What and how to drill deep and large holes in metal parts. Drilling precise holes with a drill. Secrets of craftsmanship Method of drilling large holes in 5mm metal

Drilling metal with a drill is somewhat more difficult than wood, brick or concrete. There are also some peculiarities.

For convenience, we have combined practical advice on this type of work into step-by-step instructions.

1. You will need the following tools: drill, drill, coolant (preferably machine oil, but water can also be used), punch, hammer, safety glasses.
2. When drilling metal on a horizontal surface, place it under the product wooden block and fix it as best as possible. When working in a vertical position, rigid fixation is extremely important, since drilling must be strictly perpendicular.
3. We make markings, then use a center punch and a hammer to mark the center of the future hole.
4. Pour coolant into a small container.
5. We put on safety glasses.
6. Let's start drilling. Do not put strong pressure on the drill, because it works better at low speeds. If the drill is powerful, then the method of short-term activation is suitable until the tool has time to reach maximum speed.
7. Don't forget to cool the drill as often as possible .
8. When drilling occurs not strictly perpendicularly, but at an angle, there is a high probability that the drill will jam. If this happens, put the switch in the reverse position. This way you will avoid injury and will not break the drill.
9. If you did everything correctly, then even at home, using a low-power drill, you can drill a hole in metal up to 5 mm thick inclusive and with a diameter of up to 10-12 mm. Oh more complex tasks we'll tell you below.

Metal drilling work

It is possible, but this is in case of extreme necessity for shallow holes with a small diameter. Unprofitable.

It is better to use either standard metal drills with steel grade R6M5 or improved ones - R6M5K5.

The letter K in the marking indicates that this is an alloy with the addition of cobalt. On the market you can find a drill called “Cobalt”. We will not vouch for all manufacturers, we will only note that reviews on practical application in the overwhelming majority of cases - positive.

How to drill with a step drill in metal?

Step drills are universal - just one can make holes of different diameters (from 2 to 40 mm). They are most effective when working with thin metal, when you need to get a neat edge. They are better fixed in the cartridge, they are easier to sharpen, and therefore, with proper use, they last longer, but they also cost more than usual. The principles of working with them are the same, but it is easier to drill holes large diameter than conventional twist drills.

Is it possible to drill metal with a Pobedit drill?

The principle of operation of drills for metal is to cut, and with pobedite soldering, crush materials. Brick, concrete, and stone are better suited for this. Therefore, as mentioned above, you can, of course, drill metal with a concrete drill, but it will quickly become unusable and pobedit soldering will collapse.

Revolutions

What is the larger hole diameter? the lower the speed should be. The greater the depth? Therefore, you gradually need to reduce the pressure on the drill. With a drill diameter of up to 5 mm, the torque should not be higher than 1200-1500 rpm. Accordingly, 10 mm in diameter - no more than 700 rpm, 15 mm - 400 rpm.

How to drill holes in large diameter metal?

As a rule, most drills for household use have a power from 500 to 800 W, which allows you to drill holes with a diameter of up to 10-12 mm.

How to properly drill metal thicker than 10 mm with an electric drill?

In metal up to 2 mm thick, using step drills you can make holes up to 40 mm. With a thickness of 3 mm, bimetallic crowns are better suited.

Bimetallic crown

When drilling deep holes with any tool, you may sometimes need a magnet to remove the chips.

Metal drilling process

Particular attention should be paid to safety precautions, be sure to protect your eyes from chips, and if there is distortion and jamming, immediately turn off the drill and change the torque to reverse movement.

In situations where there is no power or where the noise of the tool operating may disturb others ( read: when can you make repairs so as not to quarrel with your neighbors?) – the ideal solution when drilling metal would be a hand-held mechanical drill, the so-called rotator. Low speed and pressure, no overheating, just what you need. Of course, there are also disadvantages - time-consuming and easy fatigue. In this simple “old-fashioned” way, you can drill holes with a diameter of up to 10 mm.

We hope our tips will be useful to you.

More information in this video.

Coolant for metal cutting

Drilling of rolled metal: types and technology

The drilling procedure can easily be called one of the most important metal processing technologies.

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The main purpose of drilling is to produce mounting and technical holes of various diameters, depths and shapes, thread cutting, counterbore and countersinking. This procedure is carried out on drilling machines of various sizes and configurations. The MTS Center company also produces stuffed oil seals.

Using the drilling method, carried out on modern equipment, and the use of special tools, various operations are performed, among which the following can be distinguished:

· Drilling cylindrical holes;

·​ Drilling holes with an oval or multifaceted configuration;

·​ Drilling, countersinking and even grinding existing holes.

Drilling technology involves the possibility of producing both blind and through holes in metal structures of various sizes and shapes. At the same time, using special equipment equipped with CNC, it is possible to ensure high accuracy of holes and prepare a product, for example a sliding support, for subsequent assembly or further operations prescribed in the technological process.

This method is used for processing products or workpieces made from various types steels and cast iron. Naturally, for each material, a cutting tool (drill, countersink, reamer), as well as processing modes, lubrication and other parameters are individually selected.

This type of metalworking such as drilling is indispensable in various fields of industry, ranging from small businesses, engaged in small-scale production of components for equipment, and at large factories that have a full production cycle of a certain range of products. The processing accuracy, as well as the characteristics of the holes produced by drilling, directly depend on the machines, tools and technologies used.

Metal drills are selected based on the diameters of the holes and the properties of the material being processed. As a rule, they are made from high-speed steels, such as R6M5K5, R6M5, R4M2. Carbide drills are used to work with cast iron, carbon and alloy hardened steels, stainless steel, and other difficult-to-cut materials.

The power of the electric drill must be designed to drill a hole of the required diameter. Manufacturers of power tools indicate the corresponding specifications on the product. For example, for drills with a power of 500...700 W, the maximum drilling diameter for metal is 10...13 mm.

There are blind, incomplete, and through holes. They can be used to connect parts together using bolts, studs, pins and rivets. If a hole is drilled for threading, you should pay special attention to the choice of drill diameter. Due to its beating, a hole in the chuck occurs, which must be taken into account. Approximate data are presented in the table.

To reduce the breakdown, drilling is performed in two stages: first with a smaller diameter drill, and then with the main one. The same method of sequential drilling is used when it is necessary to make a hole of large diameter.

How to drill metal correctly with a drill

The peculiarity of drilling metal with a drill is that it is necessary to manually hold the tool, give it the correct position, and also ensure the required cutting speed.

After marking the workpiece, you should mark the center of the future hole. This will prevent the drill from moving away from the specified point. For ease of work, the workpiece should be clamped in a bench vice or placed on a stand so that it takes a stable position. The drill is installed strictly perpendicular to the surface to be drilled. This is important to avoid it breaking.

When drilling metal, you do not need to exert pressure on the drill. high pressure. On the contrary, it should decrease as you progress. This will prevent the drill from breaking and will also reduce the formation of burrs on the exit edge of the through hole. Care must be taken to remove chips. If the cutting tool is jammed, it is released by returning it to reverse rotation.

Selecting cutting mode

When using a high-speed steel tool, you can focus on the rotation speed according to the data in the table. When working with carbide drills permissible values ​​are 1.5...2 times higher.

Drilling of metal products must be carried out with cooling. If it is not used, there is a high probability that the tool will lose its cutting properties due to overheating. The cleanliness of the hole surface will be quite low. An emulsion is usually used as a coolant for hard steels. At home, machine oil is suitable. Cast iron and non-ferrous metals can be drilled without coolant.

Features of drilling deep holes

Holes are considered deep if their size is greater than five drill diameters. The peculiarity of the work here lies in the difficulties associated with cooling and chip removal. The length of the cutting part of the tool must be greater than the depth of the hole. Otherwise, the body of the part will block the screw grooves through which chips are removed and liquid for cooling and lubrication is supplied.

First, the hole is drilled with a rigid short drill to a shallow depth. This operation is necessary to set the direction and centering of the main tool. After this, a hole of the required length is made. As you progress, you need to remove metal shavings from time to time. For this purpose, use coolant, hooks, magnets, or turn the part over.

The work of drilling holes in metal, depending on the type of holes and the properties of the metal, can be performed different instruments and using various techniques.

We want to tell you about drilling methods, tools, as well as safety precautions when performing this work.

Drilling holes in metal may be necessary for repairs. engineering systems, household appliances, cars, creating structures from sheet and profile steel, designing crafts from aluminum and copper, in the manufacture of circuit boards for radio equipment and in many other cases. It is important to understand what tool is needed for each type of work so that the holes are of the required diameter and in the strictly intended location, and what safety measures will help avoid injuries.

Tools, fixtures, drills

The main tools for drilling are hand and electric drills, and, if possible, drilling machines. The working body of these mechanisms - the drill - can have different shapes.

Drills are distinguished:

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

Drill production various designs standardized by numerous GOSTs. Drills up to Ø 2 mm are not marked, up to Ø 3 mm - the section and steel grade are indicated on the shank; larger diameters may contain Additional information. To obtain a hole of a certain diameter, you need to take a drill a few tenths of a millimeter smaller. The better the drill is sharpened, the smaller the difference between these diameters.

Drills differ not only in diameter, but also in length - short, elongated and long are produced. The maximum hardness of the metal being processed is also important information. The drill shank can be cylindrical or conical, which should be kept in mind when selecting a drill chuck or adapter sleeve.

1. Drill with a cylindrical shank. 2. Drill with tapered shank. 3. Drill with a sword for carving. 4. Center drill. 5. Drill with two diameters. 6. Center drill. 7. Conical drill. 8. Conical multi-stage drill

Some jobs and materials require special sharpening. The harder the metal being processed, the sharper the edge should be sharpened. For thin sheet metal, a regular twist drill may not be suitable; you will need a tool with a special sharpening. Detailed recommendations for various types of drills and processed metals (thickness, hardness, type of hole) are quite extensive, and we will not consider them in this article.

Various types of drill sharpening. 1. For hard steel. 2. For stainless steel. 3. For copper and copper alloys. 4. For aluminum and aluminum alloys. 5. For cast iron. 6. Bakelite

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

To secure parts before drilling, vices, stops, jigs, angles, clamps with bolts and other devices are used. This is not only a safety requirement, it is actually more convenient, and the holes are of better quality.

To chamfer and process the surface of the channel, a cylindrical or conical countersink is used, and to mark the point for drilling and so that the drill does not “jump off”, a hammer and a center punch are used.

Advice! The best drills are still considered to be those produced in the USSR - they strictly follow GOST in terms of geometry and metal composition. German Ruko with titanium coating is also good, as well as drills from Bosch - proven quality. Good feedback about Haisser products - powerful, usually with a large diameter. The Zubr drills, especially the Cobalt series, performed well.

Drilling modes

It is very important to correctly secure and guide the drill, as well as select the cutting mode.

When making holes in metal by drilling, important factors are the number of revolutions of the drill and the feed force applied to the drill, directed along its axis, ensuring the depth of the drill with one revolution (mm/rev). When working with different metals and drills, different cutting modes are recommended, and the harder the metal being processed and the larger the diameter of the drill, the lower the recommended cutting speed. An indicator of the correct mode is beautiful, long chips.

Use the tables to choose the right mode and avoid dulling the drill prematurely.

Feed S 0 , mm/rev	Drill diameter 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. Revolutions and feed for different drill diameters and drilling carbon steel

Types of holes in metal and methods of drilling them

Types of holes:

• deaf;
• end-to-end;
• half (incomplete);
• deep;
• large diameter;
• for internal thread.

Threaded holes require diameters to be determined with the tolerances established in GOST 16093–2004. For common hardware, the calculation is given in Table 5.

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

Metric thread				Inch thread				Pipe thread
Thread diameter	Thread pitch, mm	Threaded hole diameter		Thread diameter	Thread pitch, mm	Threaded hole diameter		Thread diameter	Threaded hole 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 penetrate the workpiece completely, forming a passage through it. A feature of the process is to protect the surface of the workbench or tabletop from the drill going beyond the workpiece, which can damage the drill itself, as well as provide the workpiece with a “burr” - a burr. To avoid this, use the following methods:

• use a workbench with a hole;
• put a wooden gasket or a “sandwich” under the part - wood + metal + wood;
• place a metal block with a hole for free passage of the drill under the part;
• reduce the feed rate at the last stage.

The latter method is required when drilling holes “in situ” so as not to damage nearby surfaces or parts.

Holes in thin sheet metal are cut with feather drills, since a twist drill will damage the edges of the workpiece.

Blind holes

Such holes are made to a certain depth and do not penetrate through the workpiece. There are two ways to measure depth:

• limiting the length of the drill with a sleeve stop;
• limiting the length of the drill with a chuck with an adjustable stop;
• using a ruler attached to the machine;
• a combination of methods.

Some machines are equipped with an automatic feeding system to a given depth, after which the mechanism stops. During the drilling process, you may need to stop work several times to remove chips.

Holes of complex shape

Holes located on the edge of the workpiece (half holes) can be made by connecting the edges and clamping two workpieces or a workpiece and a spacer with a vice and drilling a full hole. The spacer must be made of the same material as the workpiece being processed, otherwise the drill will “go” in the direction of least resistance.

A through hole in a corner (profiled metal) is made by fixing the workpiece in a vice and using wooden spacer.

It is more difficult to drill a cylindrical workpiece tangentially. The process is divided into two operations: preparing a platform perpendicular to the hole (milling, countersinking) and the actual drilling. Drilling holes in surfaces located at an angle also begins with preparing the site, after which a wooden spacer is inserted between the planes, forming a triangle, and a hole is drilled through the corner.

Hollow parts are drilled, filling the cavity with wood plug.

Shouldered holes are produced using two techniques:

1. Reaming. The hole is drilled to the full depth with a drill of the smallest diameter, after which it is drilled to a given depth with drills of diameters from smaller to larger. The advantage of the method is a well-centered hole.
2. Reducing the diameter. A hole of maximum diameter is drilled to a given depth, then the drills are changed with a successive decrease in diameter and deepening of the hole. With this method it is easier to control the depth of each step.

1. Drilling a hole. 2. Diameter reduction

Large diameter holes, ring drilling

Producing large-diameter holes in massive workpieces up to 5–6 mm thick is labor-intensive and costly. Relatively small diameters - up to 30 mm (maximum 40 mm) can be obtained using conical, or better yet, stepped conical drills. For larger diameter holes (up to 100 mm), you will need hollow bimetallic bits or bits with carbide teeth with a center drill. Moreover, craftsmen traditionally recommend Bosch in this case, especially on hard metal, such as steel.

Such annular drilling is less energy-intensive, but can be more costly financially. In addition to drills, the power of the drill and the ability to work at the lowest speeds are important. Moreover, the thicker the metal, the more you will want to make a hole on the machine, and when large quantities holes in a sheet more than 12 mm thick, it is better to immediately look for such an opportunity.

In a thin-sheet workpiece, a large-diameter hole is obtained using narrow-toothed crowns or a milling cutter mounted on a grinder, but the edges in the latter case leave much to be desired.

Deep holes, coolant

Sometimes it is necessary to make a deep hole. In theory, this is a hole whose length is five times its diameter. In practice, deep drilling is called drilling that requires forced periodic removal of chips and the use of coolants (cutting fluids).

In drilling, coolant is needed primarily to reduce the temperature of the drill and workpiece, which heat up from friction. Therefore, when making holes in copper, which has high thermal conductivity and is itself capable of removing heat, coolant may not be used. Cast iron can be drilled relatively easily and without lubrication (except high-strength).

In production, industrial oils, synthetic emulsions, emulsols and some hydrocarbons are used as coolants. In home workshops you can use:

• technical petroleum jelly, castor oil - for soft steels;
• laundry soap - for aluminum alloys type D16T;
• a mixture of kerosene and castor oil - for duralumin;
• soapy water - for aluminum;
• turpentine diluted with alcohol - for silumin.

Universal refrigerated liquid can be prepared independently. To do this, you need to dissolve 200 g of soap in a bucket of water, add 5 tablespoons of machine oil, or used, and boil the solution until a homogeneous soap emulsion is obtained. Some craftsmen use lard to reduce friction.

Processed material	Cutting fluid
Steel:
carbon	Emulsion. Sulfurized oil
structural	Sulfurized oil with kerosene
instrumental	Mixed oils
alloyed	Mixed oils
Malleable cast iron	3-5% emulsion
Iron casting	No cooling. 3-5% emulsion. Kerosene
Bronze	No cooling. Mixed oils
Zinc	Emulsion
Brass	No cooling. 3-5% emulsion
Copper	Emulsion. Mixed oils
Nickel	Emulsion
Aluminum and its alloys	No cooling. Emulsion. Blended oils. Kerosene
Stainless, heat-resistant alloys	A mixture of 50% sulfur oil, 30% kerosene, 20% oleic acid (or 80% sulforesol and 20% oleic acid)
Fiberglass, vinyl plastic, plexiglass and so on	3-5% emulsion
Textolite, getinaks	Blowing with compressed air

Deep holes can be made by continuous or circular drilling, and in the latter case, the central rod formed by the rotation of the crown is broken out not entirely, but in parts, weakening it with additional holes of small diameter.

Solid drilling is performed in a well-fixed workpiece with a twist drill, into the channels of which coolant is supplied. Periodically, without stopping the rotation of the drill, you need to remove it and clear the cavity of chips. Working with a twist drill is carried out in stages: first, take a short hole and drill a hole, which is then deepened with a drill of the appropriate size. For significant hole depths, it is advisable to use guide bushings.

When regularly drilling deep holes, we can recommend purchasing a special machine with automatic coolant supply to the drill and precise alignment.

Drilling according to markings, templates and jigs

You can drill holes according to the markings made or without it - using a template or jig.

The marking is done with a center punch. With a hammer blow, a place is marked for the tip of the drill. You can also mark the place with a felt-tip pen, but the hole is also needed so that the point does not move from the intended point. The work is carried out in two stages: preliminary drilling, hole control, final drilling. If the drill has “moved away” from the intended center, notches (grooves) are made with a narrow chisel, directing the tip to the specified location.

To determine the center of a cylindrical workpiece, use a square piece of sheet metal, bent at 90° so that the height of one arm is approximately one radius. Applying a corner from different sides of the workpiece, draw a pencil along the edge. As a result, you have an area around the center. You can find the center using the theorem - the intersection of perpendiculars from two chords.

A template is needed when making a series of similar parts with several holes. It is convenient to use for a pack of thin-sheet workpieces connected with a clamp. This way you can get several drilled workpieces at the same time. Instead of a template, a drawing or diagram is sometimes used, for example, in the manufacture of parts for radio equipment.

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

When working with power tools, it is important to remember human safety and prevent premature wear of the tool and possible defects. In this regard, we have collected some useful tips:

1. Before work, you need to check the fastenings of all elements.
2. When working on a machine or with an electric drill, clothing should not contain elements that could be affected by rotating parts. Protect your eyes from chips with glasses.
3. When approaching the metal surface, the drill must already be rotating, otherwise it will quickly become dull.
4. You need to remove the drill from the hole without turning off the drill, reducing the speed if possible.
5. If the drill does not penetrate deep into the metal, it means that its hardness is lower than that of the workpiece. Increased hardness of steel can be detected by running a file over the sample - the absence of traces indicates increased hardness. In this case, the drill must be selected from carbide with additives and operated at low speeds with low feed.
6. If a small-diameter drill does not fit well in the chuck, wrap a few turns of brass wire around its shank, increasing the grip diameter.
7. If the surface of the workpiece is polished, put a felt washer on the drill to ensure that it does not cause scratches even when it comes into contact with the drill chuck. When fastening workpieces made of polished or chrome-plated steel, use fabric or leather spacers.
8. When making deep holes, a rectangular piece of foam placed on a drill can serve as a meter and at the same time, while rotating, blow away small chips.

Good mood to everyone! Today we’ll look at the issue of drilling precise holes in solid metal with a drill. The topic may seem quite simple, but still, there are certain secrets of skill, having mastered which you will drill holes with particular ease.

Drilling holes in metal using a drill and special tools.

At home, it is often necessary to drill holes in metal to install fasteners and other mechanical parts. Although in some cases it is possible to drill holes quite accurately using a conventional hand-held electric drill, to obtain high-quality work, you should use a vertical drilling machine. To change the rotation speed of the machine, you need to move the drive belt from one pulley to another.

Drill selection.

Regardless of the drilling device used, the size and shape drilled hole determined by the drill used. A cylindrical hole (sometimes not entirely correct geometrically) is usually drilled with a twist drill. This drill is a pointed metal cylinder with a spiral channel running along the axis of the drill. In soft metals such as aluminum and copper, these drills often produce holes with jagged edges. To drill such metals, you can use a drill for sheet material, which is made in the form of a cone and has one cutting edge on the side.

Holes in metal should always be drilled using high-speed drills. Made from the hardest steels, these drill bits range in diameter from 0.5mm to 25mm or more.

Marking of drills and design features.

One of the options for marking drills (according to sizes) is to indicate their diameter in millimeters. To drill large recesses, you can install a hole saw instead of a drill - a cylinder with teeth that can cut holes up to 150 mm in size and a depth of up to two-thirds of the height of the saw itself. You can also use a special drill, which differs from the usual one by the presence of an elongated L-shaped cutting edge. Special drills are available for drilling conical or cylindrical recesses for the heads of fasteners, such as bolts, rivets or screws.

To give the drilled hole precise geometric dimensions, provided that the diameter of this hole does not exceed 35 mm, it is necessary to process it with a reamer. This processing is done manually or on a machine. Hand reamers are straight drills with four or more cutting edges that gradually machine the inside of the hole as they rotate. Machine reamers are installed in vertical drilling machines.

Precise drilling of metal on a machine.

When drilling precise holes, you should always use a special cutting fluid that reduces friction and cools the drill during operation. In addition, it is necessary to use clamps and a vice for precise, stationary installation of the workpiece. When marking the drilling site, you should use a center punch, with which a small depression is made at the drilling site.

When drilling on a machine, to determine the position of the hole, you need to use a ruler to draw two short lines intersecting at right angles in the center of the hole. To prevent the drill from slipping, it is necessary to make a small depression in the found center using a center punch and a hammer.

Determination of tool rotation parameters.

Determine the required rotation speed and set the machine to rotate at this speed. To set the rotation speed, you need to open the casing cover and loosen the belt tension by unscrewing the handle that secures the motor in the casing. To change the speed, the engine moves forward and the belt is moved from one level of pulleys to another in accordance with the necessary change in speeds, which are determined from the nameplate or operating instructions. The lowest speed is achieved when the belt is placed in its lowest position - between the smallest motor pulley and the largest spindle pulley. On the contrary, the highest speed is achieved when the belt is installed in the uppermost pulleys. Next, you need to make sure that the belt is tensioned horizontally between the pulleys, move the engine to its original position and tighten the knob securing the engine to the casing.

Setting up tools and fixtures.

Before drilling begins, the drill is installed in the chuck and tightened. Don't forget to adjust the vertical movement of the spindle by lowering the drill along the workpiece and moving the stopper to the desired point on the graduated stopper movement scale. The spindle rises to a height sufficient to install the workpiece under the drill and is fixed in this position. The workpiece is moved so that the intended hole is exactly under the drill. The workpiece is clamped securely before drilling begins.

Subsequently, it is necessary to lower the spindle sleeve lock and turn on the drilling machine. Squeeze a drop of coolant and lubricant onto the recess, lower the drill with the lever and start drilling. Even pressure should be applied during operation. A brush is used to remove shavings and sawdust. The appearance of smoke from the drilled hole indicates the need to check the color of the metal shavings. They should be white or straw yellow. Blue color means overheating. In this case, you need to add cutting fluid or reduce the rotation speed. After finishing drilling, you must slowly release the feed handle and turn off the machine.

Drilling precise holes in metal with a hand drill.

If there is no need to maintain the accuracy that a vertical drilling machine provides, you can use a powerful hand-held electric drill. However, if this drill is not multi-speed, then when drilling holes in metal, it should be turned on for short periods of time by briefly pressing the switch in succession.

The key to success in most cases depends on how you hold the drill. Before drilling begins, the workpiece is clamped in a vice or pressed firmly to the table. Then, without turning on the drill, the end of the drill is installed on the point marked with the center punch. To increase the starting point, you can manually rotate the drill chuck several times while pressing down on the drill bit. After applying the cutting fluid, the voltage will turn on. The drill body is held motionless with the left hand, the tool itself is pressed with the right hand when the drill begins to increase speed. If possible, place a vertical square next to the drill to make it easier to install the drill in a vertical position. This will make it easier to drill precise holes.

If the drill cannot go deep into the surface of the metal workpiece, a second, larger depression is made using a center punch at the desired point.

Safety precautions when working with a hand drill.

When working with drills, one should not neglect the rules. To prevent the risk of accidents when drilling metal products, the following instructions must be strictly adhered to:

• It is prohibited to drill a product that is held only by hands;
• It is forbidden to work with dissolute long hair or wearing loose clothing that is not fastened, as well as wearing gloves, since there is a danger of the glove material being caught by the drill;
• Safety glasses should not be neglected;
• Before turning on the machine, make sure that the drill in the chuck is tightened tightly and the key is removed.

Perhaps we'll end here. Drilling precise holes in metal is useful not only at home but also when performing industrial tasks.

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Drilling through holes in metal workpieces is done with various tools using special techniques. Many specialists, when performing engineering work, have to drill holes in metal structures often. These objects have high elasticity, which forces the use of special cutting devices when drilling.

Types of drills and devices for drilling in metal

Necessary equipment for drilling metal products - electrical and hand drills, as well as drilling machines. The working part of such devices is a drill of different shapes:

• spiral;
• screw;
• crown-shaped;
• conical;
• flat;
• cannon;
• rifle;
• centering;
• stepped.

Each drill is individually marked, where the tip indicates the cross-sectional diameter and the type of alloy from which it is made. To drill a hole of the required diameter, you need a drill a few tenths of a millimeter narrower.

Drills are also classified by length:

• short;
• elongated;
• long.

Drilling in some materials may require a specially sharpened diamond-tipped drill bit. Twist drills may not be able to handle products made from thin sheet alloys. In some cases, to drill deep holes, the product must be fixed in a vice, stops, jigs, or corners with fasteners. This is done for safety reasons and to obtain high quality holes.

Modes for drilling holes in metal products

For drilling through holes in metal products Preliminary preparation for the process is extremely important. The drill must be correctly secured and guided in the tool. You need to adjust the rotation speed and other parameters. For products that are too strong, a low drill speed is recommended. An indicator of correct drilling should be uniform, long chips.

Types of holes and methods for drilling them

Some manufacturing jobs often require the following types of holes in metal workpieces:

1. Through. They completely pierce metal workpieces. It is important to protect the surface of the machine from accidental exit of the drill beyond the product to avoid damage to the drill and the occurrence of burrs on the blank. Workbenches with holes, where it is possible to place a wooden spacer under the workpiece, are ideal for such types of work. Holes in thin blanks are drilled with flat drills, because a twist drill can noticeably destroy the edges of the product.
2. Deaf. They are carried out to the required depth without penetrating the product right through. IN in this case An important point is measuring the depth, which can be conveniently done by limiting the length of the drill with the stop of the sleeve or the drill chuck with a locking stop. Professional machines are equipped automatic systems feed to the specified penetration size, which allows you to fix the depth of the drill.
3. Deep. This type of hole includes those drills whose length is five times the diameter. When drilling deep holes, it is necessary to periodically remove the resulting chips using additional lubricants. Often it is necessary to enforce measures to cool the drill and the workpiece itself, the temperature of which rapidly rises to too high levels as a result of friction. This applies to workpieces made of high-strength alloys. For deep holes, twist drills are used.
4. Wide diameter. Drilling large-diameter holes in products of large proportions is a very responsible and labor-intensive process. For such holes, conical, crown-shaped or stepped drills are used. Specialists carry out drilling at low tool speeds, trying to ensure the safety of the edges of the workpiece.
5. Complex shape. Sometimes it is necessary to drill through or blind holes in workpieces of different densities for internal threads. The technology has to be divided into two actions: preliminary preparation of the site and the drilling itself.
6. Half-hearted. Half blanks are drilled, filling the cavities with wood. Stepped holes can be obtained using one of two techniques: reaming (passing a drill of a smaller diameter to the entire depth of the workpiece, followed by drilling with drills of a larger diameter) and reducing the diameter (drilling a hole of a larger diameter to the required depth, followed by replacing a drill with a smaller diameter). As a result, the hole is clearly centered.

Safety when drilling holes in metal workpieces

When drilling holes in metal workpieces, you should be very careful to avoid rapid destruction of the drill. Following simple rules when drilling will ensure safety and guarantee a high-quality product upon completion of the work:

1. On the eve of drilling, you must carefully check the fixation of all fastening devices on the machine.
2. You can start work in special clothing to prevent any elements from getting under the moving parts of the machine. Eyes from getting hit metal shavings Protect with special glasses.
3. When the drill tip enters a metal workpiece, it should already be rotating at low speeds to avoid dulling.
4. The drill should be pulled out of the drilled hole gradually, reducing the speed, but not stopping completely.
5. When the drill tip does not penetrate into the workpiece, you will have to check the strength of the metal. When running a file over the surface, it is possible to determine the degree of strength. If there is no roughness left on the alloy, you need to choose a drill with a diamond tip or from a harder material, and drill at low speeds.
6. Drills of small diameter, which are difficult to fix in the chuck, are recommended to be wrapped with brass wire on the tail to increase the diameter of the girth.
7. If you are working with a polished workpiece, you can put a felt washer on the base of the drill to avoid damage when it comes into contact with the drill chuck.
8. To fix metal workpieces made of polished or chrome-plated steel, fabric or leather spacers are used.
9. When drilling deep holes, a small piece of compressed foam placed on the drill will ensure that small metal shavings are blown away. Also, foam plastic will make it possible to deepen the drill to the required level when producing blind holes.

Power electric drills must be taken into account when drilling holes in metal workpieces of varying hardness. Manufacturers of electric tools mark devices by indicating technical characteristics on their housing. For drills of different power, drills of the appropriate diameter are required.

You can entrust any tasks, including drilling, to the specialists of the Proflazermet company. We ourselves will determine the required hole diameter and select the appropriate tool, of which we have a large selection. As a result, you will get the perfect solution in a short time.