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 versatile tool requires some skill in working with hard work. 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 electric drill. 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 the 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.
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 and give it correct position, as well as provide 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 breakage of the drill and also reduce the formation of burrs on the exit edge 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. 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.
Drilling large holes is not a problem if you choose the right tool. For example, such work may be necessary to secure a channel or metal corner. The easiest way is to use an electric drill, but getting a hole with a diameter of, for example, 15 mm requires a lot of effort. To drill a large diameter hole in metal, use special devices and core drilling technology.
Features of creation
When drilling, it must be taken into account that the crown or stepped cone nozzle must be selected in such a way that it has a smaller diameter than the hole being created.
When using different tools, it is also necessary to take into account their features. For example, when drilling with conical products, smooth edges are obtained.
Drill accessories
There are several accessories for drills that can make the process easier and make big hole even:
- Drilling jig. This device is a housing in which there are several guide bushings for drills different diameters. The material used to create the bushings is harder than drill bits, so you don't have to worry about the tool moving to the side while drilling and widening the hole.
- Drill guide. This product allows you to fix the tool in such a way that it does not deviate to the side during drilling. If such a product is not available, the tool may move to the side, resulting in an uneven edge. It can also be mounted at an angle. But when drilling metal products, this is usually not required.
- Drill stand. A DIY product like this can be an inexpensive replacement for a drilling machine, as it allows you to carry out work more comfortably. When using a stand, a fixed tool moves along the bar using a lever. In this case, displacement is completely eliminated, since the workpiece being drilled is securely held due to the presence of a clamp.
Using these products, you can greatly facilitate the process of drilling metal products.
Feature of deep holes
To drill a deep hole in metal, it is best to use lathe. Cooling must be done during this process. In this case, the chips must be forcibly removed. Periodically, the tool is removed from the workpiece to remove chips.
When working without specialized devices, you should not recess the nozzle more than 2/3 of its length. Water must be used for cooling during operation. If the work is done in several approaches, changing the angle is not allowed.
Features of large diameter holes
This procedure is more complex than deep drilling. Cutting work is carried out either using a crown or using a cone drill. Crowns for metal are similar to products for concrete and drywall. The only difference is the material used to create the cutting edge.
Drilling can also be carried out with standard products in several stages. To do this, first use a nozzle of small diameter. Then a larger tool is selected.
Most in a convenient way is the use of cone drills. Such devices allow you to drill a large hole in one go. To do this, the tool is simply recessed into the material.
Hassle-free drilling
During work, you can use a small section nozzle, as well as a used grinding wheel for an angle grinder. It is important to remember that it should have a smaller diameter than the hole being created.
Before carrying out work, a circle for the hole is marked on the workpiece, and the second circle will be smaller than the first by a distance equal to the diameter of the drill used. After this, 2 holes are marked in opposite places of the circle. It is necessary to retreat 3 mm from them and mark the places for drilling. Thus, drilling occurs along the entire drawn circle. If additional work is necessary, some areas will have to be processed with a chisel. This will create jagged edges that will then need to be filed down. It is important to ensure that during work the circumference does not increase, i.e. do not expand the planned diameter.
Cone drill
The described types of drills are made from tool steel. The shanks of such products can be hexagonal or cylindrical. Cutting edge removes all burrs, so the edge is smooth. The end of the drill head has a sharpened point that allows pre-drilling of the material.
Using these products you can:
- create cuts with a diameter of up to 30 mm;
- forget about jagged edges;
- carry out boring of various diameters without changing the nozzle.
Thanks to step drills, you can create cuts of various diameters in sheet steel up to 4 mm thick. Unlike a simple cone drill, when using such products drilled diameter is fixed.
The disadvantages include:
- the need to use tools with low speeds and high torque;
- sensitivity even to small distortions.
Despite these disadvantages, this attachment allows you to conveniently work with metal plates, quickly drilling circles required diameter.
Metal crown
Metal processing is complex process, therefore such work is usually carried out using specialized equipment. To carry out work at home, you can use core drills.
Such products allow you to make the edges round and centered. In this case, a standard drill is used for drilling. The products consist of several parts:
- crown;
- centering attachment;
- product shank;
- screws that are necessary for fastening.
When using a core drill, the speed of work increases up to 10 times. Another advantage is the ability to accurately drill in the range from 1.2 to 15 cm.
In this case, there is no need to perform alignment during drilling. It is also worth noting that such drills have higher wear resistance compared to twist drills.
Before starting work, a centering drill is installed in the center of the circle, after which drilling is carried out. After this, the drill is retracted and the work is carried out with a crown.
Hole press
One of the common methods is punching using a special press. It happens like this:
- First, the workpiece is placed on the press table and grabbed by several clamps.
- The metal is then moved under the punching tool. At this stage, additional fastening of the material occurs using a clamping ring.
- On last stage and penetration occurs using a punch.
The revolver can have several nozzles of different diameters, which allows you to quickly create holes of different diameters. Such equipment is usually not used for working with metal in domestic conditions.
If you plan to do the work at home, you should choose a universal tool. This will allow you to easily process metal without worrying about purchasing additional details. The video presented will introduce you in detail to the technology of the process.
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 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 also, 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 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. Index correct mode- beautiful, long shavings.
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 at different diameters drill bits and carbon steel drilling
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 with a large number of 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 spoons machine oil, you can use the waste one and boil the solution until a soapy, homogeneous 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 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 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:
- 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 carbide with additives and operated 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.
All photos from the article
If you need to make a large diameter hole in a tree, you will have to use special devices, each of which has its own characteristics. We'll look at everything possible options and we will tell you about their main advantages and disadvantages so that you can choose best option in accordance with the specifics of work in a given situation.
Criteria for choosing a quality option
Below we will look at the main types of devices, but for now we will outline the criteria that any option must meet, regardless of its modification:
| Reliable manufacturing material | Of course, it is unlikely that you can determine this criterion by eye, so it is best to ask the seller for a quality certificate for the product. Unreliable counterfeit versions from China most often do not have any documents. |
| High quality performance | Examine the product carefully: the surface must be smooth without flaws or defects, the cutting part must be carefully sharpened. If you are purchasing a wood drill long length– check whether it is even, this can be done by eye or by rolling it on a flat surface – any irregularities on it are immediately visible. |
| Good packaging | Low-quality fakes are most often packaged haphazardly, moreover, there are mistakes in the words. No one famous brand will not allow yourself unsightly packaging, remember this. |
| Price | Price is also an indicator of quality, usually the most budget options short-lived, especially when it comes to large drills and fixtures. After all, they are very exposed high loads in progress. |
Advice! To be sure to purchase quality product, be it, you need to contact the official representatives of a particular brand or buy products from well-known stores that care about their reputation and do not sell cheap fakes.
