- How the drill was tempered
- What is a household drill
- Drills for special purposes
- Hammer drill
- Drill for screwing fasteners
- Drill mixer
- Angle drill
- Choosing the right drill
- Power characteristics
- Drill design features and auxiliary systems
- The most important little things
It is difficult to choose a drill: many types, a lot of features, a lot of technical characteristics. If you don’t want to waste your money, then you have to delve into all this. I am sure that together we will cope, since we have already worked out some consumer tricks.
How the drill was tempered
Any master will say that the drill is the most important tool. Even those construction specialists who (seemingly) do not use it do not argue with this, although in fact, some mixers, electric screwdrivers, and screwdrivers are called drills by many manufacturers. Even rotary hammers can be safely considered the direct relatives of hole drilling machines. Hand drills working on muscle power (at least their real prototypes) have been known somewhere since the Renaissance, and the simplest devices for drilling work have been used for several thousand years and occupy their places of honor in many archaeological museums around the world..
It was possible to mechanize, or rather, electrify the process (steam drives had already taken place) at the end of the 19th century, then more or less compact electric motors appeared, which once again turned the world upside down. In 1889, Arthur James Arnot (future employee of the Black&Decker from Melbourne for the first time transmitted electrical energy to the drill, the task was to optimize the process of drilling stone and coal – so to speak, an industrial version. In 1895, the brothers Karl and Wilhelm Fein from Stuttgart distinguished themselves. They managed to create a drill that you can hold in your hands – a construction and household option. Two years later, AEG released the first production car similar to its modern counterparts. Further, almost nothing fundamentally changed, work was carried out only to improve the drill – ergonomics, productivity, safety, additional functions.
The first electric drill of the firm “Fine”, 1895.
Now, probably every man has a drill, well, at least almost all of us at least once, but thought about purchasing it. It is the best-selling instrument in any country in the world. Popular recognition is not at all accidental. The drill allows you to drill a variety of materials, drill with a blow, screw fasteners, clean and grind surfaces, mix inhomogeneous solutions, and cut threads. Some manufacturers offer a lot of special attachments that make it possible to use a drill as a jigsaw, milling cutter, planer … The usefulness of such functionality is very controversial, but there is a possibility itself, and it heats.
If earlier in our country the drill had to be “taken out”, now you just have to go to any specialized store or market, and you will see just a huge assortment. There are so many models and entire classes that not only amateurs at home, but also seasoned craftsmen can get lost in the instrumental variety – demand creates supply. Our common task is to understand all the nuances of electric drills, to make the selection process as conscious and comfortable as possible..
What is a household drill
Many are wondering about the “suitability” of a household tool. What are these cars that are several times cheaper than their older brothers? What is the difference? What are they for? Why do companies with near-space technology make simplified versions of their products? Everything is extremely simple: not everyone needs a drill to work with it around the clock, because there are people who have it peacefully resting in the closet / garage until you urgently need to hang a picture or repair a stool. Hobby class machines have been created for the home master. You shouldn’t include cheap Chinese brands and outright fakes here – often this is an unsuitable and unsafe tool for work. And, on the contrary, domestic units (some experts indiscriminately classify them as household units) are also not from this series – they are quite competitive in commercial use. The amateur class is a special line of tools or products of individual divisions of reputable world firms that are ready and able to make a special offer to a special consumer (in the context of “price / quality / functionality”).
Bosch PSB 500 RE
It may seem that the companies “choke” professional copies, but this is not entirely true, they create completely different machines. The main feature of household drills is that they can be operated no more than 4 hours a day, according to the “one to one” scheme (we work fifteen / twenty minutes, we rest the same amount). Why is that? A simple design, less durable materials, and weaker engines are usually used here. Professional drills have more powerful motors, wear-resistant parts, better protection against aggressive influences (dust, moisture, vibration). What do the developers of a household drill give us in return, in addition to a favorable price:
- Expanded functionality – as an illustration, a percussion tool, and even with a reverse (drill, drill, screw), for example, let’s take a Bosch PSB 500 RE. Professional machines have a much narrower specialization.
- Good ergonomics. We have a low weight due to the use of less powerful motors, the absence of a metal gear case, lightweight parts. The case is replete with soft inserts and overlays. The machine is supplied with a keyless chuck. Original product design (Black&Decker KR753).
- Protection from inexperienced users. Limited power performance and improved operator safety.
- Wide range of equipment. The case contains a set of drills, a spare chuck, a bit holder.
- Long warranty period. Some manufacturers offer 2 years instead of 1 for professional models.
Further, we will recall more than once the division of drills into “pro / hobby”, but for now, let’s summarize what has been said. A household tool definitely has a right to exist, it will perfectly cope with all tasks, provided that the loads are moderate. The commercial or amateur use of a particular drill is always indicated in the passport. Another reliable sign is the continuous operation of a professional drill (at least 45 minutes), and it must also withstand a work shift of at least 7-8 hours.
Drills for special purposes
A drill is a multifunctional tool in principle, but for the comfortable performance of specific tasks, some models are distinguished by a special design, a set of peculiar characteristics. Let’s take a closer look at them..
A hammer drill can help to drill into light concrete or masonry; for soft materials, the function is disabled. Let’s say right away that this is not a perforator: the impact power is ten times less here (joules are not even indicated in the manual) and the principle of the beating mechanism is different. In an impact drill, the main work is performed by a ratchet, consisting of gear couplings, which, under load, are disconnected (one of them slides off the other) and the shaft moves forward.
In the hammer drill, the blow is obtained from the work of a special “drunk” bearing and pneumatic elements. If the drilling function for a rock drill is the main one, then for a drill the hammer mode is just an auxiliary function. Firstly, it can only take light concrete and brick, and, secondly, such a mechanism serves for a very short time, and thirdly, other parameters of the tool suffer a little (the mass increases, there are spindle backlash, the accuracy of shockless drilling worsens).
The impact force of the drill and its resource directly depend on the pressure of the tool, on the strength and geometric characteristics of the gears, on the location of the ratchet (the further from the chuck, the weaker the drilling).
So, a hammer drill is a good solution for infrequent drilling operations “10 minutes a year”, an amateur option. These units will in no way replace a hammer drill, while the known versatility will have to pay off with a decrease in some standard characteristics. There are no rules without exception, impact drills can also be found in professional lines (Bosch GSB 16 RE, Makita HP2071).
Drill for screwing fasteners
Working with fasteners is one of the most important functions of a drill, you can clamp a bit and twist self-tapping screws into a cartridge of any of them, but some machines are better suited for this than others:
- The presence of a reverse is a very important point, since the screws have to be unscrewed from time to time during operation, fortunately, this function is available in almost all modern drills.
- Variable speed. It is impossible to work with self-tapping screws at high speed – it is necessary to lower. There are preset options, a sensitive button is used, a multi-position gearbox (multiple speeds).
- Pulse mode (short-term shocks). It is good for dismantling consumables.
- The removable chuck sometimes allows the bit shank to be installed directly into the spindle (Kress 650 BS). The dimensions of the machine are reduced, its weight is reduced.
- Torque adjustment. Such a function is considered very specific, it is characteristic of a tool that is allocated to a special class (screwdriver). Read more about cordless screwdrivers in the article “How to choose a cordless screwdriver”.
Kress 650 BS
Perhaps it is worth mentioning drills with automatic cassette self-tapping screws, a very convenient device for large-scale fastening work (for example, Makita 6844).
Many drills (if not talking about “clean” mixers with a rim cartridge) with a capacity of 1000 watts or more are capable of mixing viscous solutions. For such work, they are often assembled with extended auxiliary and D-shaped main handles (Makita 6300-4). In addition to this, the powerful drills have a multi-speed gearbox that allows downshifts with increasing torque (Bosch GRW 11 E). The high power of such machines and the presence of several protection systems make it possible to install large equipment in them: large-diameter drills, crowns (including for diamond drilling). Many of these drills have a breakaway sleeve that protects the worker and the machine from damage in case of jamming (Makita DBM080).
Bosch GRW 11 E
Usually these are lightweight compact machines designed to work in hard-to-reach places. They are equipped with an angular gear, so the spindle and accessories are located to the axis of the body at right angles (as in angle grinders), for example, Makita DA3011F. Otherwise, the angle drill does not have any special differences, well, except that their power is mostly low and the impact function cannot be. A real alternative to a highly specialized angle drill is the standard model angle bits for special tasks.
Choosing the right drill
On average, the power of drills is in the range of 500-900 watts, stronger machines also exist, but their lot is very large drilling or mixing of viscous solutions (Metabo B32 / 3 – 1.8 kW). We always mention that extra motor power affects the dimensions and weight of the product, but in the case of a drill, these moments are not so critical, unless, of course, it is purchased as a screwdriver. Only a sufficiently powerful power plant will be able to provide the necessary torque, the reserve of which is simply necessary for drilling large and deep holes, for frequent manipulations with durable materials.
Metabo B32 / 3
Spindle speed. The passports indicate the nominal idle speed, the higher it is, the cleaner the hole is and the more opportunities for a low-power tool (such a scheme is often used in household models). Also, it makes sense to select a high speed for an impact drill, and if the device will be periodically used for grinding / polishing. For work with fasteners – a high speed is not needed (400-500 rpm will fit), so you should definitely check the efficiency of the speed controllers.
Power / frequency / torque indicators are closely interconnected: when one of them changes, others inevitably change – you need to choose in a complex. Better yet, concentrate on the maximum tool diameters for different materials, these characteristics will tell much more eloquently about the tool..
Drill design features and auxiliary systems
Reversemakes it possible to unscrew the fasteners and release the stuck equipment. A checkbox, a through button or a 90 ° rotation of the brush unit (Metabo UHE 2850) relative to the collector (allows you to save power during reverse movement) changes the activation of the electric motor. A good reverse is close at hand and can be easily translated into various positions, but it is even better if it is associated with the start button so that there is no possibility of shifting when the engine is running. Ideal reversal provides equal torque in both directions (usually the twisting movement is much weaker).
Metabo UHE 2850
Multi-position gearboxdesigned to downshift and increase torque. First speed – low frequency and high torque, second / third speed – high frequency and low thrust. Obviously, machines with this design are much more functional than the rest, since when switching speeds, the output power does not change (Makita HP 2070).
Chuck characteristics.Basically, there are two types of chucks: key and keyless. The first type for changing the equipment will require the use of a special key, but it is reasonably considered more reliable, therefore it is used for powerful devices and impact drills.
Keyless chucks (BZP) are operated only by hand, no additional tool is needed here. The keyless chuck with one sleeve is tightened with one hand, it can be done even with gloves, it is used only with a spindle locking mechanism (push-button or automatically), for example, as in the Kress 850 SB-2 model. The two-sleeve chuck should be turned with both hands. BZP is a very convenient thing (you do not need to constantly look for an elusive key and tie it to a cord, your hands are not injured by the corrugation of the gear-crown mechanism), but sometimes users have complaints about their reliability and durability. High quality keyless chucks cost a lot of money, and sooner or later the chuck has to be changed.
Kress 850 SB-2
It is worth paying special attention to the maximum bore diameter of the chuck. The minimum is usually not limited (sometimes the cams converge almost to zero, more often to 1.5 mm), but there is always an upper limit. This is traditionally 10, 13 or 16 mm. Naturally, such restrictions depend on the power characteristics of the machine and are subject to them. The “ten” chuck is placed on a light tool, the 16th drill can only be pulled by a powerful drill, 13 – the diameter of the average.
Metal gear boxdirectly indicates that the instrument belongs to the professional class. Thanks to this design, heat is better removed from moving parts, high stability of the unit is ensured, although the weight of the drill will inevitably increase.
Electronic speed control.This is something different than permutation of gearbox speeds. In this case, using a thyristor or rheostat. Full-wave adjustment is provided by the degree of pressing the sensitive start key, press harder – higher speed. The rotational speed can be set in steps, for this a special wheel (Hitachi D10VC2) or a slide switch is used – this control is usually carried out on the body.
Note that when performing electronic adjustment, we limit the power output of the instrument, which does not happen with a mechanical preset..
Advanced models have frequency control system under load(constant electronics), thanks to which the machine monitors the load and maintains the set parameters due to the power reserves of the motor. It turns out that we can not only fine-tune the tool for a specific material, but also avoid jamming with a sharp change in density or an increase in pressure (AEG SB 22 2E).
AEG SB 22 2E
I have high-tech drills winding temperature sensors, which eliminates the possibility of damage to the motor during overloads. In critical cases, the power is automatically turned off or LED indication is triggered.
For powerful drills, it will be very relevant soft start system, which slowly accelerates the equipment to optimal speed (it is easier to start drilling exactly at the mark), excluding starting jerks (increases the durability of transmission elements) and overloading of electrical networks (AEG SB2E 1200 RST).
Pulse drillhelps to unscrew stuck fasteners, start drilling without punching, “defeat” too hard material. It is interesting that such a system works on the principle of a load jump, as with inrush currents (Metabo SBE 900 IMPULS). Using this function within reasonable limits will allow you to solve a number of complex problems, but it should be understood that in this mode the tool works extremely, the wear of the most important units increases.
Metabo SBE 900 IMPULS
Another point is the opportunity latching the power button when on(SPARKY BUR 150CET). What does it do? Firstly, while working, you can release the key and change the grip of the tool, just relax your hand. Secondly, only such drills can be installed permanently on a tripod or in a magnetic stand (Metabo B 7532/4), resulting in a lightweight drilling machine.
SPARKY BUR 150CET
The most important little things
- Choosing a specific model, it is not enough just to understand the technical characteristics of the tool, you also need to find exactly your own, the most convenient.
- We always recommend that you “shake” the machine thoroughly in your hands, paying particular attention to the configuration and type of handles, both main and auxiliary. Someone will like thin handles more, someone more voluminous. Feel the pads, it is better if they have a corrugation and a non-slip surface.
- Try to feel the weight distribution of the drill, there are very interesting options in this regard, for example, with a pistol grip shifted forward (DeWalt DWD215G).
- Be sure to evaluate the accessibility of all controls, their information content and ease of switching.
- Take a look at the length of the power cord and the material it is made of. Long soft cable will significantly increase the comfort when working “on site”.
- Check how well the chuck holds the drill, how easy / difficult it is to change, what is its real minimum and maximum (drill diameter).
- Feel the machine for spindle play.
- Run the drill in different modes, try to identify possible beats, noises, power losses under load.
- Pay attention to the possibility of a permanent installation. Typical tripod seat size is 43mm in diameter.
- Compare the packaging of competing products. Case, drills, metal depth gauge, spare chuck – all these things, if they are branded (!), Cost a lot.
Once again, I would like to say, choose the tool based on the predicted loads. Emphasize the maximum allowable rig size. Do not chase for additional gadgets “to be”. Keep in mind that only the part that is not in the structure does not break in the tool..