In the house to do without screw driver quite difficult. This tool is necessary both at major repair, and in different everyday situations – whether it be assembly of cabinet or replacement of the lock. To choose the ideal screw driver from the modern wide range not easy therefore it is necessary to be guided not so much by its advertizing, how many by technical characteristics.
Key parameters of the screw driver
The most important parameters of the tool – torsion torque and rotating speed. The screw driver which maximum torsion torque makes 10-15 Nanometers perfectly will be suitable for household use. It allows to twist easily even the hardest self-tapping screws. Tools with high torsion torque are generalpurpose as with their help it is possible to drill solid materials also.
At professional expensive screw drivers the maximum torsion torque can reach up to 130 Nanometers.
The choice of rotating speed depends on problems which will be solved by the tool. To twist screws, there will be enough parameter in 400-500 RPM. Drilling requires rotating speed not less than 1200-1300 RPM. Big frequency is necessary only in exceptional cases. Also when choosing the screw driver it is necessary to pay attention to the reducer providing rotation of its working shaft with the set angular speed. For twisting quite will be enough 50 RPM, for drilling - from 1200 to 1500 RPM. Cordless screwdrivers are most often equipped with planetary reducer with plastic satellite gear wheels.
Professional or household
If you doubt what screw driver to choose – household or professional, pay attention to power and time of continuous operation before recharge. Both indicators at the household screw driver much less, however in life such tool will cope with all tasks. The household accumulator is usually equipped with the nickel cadmium accumulator which is enough for 1000 chargings.
The cost of household screw drivers also significantly differs from expensive professional tool which is reasonable for buying only for heavy loads.
It is desirable to choose professional cordless screwdrivers with Li-ion batteries which do not suffer from "memory effect" and do not contain noxious to health cadmium. Their only minus is bad resistance to subzero temperature. Also you can buy the household or professional screw driver working from network. Such tools weigh more and are limited to cord length. It is reasonable to choose them at large volumes of the work connected with processing of solid materials. Besides, upon purchase of the screw driver give preference not to the handle of pistol type, but the handle located on its centroid. And it is even better - read responses on the websites of consumers where direct users will tell you about various brands of the tool - makita, bosch, hitachi and others.