How to Buy A Screwdriver?

The family will often use a small screwdriver, we should understand how to buy,  and buy a high durability of the screwdriver is also a knowledge.
We need to pay attention to the effective working length of the screwdriver, a screwdriver is a tool that uses the physical characteristics of the axle, when the wheel is larger, the smaller the required torque is. So most of the screwdriver handle will be much thicker than the screwdriver head. If you choose the product pole length is too small, screwdriver when the screwdriver will be very laborious.
Second, pay attention to screwdriver material, screwdriver steel is the main raw material of the goods, we can query the relevant hardness data, then comparing our own needs, to determine the screwdriver steel hardness and model.
Finally choose a combination of screwdriver set. Ordinary screwdriver can only meet some of the needs of life, the shape of the head is relatively simple, if life encountered more special screws, it can not play a role. Combined screwdriver can adapt to a variety of unexpected situations in life, and even to meet some special needs.