Small home repairs and large ones construction works can't do without a drill. Household and professional, impact, non-impact, angle, drill-mixers are used depending on the purpose of the work. Main parameter tool - power consumption, depends on it maximum number drill revolutions and additional features device. Therefore, before choosing a drill of a certain power, you should study the availability of functions that can greatly facilitate the work. The capabilities of a tool are determined not only by its cost, but also by its purpose: professional or household.
Features of household drills
A low-power tool (300-600 W) is used for drilling wood, metal, and plastic. It is not designed for long-term use and is used only occasionally in everyday life. It should be noted that drilling concrete walls can be an impossible job for such a tool, since hard surfaces require more force. As a rule, these are hammerless drills, with the help of which holes are made accurately and efficiently. In a household appliance, the drill is fixed in two ways:
- cam,
- quick-clamping
The design of the cartridge differs accordingly. In a cam drill, the drill is tightened using a wrench. It is inserted into a special socket, loosening the fastening or strengthening it with one or two turns. The keyless chuck does not use a key, so changing the drill is much faster. Such cartridges are made in two types:
- single-coupler,
- double coupling
The clutch is turned by hand, loosening or tightening the clamp. They work with a double-clutch chuck as follows: the first clutch is clamped by hand, and the second is unscrewed. The single-coupling chuck is installed only on models that have an automatic shaft locking function. Both types of chucks are quite reliable, but the master decides which drill to choose depending on the drill mount.
Fastening with a key is considered more reliable, but is suitable specifically for household use as a tool. Keyless chucks are made of steel or durable plastic, jaw chucks are made of steel.
Impact drill or hammer drill?
The performance of such a device is much higher than that of a non-impact device. Many buyers do not know the difference between an impact drill and a hammer drill. The drill operates simultaneously in 2 modes: rotary and reciprocating, which ensures the drill moves back and forth. Thus, the work is performed with greater force, which makes it possible to drill concrete walls of multi-story buildings. However, the device may overheat, so you should monitor the motor during operation, giving it a rest to cool down.
Due to more simple device impact mechanism, it should be noted that the impact amplitude is small compared to a hammer drill. The latter has a special pneumatic impact, quickly drills through the most durable materials, for example, brick, reinforced concrete. The hammer drill operates without overheating for a long time; it can be used daily for several hours. If there is a hammer drill in the house, then you can avoid buying simple tool, if you purchase an adapter for it for regular drills.
For everyday use, an impact drill has advantages over a hammer drill. It is lighter, rarely used, so there is no point in overpaying for professional tool. And yet, if you need an impact drill, how to choose the most suitable model? The minimum set of required functions is as follows:
- shock shutdown function,
- rotation speed adjustment,
- fixing the trigger in a certain position.
The standard power is 400-1200 W, and the higher it is, the faster and easier the work is done. For home use optimal solution will be a purchase impact drill power 700 W. For frequent household work, it is enough to purchase a device with a power of up to 1000 W.
Why do you need an angle drill?
Another type of tool is an angle drill. They are used in confined spaces where regular drill will not allow you to work comfortably. A feature of such models is the ability to drill at an angle, since the chuck is attached at an angle of 90º, that is, in the shape of the letter G. Thus, drilling is carried out in hard-to-reach places, for example, under the hood of a car or when assembling furniture.
Drill mixers
The tool is used for drilling and kneading mortar, glue or mixing color with paint. The drill-mixer features an additional low-speed operating mode and a set of attachments. Depending on the model, these attachments can be attached in the amount of one or two pieces. The mixers also have reverse motion, and increased power guarantees protection against overheating. They are used to drill into soft building materials, as they do not have an impact function.
When choosing a tool, pay attention to the maximum diameter of the mixer, which is usually 120 mm. It should be noted that the device is usually designed for mixing up to about 20 liters of solution, glue, and paint. It is not advisable to use it for mixing concrete in large quantities. For such volumes of work, it is better to purchase a concrete mixer.
Drill/driver
In addition to drilling, they are used for tightening self-tapping screws, screws. It operates in 2 modes, is small in size, and has low power. Great for assembling furniture, when you need to make a hole and tighten the screws. It may be the only drilling tool in the house if it is not used for concrete surface for a long time.
Professional tool
Required when frequent use, for example, on a construction site. Has increased permissible load and a large permitted drill diameter. Equipped with the most powerful motors for continuous operation without overheating for hours. That is why they have a lot of weight, which is also taken into account when purchasing, since your hands quickly get tired while drilling.
All drills are powered by electricity or a battery. The use of the latter does not mean low power of the device. Modern lithium ion batteries provide work for a longer time than nickel-cadmium batteries. Mains power provides comfort, but remains dependent on the location of the outlet, cable length, and the presence of an extension cord.
So, when choosing a drill, take into account the frequency of its use and the approximate amount of work. The number of revolutions is also an important characteristic: the higher the number, the better the performance of the tool. It should be noted that even low-power household drills can provide sufficient shaft rotation speed. It all depends on the material of the surface for which it is used.
When choosing a tool for drilling, a specialist faces two tasks: to maximize the service life of the tool, and also to achieve the specified hole quality parameters. Holes can be obtained different ways: stamping, casting, forging, laser or burning; in metalworking, drilling is most often used, and, if necessary, reaming and boring. Whatever the chain of operations, the accuracy of the hole is usually determined by one or more geometric parameters: straightness (parallelism and perpendicularity of the axes), true position, cylindricity (roundness, cone-shaped, barrel-shaped), surface roughness level.
Exist various factors which may lead to unsatisfactory results. The choice of drill bit and how it will be applied is critical to the accuracy of the hole. Traditional drills from high speed steel do not give the best results at high speed modes. Cobalt is a little harder and more wear resistant and can achieve better results. Then comes powdered carbide and finally hard carbide, which, with the exception of gun drilling, provides best result for all parameters of determining surface quality. Surface roughness Ra of 0.32 µm or less is easily achieved with carbide drills, provided that the installation is rigid, there is no runout in the drill and tool holder, the use of high-quality coolant, and the selection of appropriate speed and feed.
To improve hole quality and increase tool life, special drills should be used rather than drill bits general purpose. Many manufacturers offer series of drills designed to handle a specific material, to drill to a specific depth, with improved chip control, etc.
When working on CNC lathes, you should pay attention to drills with replaceable inserts. In some cases, such drills are used for rough drilling, then the tool is moved a short distance along the X axis and then the drill is used as a boring bar. Thus, a smaller range of tools is required, you can save time and get a straight and precise hole in size, with low cleanliness requirements. In this case, it is better to give preference to drills with a special chip breaker, which will allow the formation of chips of the required shape. Boring special tool, of course, will allow you to achieve high hole characteristics - you can easily change the radius, properties cutting edge, feed rate, thus boring provides good control. But such processing will require additional time, which significantly lengthens the entire process.
Regardless of whether boring is required or not, drilling should be carried out with a high-quality coolant at the appropriate concentration - this will ultimately improve surface quality, increase tool life, and make the machining process more predictable. Exist different kinds Coolant - it can be an emulsion in an aqueous solution, or a solution of mineral and synthetic oils, the choice depends on the type of material being processed.
It is also important to pay attention to the tool holder. No matter what type of tool or what brand of tool you use, after an average of four years, wear and tear will begin to affect its performance.
Even with the best holders and new carbide drills, reaming often remains the best way achieve all specified requirements. Perhaps, the best option will use a reamer with replaceable plates, which will allow achieving maximum productivity with at the lowest cost. These reamers are more economical than solid blades and can provide high quality surfaces at feed speeds up to 7500 mm/min.
Bores need very precise alignment, much more precise than drills and reamers. Product manager for Iscar Canada, David Vetresin, says hydraulic holders, and in some cases thermal clamps, are the best choice to keep the spindle from being damaged by operating shocks. About 80% of hole quality problems are due to poor alignment. Even with the best tool and holders, when installed in a machining center with a runout of 0.002 mm on the spindle, we obtain an error at the end of the reamer of 0.05 mm. This is why it is necessary to use custom holders. They have radial and angular adjustment screws, and with their help it is possible to achieve runout of up to 0.001 mm or less.
When working on CNC lathes, the turret and spindle must also be perfectly aligned, otherwise you will need a reamer with a floating holder that allows it to self-center. But they cannot be used for high-feed work with reamers with replaceable inserts or replaceable heads; they can only be used with solid carbide or high-speed steel tools.
Even more effective is processing without drilling and boring operations, performed with just a drill. For example, there are drills equipped with special plates for polishing the surface during the cutting process, and a self-centering tip that prevents the tool from moving.
One of the most complex tasks In drilling is the processing of superalloys based on nickel and cobalt, the problems of chip evacuation and heat generation arise here even more acutely. Due to the poor heat transfer properties and high hardness of these materials, it is worth using drills with indexable inserts operating at significantly reduced speeds and feeds, but not too low so as to encounter problems with metal hardening. Those. it is necessary to select a feed rate to find a balance between drill breakage and the formation of cracks and subsequent destruction of the material. At the same time, the tool life is about a quarter compared to similar work when machining alloy steel, so replacing inserts will be much more cost-effective compared to replacing an entire drill. In addition, since these materials tend to harden quickly, it is important to ensure that a sufficient volume of coolant is supplied to the high pressure, and the shape of the chips must be such that they can easily pass through the flutes of the drill. Retraction of the drill to remove chips or pauses during the drilling process should be avoided. For the same reason, it is recommended to select a process without drilling a preliminary hole.
When processing superalloys, the method of fastening the tool is of great importance, and here, too, preference is given to hydraulic chucks, which provide a higher clamping force than collet chucks. In addition, the oil contained within this holder provides some additional vibration dampening, and with this kind of drilling, any advantage is of great importance.
Particularly difficult is drilling small holes with a diameter of less than 3mm. Drills for processing such holes are called micro drills. The coolant used with such drills should be of very low viscosity, preferably at water based. Micro-drilling is expensive. To avoid drill breakage, a low feed rate is required, and it is also necessary to achieve sufficient spindle rotation. All this causes a decrease in productivity and leads to increased costs, not to mention the high cost of the micro drills themselves.
As an alternative, in certain diameters and lengths, cobalt and powder metal micro drills can be used, which will be three times less expensive.
If the size of the required micro drill is not included in the manufacturer's standard line, boring and other secondary operations will be very expensive. In cases where quite a lot of such drills are required, it will be more cost-effective to order individually manufactured micro-drills.
In everyday life, situations often arise in which it is necessary to apply male strength and skills. Drilling a hole in the wall, screwing in a few screws, making repairs in a room, or assembling a simple structure on a summer cottage can be done by anyone with the appropriate tools. Drill is an indispensable assistant to solve such problems. Moreover, if it is not planned professional use equipment, simple, inexpensive models are also suitable, the choice of which is very wide.
For many buyers, the determining factor when choosing is the cost of the tool. But purchasing cheap Chinese models is not a rational investment, since the equipment can quickly break down and require repair or replacement. The price of the product should be an important, but not the only factor when choosing. The following parameters must be taken into account:
- Drill power and energy consumption. There are models on the market that require from 300 to 1500 watts to operate.
- Maximum chuck rotation speed. Based on this parameter, you can determine the suitability of the drill for working with various materials and nozzles.
- The presence of a reverse system and speed regulator, making the operation of the equipment more convenient and functional.
- The maximum permissible diameter of holes for the preparation of which a drill can be used.
- The presence of a rotation lock button, which also expands the capabilities of the tool.
- Type of fastening of nozzles in the chuck: using a special key or quick-clamping.
The first thing that attracts attention is the power of the drill. If you plan to purchase a household model for home use, a 500 Watt option is suitable. For frequent use and preparation of holes in concrete, brick, and other materials of increased hardness, it is necessary to choose a more powerful tool. You can only purchase 300-400 watt drills if you have strong financial restrictions.
The rotation speed of the cartridge also differs different models and tool brands. For household use a rational choice would be equipment that produces 3000 rpm. Working with hard surfaces, especially when using an impact mechanism, requires higher rotation speeds of the chuck. It is advisable to purchase a drill with a speed controller, which allows you to customize the tool for a specific material.
It is also necessary to select equipment based on the maximum permissible hole diameter. If the equipment is not designed for drilling large holes, the likely outcome is damage to the electric motor. If you plan to operate the equipment as an element grinding machine, mixer, other equipment, the presence of a rotation lock button is considered prerequisite at the time of buying.
As additional criterion the type of cartridge is considered. The quick-clamping option is considered more convenient, but such a tool is somewhat more expensive. Cartridges with a single-case mechanism are easier to use. Rotary hammers are equipped with two-sleeve devices. For home use, models are suitable whose attachments are clamped with a special key.
Tool classification
When choosing a drill, in addition to the above parameters, it is necessary to take into account the intensity and frequency of its use, without going to extremes. Purchasing expensive professional model, designed for daily use for several hours, is not rational. The equipment will remain idle for most of its life. If you buy simple model and start making money by renovating premises, very quickly such a product will have to be replaced with a new one.
The market offers several options for tools for home use. The simplest and most inexpensive are considered electric drills. Low weight and dimensions, ease of use, and minimal energy consumption are considered the main advantages of such equipment.
For owners of apartments and private houses made of concrete slabs, brick and others durable materials A rational investment would be to purchase a hammer drill. Great power and dimensions, the presence of an impact function makes the tool an indispensable assistant when drilling holes in walls. An intermediate option is to buy an impact drill. It is quite convenient to work with such equipment, and in terms of functionality it is only slightly inferior to rotary hammers.
In accordance with the generally accepted classification, drills are divided into the following types:
- Standard drills, the most common and in demand.
- Angled models, the use of which allows you to work in hard-to-reach places.
- Mixer-type equipment capable of not only drilling, but also working with various attachments for mixing materials.
- Compact and lightweight screwdrivers, with network connection alternating current or battery models.
- Rotary hammers equipped with a special gearbox and impact mechanisms of similar design.
These options are considered basic for use at home. If necessary, you can purchase specialized models, for example, a pneumatic device, magnetic or electrical discharge equipment, equipment for drilling holes in printed circuit boards. Such equipment is not used for domestic needs, and its purchase is justified if a person is engaged in similar works at home.
Advantages and distinctive features of various types of drills
Standard electric drill
A standard electric drill has a fairly simple design, in which power unit drives the chuck into rotation through a gearbox. Similar design explains the advantages of the model, namely compact size, light weight, and the ability to operate the tool with one hand. There are many models and brands of this equipment, differing in power, rotation speed and other characteristics.
Hammer drill
An impact drill is considered a higher-level tool and allows you to work with materials that are inaccessible to simple equipment. Make a hole in concrete wall a conventional tool will not succeed, while the impact mechanism is able to successfully cope with the task.
The difference between the equipment is special mechanism, giving the cartridge pushing movements in addition to rotational ones. In almost all models, such a function is controllable, and its presence significantly increases the functionality of the equipment. Structural diagram does not have elements typical of rotary hammers, but at the household level few people ask this question. For typical tasks In housekeeping, such a mechanism is considered a rational investment.
Angle drill
In some cases, it becomes necessary to drill holes in hard-to-reach places where working with a standard tool is impossible. An angle drill helps solve the problem. Its feature is original design gearbox located perpendicular to the housing. As a result, it becomes possible to drill holes at any angle. Such a tool is rarely purchased, but in some cases it is an indispensable device.
Drills and screwdrivers
Models that combine the functions of a drill and a screwdriver are considered very popular. In addition to traditional operations for preparing holes, it is convenient to use the tool for assembling furniture, construction and repair work. The presence of two speeds of rotation of the cartridge. And also smooth adjustment due to changing the force on the start button distinguishes such models from other types of tools. The presence of a reverse function is considered mandatory.
Cordless drills
Cordless drills deserve special mention. The tool is mobile and very easy to use due to the absence of wires and the need to have an outlet or extension cord on hand. If you purchase a drill to work outdoors, or in a room without power supply, this option is rational. It is best to buy a tool with a lithium-ion battery that does not lose performance during long periods of inactivity. If you plan to use the equipment intensively, cheap models with a nickel-cadmium battery are suitable.
Mandatory parameters that you need to pay attention to are the battery voltage and its capacity. In most cases, mechanisms powered by 18 V sources provide greater torque than their 96 V counterparts. The duration of use of the drill without recharging depends on the battery capacity.
What to look for when choosing
Despite the abundance of choice in stores, purchasing quality and at the same time inexpensive model Difficult for home use. To do this, it is necessary to consider the maximum possible number of electric drills available. price segment. Compare characteristics, read reviews from owners.
The main criteria that must be adhered to are:
- The type of material for which the tool is purchased. To drill concrete, you need an impact mechanism or a hammer drill. A simple drill is suitable for working with wood, plastic or drywall.
- If the choice is between impact model or a hammer drill, it is also necessary to evaluate the hardness of the surface being treated. For drilling concrete, chipping walls and other heavy tasks, it is better to go with the second option.
- If you need to drill holes exclusively, it is important to focus on the rotation speed of the chuck, which should be at least 3000 rpm. If you plan to use the tool as a screwdriver, there is an adjustable rotation speed and a reverse mechanism.
- The equipment should be easy to use, fit well in the hand, and preferably have low weight and dimensions. These criteria significantly affect the speed and quality of work.
- The existing cable should allow you to use the tool without any difficulties, which is ensured by a sufficient length of the wire. A drill with a short cable is inconvenient, which results in constant connection through an extension cord.
- It is best to purchase products from well-known world brands that have proven themselves in the market. Unknown brands of equipment mean you risk getting a low-quality tool with minimal service life.
- The cost of the product also matters. If the drill will be used constantly, it is advisable not to save money and purchase high-quality equipment.
In addition to the specified criteria, the presence of a manufacturer's warranty is checked. In this case, the buyer protects himself from purchasing counterfeits or low-quality products. By following these recommendations, you can be confident in the performance of the electric drill, the suitability of the tool for everyday tasks, its reliability and durability.
29. Drilling. The essence of the process, purpose and scope of application, equipment used (machine), tools, fixtures, dimensional accuracy and roughness of the processed surface.
Drilling- the main method of producing through and blind holes in solid workpiece material. As tool used drill. Processing is carried out on drilling and turning machines. On drilling machines, the drill makes a rotational and longitudinal movement along the axis of the hole, and the workpiece is fixed on the machine table. On lathes, the workpiece is fixed in a chuck and makes a rotational movement, the drill is attached to the tailstock of the machine and makes a translational movement along the axis of the hole.
Fig.2. Schemes: a, b - drilling, c - reaming, d - countersinking, d - reaming
The diameter of the hole being drilled can be increased with a larger drill. Such operations are called drilling. When drilling, relatively low accuracy and surface quality are ensured.
To obtain holes of higher accuracy and lower surface roughness, countersinking and reaming are performed. Countersinking process pre-made holes with a multi-blade tool countersink, which has a more rigid working part. The number of teeth is at least three.
Deployment You can correct inaccuracies in the shape of the hole. Sweeps- a multi-blade tool that cuts very thin layers from the surface being processed.
Drilling purpose: Drilling is a necessary operation for obtaining holes in various materials during their processing, the purpose of which is:
Making holes for thread cutting, countersinking, reaming or boring.
Making holes (technological) for placement in them electrical cables, anchor bolts, fastening elements, etc.
Separating (cutting) blanks from sheets of material.
Weakening of destructible structures.
Laying an explosive charge during the extraction of natural stone.
Drilling operations are performed on the following machines:
Vertical drilling machines.
Horizontal drilling machines.
Vertical boring machines.
Horizontal boring machines.
Vertical milling machines.
Horizontal milling machines.
Universal milling machines.
Lathes (the drill is stationary and the workpiece rotates).
Backing lathes (drilling is an auxiliary operation, the drill is stationary).
To facilitate the processes of cutting materials, use the following:
Cooling (water, emulsions, oleic acid, carbon dioxide, graphite).
Ultrasound (ultrasonic drill vibrations increase productivity and chip crushing).
Heating (weaken the hardness of difficult-to-cut materials).
Impact (during impact-rotary drilling (drilling) of stone, concrete).
30. Reaching out. The essence of the process, purpose and scope of application, equipment used (machine), tools, fixtures, dimensional accuracy and roughness of the processed surface.
Reaching out- a high-performance method of processing parts of various shapes, providing high accuracy of shape and size treated surface. Due to the high cost tool - broach, broaching is used in large-scale production. In broaching, each cutting tooth is larger than the next one by a certain amount. The cutting process when broaching is carried out on broaching vertical and horizontal versions of machines at forward movement tool relative to a stationary workpiece in one pass.
Holes of various geometric shapes are drawn on horizontal broaching machines for internal broaching. Hole sizes from 5 to 250 mm.
Rice. 6. Broaching schemes: 1 – workpiece, 2 – broaching; a...d - internal pulling; z...g - external pulling
Cylindrical holes are drawn after drilling, boring or countersinking. Key and spline grooves are pulled through with broaches, the shape of which in cross section corresponds to the profile of the hole being pulled.
External surfaces of various geometric shapes are drawn on vertical broaching machines for external broaching.
Broaching is used in large-scale and mass production of metal products, and rarely in small-scale and individual production. Broaches of various designs - external, internal, and mandrels - are one of the most expensive tools for metalworking. Sometimes each broach during its manufacture requires the highest precision and correct calculation. This is due to the fact that the tool, when broaching, operates under the most difficult and severe conditions of enormous loads (tension, compression, bending, abrasive and adhesive chipping of the broach blades). Broaching is preceded by preparatory metalworking operations, such as drilling, countersinking, reaming, cutting (i.e., broaching requires a fairly accurately machined surface of the workpiece).
Burnishing(mandreling) is a type of processing of workpieces without removing chips. The essence of mandrel boils down to the movement of a rigid tool, a mandrel, in the hole of the workpiece under tension. The cross-sectional dimensions of the tool are larger than the cross-sectional dimensions of the workpiece hole by the amount of interference.
Broaching machines:
Horizontal broaching machines: All types of internal and external broaching of workpieces.
Press: Processing holes with mandrels (firmware, shaping, calibration).
Types of broaching:
Internal pulling. External pulling. Burnishing. Incandescent.
Ratchet(Fig. 155) is used for drilling holes with a diameter of up to 19-30 mm in hard-to-reach places.
The ratchet consists of a spindle 1, which is covered by a handle fork 2. A ratchet wheel 3 with teeth directed in one direction is attached to the spindle. At one end of the spindle there is a hole for fastening the drill, and at the other a high faceted nut 4 is screwed on, with a conical freely rotating stop 5. A pawl 6 is hinged in the fork of the handle, which, under the action of the spring 7, slides into the spaces between the teeth of the ratchet wheel. When the handle is turned clockwise, the pawl rotates the spindle through the ratchet wheel, and with it the fixed drill. The tall nut is screwed off the spindle and, resting against a fixed support or bracket, creates the necessary feed pressure on the drill, which, being pressed into the product, drills a hole in it. When the handle is turned in the opposite direction, the pawl slides along the teeth of the ratchet and the spindle remains motionless.
The ratchet works as follows. Use the handle to rotate the spindle clockwise 1/4 turn and then move it back. The ratchet handle is made long enough (300-400 mm) to ease the effort during the working movement.
The rate of operation of the ratchet is 6-8 revolutions of the drill per minute. The feed rate per revolution of the drill is about 0.1 mm.
Despite the slow pace of work, ratchets are widely used, as they make it possible to drill holes of large diameters and in places where other drilling devices cannot be used.
Kolovorot - the simplest device for drilling holes. It is used for drilling small holes in wood, fiber and soft metals, for screwing and unscrewing screws and screws, lapping valves, etc.
The rotor (Fig. 156) consists of a curved steel rod, at the upper end of which there is a freely rotating thrust cap, and at the lower end a cartridge is fixed. A wooden handle freely rotating around its axis is placed on the knee.
The work with the brace is carried out as follows: the head is pressed with the left hand or chest and this creates a force for feeding the drill, and right hand rotate the rotary handle.
A screw drill (Fig. 157) is used for drilling holes with a diameter of no more than 3 mm; it consists of a spindle with a four-start thread on the rod, along which the nut moves freely. A handle is placed on the upper end of the spindle, in which the end of the spindle rotates freely, and a head or chuck is attached to the lower end, in which the drill is clamped. If you apply pressure on the handle with your left hand, and move the threaded nut up and down with your right hand, the spindle and drill will rotate in one direction or the other and drill the product. In this case, double-sided feather drills are used.
If you install a spiral spring under the nut in the same drill, and attach a handwheel to the bottom of the spindle, then the rotation of the spindle when moving the nut down and up will occur only in one direction.
This is done as follows: the nut is moved quickly down, then released from the hand; then, under the action of a compressed spring, rotating, it rises up the thread of the spindle, and at this time the handwheel, under the influence of inertial force, continues to rotate the spindle in the same direction; then the nut is quickly lowered down again and thereby accelerates the rotation of the spindle and drill. Thanks to this device, a screw drill can use single-sided tip or twist drills, which make drilling much easier.
Hand drill with gear drive (Fig. 158) is used for drilling holes with a diameter of up to 8 mm,
The drill consists of a body 1, a chest plate 2, a handle 3, a spindle 4, a self-centering three-jaw chuck 5 and a handle 6 for holding the drill while drilling.
The spindle is driven into rotation by a pair of bevel gears 7 and 8 using a handle 3. The spindle has two speeds, which are changed by a cam clutch 9.
Drilling technique hand drill consists of the following: the drill is clamped in the chuck, holding the drill by the handle 6 with your left hand, and installing the drill in the place intended for drilling. Then they press the plate 2 with their chest and rotate the handle 3 with their right hand. When the handle rotates, the movement is transmitted through the bevel gears to the drill.
During the drilling process, it is necessary to ensure that the drill is accurately directed along the axis of the hole, and that the axis of the drill coincides with the axis of the drill.
A drill with a gear drive makes up to 300 rpm.
Pneumatic drill(Fig. 159) is designed so that the rotation of the drill is carried out using compressed (up to 5 atm) air and can only be used in those workshops that have compressor unit for getting compressed air. Hand-held pneumatic drills are available in different sizes, weights and power and are designed for drilling holes with a diameter of up to 50 mm, driving screws, bolts, nuts and performing other work. Depending on the amount of air supplied to the drill body, the number of revolutions of the drill is adjusted within the range of 50-2500 per minute.
Compressed air through a rubber hose connected to nipple 1 enters the drill body and, due to its action on the spools and pistons, causes the drill to rotate.
The air supply is regulated by turning knob 2 around its axis.
The force on the drill is produced either by turning the handwheel 3, which, with its freely rotating center, rests against a fixed support (bracket), or - in small drills - by pressing with the chest according to the principle of a drill with a gear drive.
When working with a pneumatic drill, especially when pressing the drill with your hands or chest (without the help of a bracket), you should carefully monitor the rotation of the spindle and if its movement slows down, immediately turn off the drill.
Electric drill(Fig. 160) - the most common device for drilling holes in metalwork workshops, it is gradually replacing existing drills and ratchets.
An electric drill, or electric drill, has a small electric motor placed in an aluminum housing 1. A chuck 2 is attached to the end of the electric motor shaft, in which the drill is clamped. The mechanic holds the drill in use with both hands by the handles 3, rigidly connected to the body, and sets it so that the center of the drill exactly coincides with the center of the future hole marked with a center punch; then he presses with his chest a special stop 4 located in the upper part of the body, and with a button placed in box 5, turns on the motor. The electric drill can operate on a regular electrical outlet with a voltage of 120 or 220 volts.
The speed of the electric drill drill is 1000-1200 per minute. Depending on the design and power of the motor, an electric drill can drill holes with a diameter of 2 to 25 mm.
Electric drills are used in cases where the product cannot be placed on drilling machine or when it is necessary to drill a hole without removing parts from the machine.