Often when working with wood and wood-based materials, it becomes necessary to drill an even round hole. You can use a jigsaw or a router, but such a tool is not always at hand or it is simply inconvenient to do the work with them. A woodworking ballerina can make the task easier.
What is a wood ballerina
Circular adjustable ballerina drill - a device that is designed for drilling round holes large diameter. The tool has simple design. It consists of a shank with a transverse rod on which movable carriages with cutters are attached. The rod has markings according to which you can set the required spread of the cutters relative to the center of the intended hole. A core drill is fixed in the middle of the shank. It serves as a centering element and support when drilling.
In addition to designs with two cutting elements located symmetrically, there are ballerinas with one cutter or even three. In the latter case, they are located on the base in the form of a disk with grooves.
Tool functionality
A high-quality ballerina is made of high-strength steel, which makes it possible to use the device in working with soft and hard wood.
This tool has an adjustable drilling diameter. This allows you to make holes of almost any diameter. The limitation of the drilling range depends on the size of the ballerina. Manufacturers produce devices with the following cutter spread limits:
- from 30 to 120 mm;
- from 40 to 200 mm;
- from 40 to 300 mm;
- from 40 to 400 mm.
The maximum drilling diameter is limited by the rod on which the cutters are mounted. The minimum is the thickness of the shank.
The ballerina drill can be used in any places where the use of a jigsaw or hand router will be inconvenient. For example, this could be assembled and installed furniture, in the parts of which you need to drill a neat hole, taking into account limited space. Another example is an uneven (curved or concave) surface. It’s unlikely that you’ll be able to do everything smoothly and neatly with a jigsaw or milling cutter. It will be difficult to control the inclination of the tool relative to the surface. A ballerina can easily cope with this task.
Features of working with the tool
The principle of working with a circular drill is simple. A hole is drilled using a centering drill, and then the cutters are put to work. They gradually make a narrow groove, gradually cutting through the material in a circle to the full depth.
The materials used in working with the ballerina are varied: wood, fiberboard, chipboard, MDF, plasterboard, plastic. One common point is that the thickness of the part should be no more than 15-20 millimeters. This parameter is limited by the length of the incisors. Usually the manufacturer indicates maximum depth drilling on the packaging. If you try to drill into thicker material, you may experience problems with ragged edges.
The use of a tool with one cutter is characterized by runout. This is caused by a lack of balancing relative to the longitudinal axis of the drill. The beating will be especially noticeable when cutting large diameter holes. Cut holes using a drill at low or medium speed. When working on a drilling machine, such problems do not arise.
Also, a laminated or veneered surface can cause inconvenience when working. After passing through the decorative layer, drilling proceeds without problems.
A feature of the circular drill can be considered the ability to adjust the diameter. The distance between the cutters can be set using a scale on a rod or more accurately using a caliper. This is convenient if you need to make a hole without gaps for a pipe or round part.
The spacing of the cutters relative to the center is adjusted individually. It is necessary to align the cutting parts as accurately as possible. This will get rid of extra effort during operation and will extend the life of the tool.
How to choose and what to pay attention to
Choosing a high-quality circular drill is quite easy. The main thing is to know the main points that you should pay attention to first, but also not to lose sight of the little things.
The design is a very important point: a wood ballerina comes with one chisel or two or more. For frequent use, it is better to purchase an option with two or three cutting elements. It is easier to work with such devices and the quality of the processing performed will be at an acceptable level.
It wouldn't hurt to replace it individual parts. Inexpensive circle drills can have a solid shank with a permanent center drill and rod.
Metal, its quality determines its strength and ability to withstand workloads. Quality tool made of high-strength steel or alloys. The shank and cutter holders are shaped using a machine tool. The rod is usually stamped and made of the same metal.
Cheap options often use soft metal or alloys, which can be brittle. Under load, parts may become deformed or break. Such a tool will not last long and it will also be difficult to achieve accuracy from it.
The quality of workmanship, the main feature is the absence of backlashes and distortions. All parts must fit together and be securely fastened with fixing screws.
The markings of a high-quality ballerina's barbell are stamped. Sometimes the divisions are highlighted with bright paint for better visibility.
Cutters and high-quality cutting elements are made from hardened tool steel. They are secured to the holders with rivets or soldering. Solid cutters with holders (made of the same metal) quickly become dull and are not durable.
Manufacturer, when choosing any tool and consumables, preference should be given to well-known and long-proven brands and brands. The most common are Topfix, Stayer, Irwin, Strum.
Purchasing an adjustable circular drill for use at home, or if you need to drill several holes, is completely worth it. This eliminates the need to purchase an expensive tool that may only be needed a few times.
Metal processing is carried out not only in industrial conditions. By doing repair work on a car, manufacturing structures for personal plot or carrying out home renovations, it is necessary to drill holes in the metal. At home, a hand drill is most often used.
This universal tool Requires certain skills in working with solid products. You can purchase or make your own machine for drilling holes in metal, but this is not a cheap pleasure.
The technology of drilling holes in metal involves removing a thin layer of material through simultaneous translational and rotational motion.
The main condition for high-quality and safe (for the tool) processing is keeping the chuck axis in a fixed position. Using the machine it is easy to maintain straightness, which cannot be said when working with hand tools.
If you are not confident in the steadiness of your hands (this is a normal situation for ordinary person), for drilling at right angles, mechanical assistants (conductors) are required.
Let us immediately make a reservation that additional conductors are required only in the case when the thickness of the metal exceeds the diameter of the drill.
If you are making a hole in a thin steel plate, straightness does not matter.
There are several types of guides for hand-held electric drills. Power-driven tools are not suitable for working with metal, especially if we're talking about about accuracy. 
- Drilling jig. It is made in the form of a housing that is easy to hold, inside which there are guide bushings for drills of various diameters.
- Guide for drill (manual). Supporting device in which the instrument is fixed by the neck
- Drill stand (semi-stationary). In fact, it is an inexpensive alternative to a drilling machine.
The material of the bushings is harder than the tool, so the holes do not wear out. By installing the jig exactly above the center of the intended hole, you don’t have to worry that the drill will “lead” away from the given direction.
This device is especially useful when drilling perpendicular holes in pipes of small diameter, when the tip tends to slip off cylindrical surface.
The sole is placed on the workpiece, held by the handle with the second hand. The drill moves strictly vertically, preventing distortions and drifts of the drill.
The design can have a corner holder for small-diameter pipes, which makes the device more versatile.
In the presence of rotary mechanism, you also get a device for drilling holes at an angle. 
True, it will not be possible to drill metal in this way; lateral loads will quickly break the drill.
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, car, 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 made required diameter and in a strictly designated place, and what safety measures will help avoid injury.
Tools, fixtures, drills
The main tools for drilling are hand and electric drills, and also, if possible, drilling machines. The working part of these mechanisms - the drill - can have different shapes.
Drills are distinguished:
- spiral (most common);
- screw;
- crowns;
- conical;
- feathers, etc.
The production of drills of various designs is 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 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 of 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 - exact adherence to GOST in geometry and metal composition. German Ruko with titanium coating are 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 various metals and drills, various 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 special 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:
- 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.
- 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 mild 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 solid and ring 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.
If you regularly drill deep holes, we can recommend purchasing a special machine with automatic feeding Coolant 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 with different sides blank, draw a pencil along the edge. As a result, you have an area around the center. You can find the center using the theorem - by 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 thin sheet blanks, connected by 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:
- Before work, you need to check the fastenings of all elements.
- 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.
- When approaching the metal surface, the drill must already be rotating, otherwise it will quickly become dull.
- You need to remove the drill from the hole without turning off the drill, reducing the speed if possible.
- 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 hard alloy with additives and operate at low speeds with low feed.
- 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.
- 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.
- 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.
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 the hole is drilled for the purpose of threading, it is worth turning Special attention to choose the 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 apply much pressure to the drill. 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 jamming occurs cutting tool, he is released by putting him in 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, the permissible values are 1.5...2 times higher.
Drilling metal products must be done 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. Suitable for home use machine oil. 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.
Metal processing is one of the rather complex operations. Drilling may be required when repairing premises or your own car, as well as manufacturing various designs on summer cottage. As with any other holes, we will need a hand drill, which can be supplemented with various additional devices. Although a drill is a very popular and in-demand tool, available in almost every home, it requires considerable experience in metal processing. In our article we will talk about metal drilling, drills and some of the features of this labor-intensive process.
Tools and drills - what we need for drilling
Drilling holes in metal is special technology, which consists in removing a certain layer of material due to the simultaneous rotational and translational movement of the drill. It is necessary to fix the drill in one position so that the drill does not move during operation. This is the main condition for the correct and safe performance of work. To ensure that the drill axis is in a fixed position, you can use one of the many devices, which will be discussed below.
We will need the following tools for working with metal:
- Hand or electric drill
- Twist drill
- Hammer
- Kerner
- Safety glasses and gloves
It will be impossible to achieve success in the planned event without the appropriate drill. The choice of this element is a very important point, because different drills are selected based on the properties of the metal, as well as the diameter of the future hole. Drills are usually made from high-speed steel. The most common are products made from steel grade R6M5. In some cases, cobalt additives are used to increase the durability and wear resistance of the drill. In this case, the letter K appears in the product labeling. For very hard metals, drills are used that are equipped with a small solder on the tip, which ensures the required level of drilling of the material.
You should know that not all drills are capable of making exactly the holes that you need. Thus, the manufacturer usually indicates the relevant information in the instruction manual. For example, drilling a large diameter hole with a drill whose power is 700 W will not work. After all, this equipment is designed to create a hole maximum size 13 mm in diameter.
Accessories for drills - how to make your life easier
Drilling into metal is difficult for many people, even experienced craftsmen. One reason is the physical complexity of the process itself. After all, it is necessary to hold a heavy drill at a right angle in a clearly fixed position for a long time. However, you can always use additional accessories designed to make the whole process easier.
IN construction stores You can purchase the following mechanisms for perpendicular drilling of holes in metal products:
- 1. Drilling jigs
- 2. Drill guides
- 3. Drill stands
Conductors are extremely popular; it is with their help that specialists make holes in products. The mechanism itself is a kind of box, convenient to hold, in which guide bushings are located. Suitable for working with drills of various diameters. The bushings are made of very hard types of metal, much harder than the drill itself. Therefore, there is no need to worry that they will be damaged when working with a drill.
You just need to place the jig over the location of the future hole, previously marked with a center punch, and then turn on the drill. The drill will be firmly fixed by the bushings, so it will not move away from the given direction. The jig is considered especially useful when drilling cylindrical, for example, pipes, since the drill tip constantly slips off round shape pipes.
You can also purchase guides for hand drill- This is a useful support mechanism where the drill is fixed by the neck to achieve immobility during operation. The sole, held by the free hand, is installed on the workpiece itself. In this state of affairs, the tool moves exclusively vertically, without the slightest deviation or distortion.
Today, universal designs are produced, equipped with a corner holder. Thanks to this, you can drill holes with a drill even at an angle. True, in the case of metal, drilling at an angle using guides is very difficult, since lateral overloads almost immediately break the drill. Therefore, you need to take care when purchasing a product made of solid metal.
Another device that simplifies the hole making process is called a stationary stand. At its core, this equipment is a somewhat simplified drilling machine, however, with less functionality, but also significantly lower cost. The drill moves along the rod using a lever. Clamps or a vice are used to secure the workpiece. In terms of drilling quality, this unit is an order of magnitude higher than its other competitors. However, its price is also higher compared to jigs or guides.
Deep holes - what makes them special
The process of drilling holes in metal products differs significantly depending on the thickness of the workpiece. Deep holes are much more difficult to make compared to regular ones. For such cases, specialists use lathes, and it is the workpiece that must rotate, and not the drill itself on the machine. An important point is the removal of waste and chips from the part, as well as cooling the drill.
Naturally, it is unlikely that you will be able to use a lathe at home. The only way out is to purchase drill guides, which were described above. Drill length is great importance, since the drill can only make holes two-thirds of its length. So you need to purchase long drill, but strong enough that it will not break under the influence of enormous overloads.
If there are no guides, you can try to drill without this equipment if you are confident in your abilities. However, it is strictly forbidden to change the drilling angle, as this can completely damage both the drill and the workpiece.
In no case should we forget about cooling and chip removal. The easiest way is to use soapy water, in which you should first dip the tip of the drill. Some experts recommend coating the drill vegetable oil or lard. This will significantly reduce the friction of the product on the metal and, as a result, will have a very positive effect on the cooling of the drill.
If we talk about extracting chips, then this must be done with regular frequency, periodically removing drilling waste. The easiest way is to turn the workpiece over so that the chips, under the influence of gravity, free the hole. If the product is very heavy, then improvised devices are used, including hooks or magnets. Otherwise, the chips can clog the grooves on the drill, which will subsequently lead to blocking of rotation, as well as to breakage of the drill.
Large diameter holes are the most difficult operation
Drill big hole in metal it is even more difficult than making a deep hole. There are several approaches: either use a conical drill to make a large-diameter hole in the metal in several approaches, or use a special crown. The cost of cone drills is very high, while the efficiency is lower than that of a crown.
That is why experts say that it is more correct to drill metal using a crown. In the central part there is a drill, while at the edges there is a cutting surface with sharply sharpened teeth. Thanks to the drill, the crown is fixed in one position and does not move during operation. Drilling is carried out at low speeds of the drill, and everything must be done very carefully and carefully so as not to damage the crown.
