
		min.	max.			min.	max.
M1.	0,25	0,75	0,8	3/16	1,058	3,6	3,7	1/8	8,8
M1,4	0,3	1,1	1,15	1/4	1,270	5,0	5,1	1/4	11,7
M1,7	0,35	1,3	1,4	5/16	1,411	6,4	6,5	3/8	15,2
M2.	0,4	1,5	1,6	3/8	1,588	7,7	7,9	1/2	18,6
M2.6	0,4	2,1	2,2	7/16	1,814	9,1	9,25	3/4	24,3
M3.	0,5	2,4	2,5	1/2	2,117	10,25	10,5	1	30,5
M3.5	0,6	2,8	2,9	9/16	2,117	11,75	12,0	—	—
M4.	0,7	3,2	3,4	5/8	2,309	13,25	13,5	11/4	39,2
M5.	0,8	4,1	4,2	3/4	2,540	16,25	16,5	13/8	41,6
M6	1,0	4,8	5,0	7/8	2,822	19,00	19,25	11/2	45,1
M8.	1,25	6,5	6,7	1	3,175	21,75	22,0	—	—
M10.	1,5	8,2	8,4	11/8	3,629	24,5	24,75	—	—
M12.	1,75	9,9	10,0	11/4	3,629	27,5	27,75	—	—
M14	2,0	11,5	11,75	13/8	4,233	30,5	30,5	—	—
M16	2,0	13,5	13,75	—	—	—	—	—	—
M18	2,5	15,0	15,25	11/2	4,333	33,0	33,5	—	—
M20	2,5	17,0	17,25	15/8	6,080	35,0	35,5	—	—
M22	2,6	19,0	19,25	13/4	5,080	33,5	39,0	—	—
M24.	3,0	20,5	20,75	17/8	5,644	41,0	41,5	—	—

Through holes

Through holes permeate the workpiece completely, forming a passage in it. The peculiarity of the process is to protect the surface of the workbench or countertops from the release of the drill beyond the workpiece, which can damage both the drill itself, as well as supply the billet "Busken" - GARTA. To avoid this, the following ways are used:

• use workbench with hole;
• put under the part for a piece of wood or "sandwich" - wood + metal + tree;
• put under the part metal bar with a hole for the free passage of the drill;
• reduce the feed rate at the last stage.

The last method is required when driving holes "at the place" so as not to damage closely located surfaces or parts.

The holes in the thin metal metal are cut with perovy rods, because the spiral drill hurts the edge of the workpiece.

Deaf hole

Such holes are performed on a certain depth and do not permeate the workpiece through. You can measure the depth in two ways:

• limiting the length of the drill in the sleeve focus;
• limiting the length of the drill with a cartridge with adjustable focus;
• using a ruler fixed on the machine;
• combination of methods.

Some machines are equipped with an automatic feed system to a predetermined depth, after which the mechanism stops. In the process of drilling, you may need to stop working several times to remove the chips.

Holes of complex shape

Holes located on the edge of the workpiece (half) can be performed by connecting the edges and pressing two blanks or blanks and gasket and driving a complete hole. The gasket must be made of the same material as the workpiece being processed, otherwise the drill will "leave" in the direction of the smallest resistance.

The through hole in the corner (profile metal) is performed by fixing the workpiece in the vice and using a wooden gasket.

It is more difficult to perform the drilling of a cylindrical billet by tangent. The process is divided into two operations: preparation perpendicular opening of the site (milling, zenkovka) and the actual drilling. The drill of the holes in the surfaces located at an angle are also starting from the preparation of the site, after which the wooden gasket is inserted between the planes, forming a triangle, and drilled the hole through the angle.

Hollow parts are drilled by filling out the cavity of the tube from the wood.

Holes with ledges are obtained using two techniques:

1. Crew. The hole is drilled over the entire depth of the smallest diameter drill, after which it is drilled to a predetermined depth. The advantage of the method is a well-centered hole.
2. Reduce diameter. The hole of the maximum diameter is drilled on the predetermined depth, then the roller change with a sequential decrease in diameter and the recess of the hole. In this case, the method is easier to control the depth of each stage.

1. Development of the hole. 2. Reducing diameter

Large diameter holes, ring drill

Obtaining a large diameter holes in massive blanks, a thickness of up to 5-6 mm, the case is time consuming and cost. Relatively small diameters - up to 30 mm (a maximum of 40 mm) can be obtained using cones, and better step-conical swells. For larger diameter holes (up to 100 mm), hollow bimetallic crowns or crowns with carbide teeth with a centering drill will be needed. And the masters traditionally in this case recommended Bosch, especially on a solid metal, for example, steel.

Such an annular drilling is less energy-proof, but may be more costly financially. In addition to the roller, the power of a drill and the ability to work at the lowest revs. Moreover, the thickness of the metal, the stronger the hole in the machine will want, and with a large number of holes in a sheet with a thickness of more than 12 mm, it is better to immediately look for such an opportunity.

In a thin-plate billet, a large diameter hole is obtained using narrow-grained crowns or cutter, fixed on the "Bulgarian", but the edges in the latter case leave the best.

Deep holes, coolant

Sometimes it is required to perform a deep hole. In theory, it is a hole, the length of which is five times more diameter. In practice, deeply called drilling, requiring forced periodic removal of chips and the use of coolant (lubricating and cooling fluids).

In the coolant drilling is needed primarily to reduce the temperature of the drill and billets, which are heated by friction. Therefore, when obtaining holes in copper, which has a high thermal conductivity and itself is capable of removing heat, coolant can not be applied. Cast iron (except high-strength) is concerned relatively easily and without lubrication.

Industrial oils, synthetic emulsions, emulsols and some hydrocarbons are used in production. In domestic workshops you can use:

• technical Vaseline, castor oil - for soft steels;
• economic soap - for aluminum alloys of type D16T;
• kerosene mixture with castor oil - for duralumin;
• soap water - for aluminum;
• skipidar, diluted with alcohol - for silumin.

Universal cooled liquid can be prepared independently. To do this, it is necessary to dissolve 200 g of soap in a bucket of water, add 5 spoons of machine oil, can be used, and boil the solution until a soapy homogeneous emulsion is obtained. Some wizards to reduce friction use pork fat.

Processed material	Lubricating and coolant
Steel:
carbonistic	Emulsion. Heated oil
structural	Cereal oil with kerosene
instrumental	Mixed oils
alloyed	Mixed oils
Cast iron puffy	3-5% emulsion
Cast iron cast	Without cooling. 3-5% emulsion. Kerosene
Bronze	Without cooling. Mixed oils
Zinc	Emulsion
Brass	Without cooling. 3-5% emulsion
Copper	Emulsion. Mixed oils
Nickel	Emulsion
Aluminum and its alloys	Without cooling. Emulsion. Mixed oils. Kerosene
Stainless, heat-resistant alloys	A mixture of 50% of the drying oil, 30% kerosene, 20% oleic acid (or 80% sulfofresol and 20% oleic acid)
Fiber, viniplast, plexiglass and so on	3-5% emulsion
Textolit, Getinaks	Grinding with compressed air

Deep holes can be performed with solid and annular drilling, and in the latter case, the central rod formed by the rotation of the crown is not entirely, and with parts, weakening it with additional holes of the small diameter.

The solid drilling is performed in a well-fixed billet with a spiral drill, in the channels of which is supplied. Periodically, without stopping the rotation of the drill, it is necessary to extract it and purify the cavity from the chips. The work with a spiral drill is performed in stages: first they take a short and screw the hole, which then bueys the corresponding size drill. With a significant depth of the opening, it is desirable to use guide conductor sleeves.

With regular deletion of deep holes, you can recommend the purchase of a special machine with automatic coolant feed to the drill and accurate centers.

Drilling on markup, template and conductor

You can drill holes by setting up or without it - using a template or conductor.

Marking is performed by kerner. The hammer impact is planned for the tile of drill. Feltaster, too, you can mark the place, but the hole must also be so that the tip does not move from the intended point. The work is performed in two stages: pre-drilling, control of the opening, final drilling. If the drill "left" from the planned center, a narrow chisel is made of notches (grooves), sending the edge to a specified place.

To determine the center of the cylindrical billet, use a square piece of fusions bent under 90 ° so that the height of one shoulder is approximately one radius. Applying a corner from different sides of the workpiece, swipe along the edge. As a result, you have an area around the center. You can find the center by theorem - the intersection of perpendicular from two chords.

The template is needed when performing a series of uniform parts with multiple holes. It is convenient to use it for a pack of thin-leaf blanks, connected clamps. So at the same time, you can get a few drilled blanks. Instead of a template, sometimes the drawing or scheme is used, for example, in the manufacture of parts for radio equipment.

The conductor uses when the accuracy of the detention of distances between the holes and the strict perpendicularity of the channel is very important. When drilling deep holes or when working with thin-walled tubes, in addition to the conductor, guides can be used, locking the position of the drill relative to the metal surface.

When working with power tools, it is important to remember the safety of a person and premature the premature wear of the instrument and a possible marriage. In this regard, we collected some useful tips:

1. Before work, you need to check the attachments of all items.
2. Clothing when working on a machine or with an electric drill should not be with elements capable of entering rotating parts. Eyes from chips protect the glasses.
3. The drill when approaching the metal surface should be rotated, otherwise it quickly fills.
4. It is necessary to remove the drill from the hole without turning off the drill, if possible, reducing turnover.
5. If the drill does not deepen into the metal, it means that its hardness is lower than that of the workpiece. Increased hardness in steel can be revealed by spending on a sample with a file - the absence of traces indicates increased hardness. In this case, the drill must be chosen from solid alloy with additives and work on low revs with a small feed.
6. If the small diameter drill is poorly fixed in the cartridge, wrap on its shank several turns of brass wire, increasing the diameter to capture.
7. If the surface of the workpiece is polished, wear the felt washer on the drill to be guaranteed not to apply scratches even when contact with the drill patron. When fixing billets from polished or chrome steel, use gaskets from fabric or skin.
8. In the manufacture of deep holes, a rectangular piece of foam plastic, planted on the drill, can serve as a meter and simultaneously, rotating, blow up a small chips.

In such a simple way, it is possible not only a round hole in the calene steel, but also a hole of any other shape in no extra effort. The chemical way will help you and facilitate the task. The method does not require expensive chemical reagents, all ingredients can be found in any farm.

Need

I propose an easy way to spend holes in high-speed steel. To work will be required:

• any product from high-speed steel;
• marker;
• nail polish;
• liquid removal fluid (can be replaced with White spirit or acetone. I chose fluid only because of a pleasant smell, and this is the same acetone);
• wool;
• empty plastic container (bottle);
• salt;
• homemade device from the charger and two nails.

We make a hole in metal without drill

We apply on cotton liquid to remove varnish and degrease the surface of our workpiece.

We put the varnish on the desired area. Luck must be applied with a thick layer on both sides. Not forgetting thoroughly to miss ends. We leave the workpiece for 10-15 minutes to lacquer dry.

On the dried surface with a marker on both sides of the workpiece, I mark the place under the hole. Place I choose arbitrarily, now you need to show how this way you can make a hole. For example, it is required to put an ordinary factory rivet. The hole diameter should be slightly smaller than the rivet size.

Then remove the lacquer inside the loop contour. Do it on both sides.

In the container, pour water and add 3 tablespoons of salt. The height of the water in the tank should be 10 mm less than the height of the billet of the covered with varnish.

I take a fixture made from a charger machine for hair cutting and two nails. Nails will perform the function of the electrodes - I connected them to one contact. Another contact is simply a bare stripped wire. I use the 12 V charger, but a regular charger from a mobile phone can cope with such a task.

The stripped wire should be a plus, the electrodes are a minus. The positive wire with the help of linen clothespins is secure to our billet. Then we lower the nails into the water.

You can make slots in the container to fix the position of nails. Including the charger in the outlet. After turning on, the water around the nails-electrodes begins to bubble, and the purified label under the hole becomes black.

Note: To check the polarity of the wires, you need to connect the charger. If the water begins to bubble around nails, then it is minus and you connected correctly. The appearance of bubbles in water around the workpiece says that minus is connected to it and you need to cross the wires. The minus should always be connected to the electrodes, plus - to the workpiece processed by etching!
We leave the container for one hour, 30 minutes after the start of the process, it is necessary to change water. I turn off the charger and pull out the workpiece.

In the intended place, a through hole was formed. In order to make the hole diameter larger, the process can be continued. Or to write uneven edges with a supfyl.
This is how high-speed steel etching with the most ordinary items can be made in the workpiece to make the desired hole.

Metal processing is produced not only in industrial conditions. When performing repair work on the car, the manufacture of structures on the nursery or carrying out the repair of the home, the drilling of holes in the metal is necessary. At home, a manual drill is most often applied.

This universal tool requires certain skills to work with solid products. You can purchase, or make an independent machine for drilling holes in the metal, but it is not cheap pleasure.

The technologies of drilling holes in the metal is to remove the thin layer of material due to the simultaneous translational and rotational motion.

The main condition for high-quality and safe (for tool) processing is the hold of the axis of the cartridge in a fixed position. With the help of the machine, it is easy to maintain straightness, which you can not say when working with a hand tool.

If you are not sure of the hardness of the hands (this is a normal situation for an ordinary person), mechanical assistants are required for drilling at a right angle.

Immediately disclaim that additional conductors are required only in the case when the metal thickness exceeds the diameter of the drill.

If you make a hole in a thin steel plate, straightness does not matter.

There are several varieties of guides for manual electric drills. Mechanical drive tools are poorly suitable for work with metal, especially if it comes to accuracy.

1. Conductor for drilling. It is made in the form of a housing, convenient for retaining, inside which are placed sleeve-guides for drills of different diameters.


The material of the bushings is harder tool, so the holes are not wearing. By installing the conductor exactly above the center of the alleged hole, you can not worry about what the drill will "lead" from the specified direction.

This device is particularly useful when drilling perpendicular holes in small diameter pipes, when the tip strives to slip from the cylindrical surface.



2. Drill guide (manual). The reference device in which the tool is fixed for the neck


The sole is placed on the workpiece while holding the second hand for the handle. The drill moves strictly vertically, preventing breakdown and drill diluted.

The design may have an angular holder for pipes of a small diameter, which makes the device more versatile.

If there is a rotary mechanism, you also get a device for drilling holes at an angle.


True, the metal will not be drilled in this way, the side loads will quickly break the drill.

3. Rack for a drill (stationary floor). In fact, is an inexpensive alternative to the drilling machine.

To improve the main characteristics of the metal, it is often necessary for its hardening. Such technology provides for improving the hardness of the product due to strong heating of the metal and its rapid cooling. In some cases, after thermal processing, it is necessary to perform drilling. Due to the increase in such a characteristic, the drilling of Kalenny metal becomes more difficult. Consider all the features of drilling kalena steel more.

Drill hole in kalena steel

Distribution of the question, how to drill Kalenny Steel can be associated with the fact that when using ordinary technology, the tool is quickly blinking and comes to unsuitability. That is why it is necessary to pay attention to the specifics of the drilling of the Kalenny alloy. Among the features of the technology, we note the following points:

1. It is necessary to properly prepare a crawling workpiece.
2. In some cases, a special tool is required.
3. The coolant is used.

If necessary, you can make a drill for hardened steel with your own hands, for which certain equipment and skills are required. However, in most cases, the purchase options apply to the purchase options, as it can be better cope with the task when cutting Calen Steel.

Nuances when drilling

The technology under consideration has a fairly large number of features that need to be taken into account. Kalented metal drilling is carried out according to the following points:

1. Before working, the attention of the surface hardness should be paid. This parameter selects the most suitable drill. It is possible to determine the hardness when applying a wide variety of technologies.
2. During drilling there is a large amount of heat. That is why there is a rapid wear of the cutting edge. In this regard, in many cases, the cutting liquid is supplied to the cutting zone.
3. When cutting a hardware material, it has to sharpen the cutting edge from time to time. To do this, an ordinary sharpening machine or a special tool is applied. As an abrasive, an exclusively circle with a diamond spraying is suitable.

There are various methods for cutting kanenic steel. Some of them significantly simplify the processing. Only when taking into account all the nuances can be improved the quality of the obtained hole.

Useful techniques when drilling

A variety of technologies can be applied to working with Kalena Steel. The most common technologies are characterized by the following features:

1. Surface treatment with acid. This technology is characterized by long-term use, as it takes a fairly large amount of time to reduce surface hardness. Sulfur, chlorine or other acid can be used to etch. The procedure provides for the creation of a side, which will restrain the applied substance in the cutting zone. After a long exposure, the metal becomes softer, it will be possible to carry out drilling when using the usual version of the execution.
2. You can use a welding machine to achieve the goal. When exposed to high temperatures, the metal becomes softer, which greatly simplifies the procedures.
3. Most often a special drill is applied. The versions are found on sale, which can be used to treat Kalena steel. With their manufacture, the metal is used with increased wear resistance and high temperature exposure. However, the complexity of manufacture and some other moments determine that the cost of a special tool is quite high.

In addition, a missile is often purchased to achieve his goal. With it, you can make a small hole, which will simplify further drilling.

Use of lubricants

When drilling kaleno, serious friction occurs. That is why it is recommended to acquire and use various lubricants. Among the features of such a method of processing, we note the following points:

1. For starters, the drilling zone is processed. On the surface where the hole will be, a small amount of lubricant is applied.
2. Oil is added to the cutting edge. For colena processing, a small amount of substance is required, but it is necessary to add it from time to time, since when the tool is rotated it is split.
3. During work it is recommended to take breaks for cooling the cutting surface and the surface being treated.

Special oil allows not only to simplify drilling, but also to increase the service life of the applied tool.

This is due to the fact that the oil can reduce the temperature of the cutting edge.

Choosing a drill

Spiral drills, which are represented by a vertical rod with two grooves, were quite large. Due to a certain location of the grooves, the cutting edge is formed. Among the characteristics of the choice, we note the following points:

1. Pretty much spread received a winning drill. It can be used to work with various kalen alloys. However, the surface with too high hardness does not process like a tool.
2. The choice is carried out in the diameter indicator. It should be borne in mind that getting the hole of the large diameter is quite difficult. The version of the larger diameter is much more expensive due to the use of a large amount of material in its manufacture.
3. Attention is paid to the angle of sharpening, the purpose of the product and the type of material used in the manufacture. For example, cobalt versions are characterized by higher resistant to the effects of high temperature.
4. It is recommended to pay attention to the products of exclusively well-known manufacturers. This is due to the fact that Chinese version embodiments are manufactured using low-quality materials. However, such a proposal costs much cheaper and can be used for non-plum or disposable work.
5. When you select the drill, you can navigate the applied marking. It can determine which materials used in the manufacture of. Also indicates the diameter of the opening that can be obtained when using the tool.

In a specialized store you can find almost everything you need for work. However, a fairly high cost of the product and some other moments determine what some decide to produce drill on their own from the primary materials. Such work can be carried out in the presence of requiring tools.

Manufacture of self-made drill

If necessary, you can make the manufacture of drill from kalena steel. Among the basic recommendations for this work, we note:

1. Rods are selected, which are made of tungsten and cobalt alloys. In the people, such metal is called winning. In comparison with the usual drill, such an embodiment is characterized by increased resistance to wear.
2. For processing the workpiece you need to fix it in small visits. Otherwise, to carry out work will be quite complex.
3. To drain such a surface requires a diamond stone. The usual will not stand long work.
4. The end surface is sharpened so that the surface resembling a flat screwdriver is obtained. After that, the cutting edges are sharpened to obtain an acute tip.

In order to reduce the degree of surface time consumption, an oil is added. Due to this, long-term processing is provided due to reducing the friction force and temperature reduction.

In conclusion, we note that the treatment of kalena steel should be carried out exclusively when applying special tools. A drilling device is required for work, since manual will not allow the desired hole.

Today, each domestic master has a necessary tool for cutting metal, drilling, stripping. But what if you need to drill a hole of a large diameter? After all, the maximum cross section of the usual drill for manual electric drill is only 20 mm.

Fixtures for drilling big holes

There are several ways to drill a hole with a diameter of more than 20 mm. For this, special devices are applied:

• Cone drill. A large number of openings will fail to drill the same size. But for home use is quite acceptable. Maximum section - up to 40 mm. The thickness of the processed metal is 5-6 mm.
• Cone stepped drill. More convenient to use, since each step is formed by a smooth spiral transition. When drilling, this makes it easy to track the actual diameter of the opening. With it, you can drill a circle to 40 mm in diameter on metal with a thickness of up to 6 mm.
• Bimetallic crowns are suitable for the preparation of holes up to 109 mm in steel products with a thickness of up to 5 mm. When working, it is strongly recommended to use specialized lubricating and cooling formulations, which will ensure the maximum operational resource of the cutting tool. Also, adapter is needed to install the device to the electric drill. On average, with the help of a bimetallic crown, 5-20 openings can be drilled - depending on its quality, which, accordingly, is reflected in the cost.

How can you drill a large hole without excess costs?

For this method, it will take a small cross section (5-6 mm sufficient) drill, as well as the cutter or the spent circle (corresponding or slightly less than the hole diameter) for the grinder. An option is more time-consuming, so much more time is required.

On the metal harvesting pencil is scheduled for 2 circumference:

• 1 - for the future hole.
• 2 - depends on the cross section of the drill, that is, when using a 6 mm tool, the diameter of the outlined circle will be 6 mm less than the previous one.

On the 2nd circle, it is necessary to put 2 places in opposite places and drill holes with a drill of 6 mm. From the obtained openings on the planned line, it is necessary to retreat approximately 3 mm and put places for the drilling. The holes are drilled along the contour of the entire circumference. If necessary, the remaining areas can be filled with chisel.

The hole will be with jar, so it needs to be crowned. This can be performed by a mill with a cutter, but it is much more convenient - the grinder using the enraged abrasive circles of a suitable diameter. The grinder can be quickly and smoothly crowded the hole to the required diameter.

Therefore, it is not necessary to throw away the spent abrasive circles for the grinder with a diameter of even less than 45 mm - they can always come in handy in the farm.