Screwdriver (Cordless Drill) – irreplaceable thing in the construction, home repair, as well as on any production. It will save a lot of time if we have to use a screwdriver. Suitable for all types of tightening screws, even nuts and bolts, metal drilling, plastic, wood. How to select this tool, what to look for?
Each cordless drill has a number of characteristics:
- maximum torque;
- battery Type;
- corded or battery;
- professional or consumer.
Maximum torque (force). This is one of the most important characteristics of any cordless drill, it determines how large the diameter of the screw can be wrapped in wood, metal, and others. For the majority of domestic use often enough 10-12 N / m (Newton-meter) of torque. With this power you can spin the most self-tapping screws, be it wood, metal, 1/8 “, measuring about 3 1/2”. You can also drill a hole in a tree 7/16 “without problems, metal (about 5/16”). This is 90% of household chores. If you want to close the roof when you have to use the roofing screws, it is advisable to use a screwdriver with a torque of 20 N / m or more, because the roofing screw diameter is large enough. Thus it is possible to make a hole in the brick. At low power cordless drill when such works will immediately sit down battery.
Battery Type. Most consumer grade cordless drills equipped with Ni-Cd (nickel-cadmium) batteries. This is able to survive up to 1000 chargings, at the end of battery life, its capacity is almost at zero, it is very quickly discharged, then it must be replaced with a new one. This type of battery, it is desirable to discharge fully before you charge again, with incomplete discharge may decrease battery capacity, which could result in the accelerated replacement. This is a very big disadvantage Ni-Cd batteries. But the price is significantly lower than for domestic purposes is probably the best choice.
Li-Ion battery type. This can be recharged at any time, not necessarily completely discharged as a Ni-Cd battery, but the cost is much higher.
Any battery, regardless of whether you use them or not, gradually loses its capacity. If you buy a cordless drill for home, consider whether you dear Li-ion battery is needed, or quite inexpensive Ni-Cd. About 3 years later still have to change, perhaps most of the time it just will lie on your shelf, losing capacity. If you are working intensively, you can stay at the choice of Li-Ion.
Battery cost is a major part of the cost of the cordless drill, it can reach 80%. Very often it happens that it’s easier to buy a new cordless drill than a spare battery to it.
Another important point to take two or with one battery? If you work from case to case and can be taken with one. If on the contrary quite intensively, it is better to take two batteries, as to buy separately get much more expensive. One use, the second at this point is on charge. When buying pay attention to the date of manufacture of the product, it is desirable that the battery was not old, at least this year, not one and a half or two years.
Mains or battery? Advantages of the battery in the course of its mobility, it is possible to work in any place where there is no electricity network, independently of the electrical cord. The disadvantage – price. At the same characteristics of the difference in price – in 1.5 times or more.
If there is a source of electricity, it is quite possible to get a network cordless drill, essentially the same thing. Of course the big drawback – the inability to work in the “field” is probably the only one, but do not have time to spend money on replacement batteries.
Professional or home. There are 2 main differences. First, this torque. A professional it is significantly higher, about 30N / m, which is three times greater than the performance of most domestic models. The result is that the spectrum of work performed noticeably wider, it is possible to twist the screws thick (more than 3/16 “) drill brick, perform the operation that requires considerable effort. Secondly, the time required for full charging significantly less. Some models are charged 100 minutes, some with fast charging just half an hour. Domestic same cordless drills usually 3-5 hours, which is not permissible for the intensive work and the workplace. Professional cordless drills are always at least two batteries included, sometimes three. The price of a professional is much higher than in the consumer class, with the same characteristics of the above, it is two or more times.
Battery capacity cordless drill plays an important role, often an indicator of 1.3 ampere hours, at least 1.5 or 2. The figure is, the more you will be able to work without recharging the battery.
How to work? The thinner and shorter screw, the less you need to put the torque, the sooner will trigger ratchet. When the screw is fully spun into the workpiece, it works, and the cordless drill chuck scrolls in place, thus not overwritten cap screw and does not deteriorate a bit. The torque must be chosen for each individual screw, depending on the diameter and length. For thick roofing – put a little more.
Some cordless drills have two speeds, first from 0-400 revolutions regulated rpm, the second 400-1200. For tightening screws usually suffice first speed to place the second hole. On other models, the speed is regulated only by the Start button, the stronger the presses, the greater the speed.
There is also a model without speed control (rarely), so turn the screws very uncomfortable, pressing the start button once the maximum speed is activated. Especially uncomfortable when tightening the screws little short.
Sometimes cordless drills equipped carrying case (professional always), a set of bits, a flashlight. Little things, but pleasant, it is worth paying attention to.
There are commercially available and rechargeable cordless drill, not to be confused with a cordless drill. They are intended for screwed connections (computer assembly for example) but not for the screws. Some unscrupulous sellers try to sell as a cordless drill, especially teleshopping. Torque them 2.5-4 N / m, which is not enough to tighten the screws. If twirl, only a very thin and very short.
Manufacturers. Among the domestic class behave «Skil» well, «Black and Decker», «Bosch» green.
From professional well established «Bosch» blue, «Makita», «Hitachi», «AEG», «Dewalt».
In our time, will not be difficult to purchase any cordless drill to your taste, good tool shops abound, if there is no time and desire, it can be purchased at online stores. Good luck to all choices.