Screwdrivers, no matter how simple they are at first glance, differ in such a variety that you are simply amazed! The fruits of scientific and technological progress are available today to the buyer in abundance, the market economy does its job: whatever the manufacturer is, the original development. But do they know about them, sometimes choosing according to the principle “a screwdriver – it is a screwdriver in Africa,” and why overpay for it? And then calluses on the palms, a twisted tip, rolled screws, etc. – “epiphany” bought for their own money. So what to look for when choosing this hand tool?
So the handle
Since the grip is in constant contact with the user’s palm, its advantages and disadvantages are determined by two factors – the materials used and the geometry. The latter determines how the force will be transmitted to the screw, what moment and axial force will make it “take its place”.
The ergonomic shape provides for the transmission of high torque a zone of large radius at the end of the handle with a wide round “nape” without sharp edges, and closer to the shaft – a narrow section (“waist”). It allows you to quickly twist the tool with your fingers.
In addition, in most “round” models, a pair of edges are specially grinded so that the screwdriver does not roll off inclined planes. “Holes” towards the end of the handle are holes for hanging (it is more convenient to store the tool this way).
About material. For specimens intended to transmit high forces, close contact of the handle with the palm and the absence of slippage (this can lead to rubbing of corns) are important. To solve these problems, the plastic bodies of the ergonomic handles are equipped with rubber inserts. The reverse side of the coin is the chemical resistance of the material, that is, the ability to withstand contact with oil, gasoline, solvents or acetone without consequences. Most multi-component handles (with rubber inserts) are designed for use in dry environments, although short-term exposure to chemicals is not hazardous. But if you know for sure that the working conditions will be harsh (from a chemical point of view), you will have to put up with an all-plastic handle. Rare, but there are specialized products with lacquered wooden handles, their range of tasks is associated mainly with woodwork.
Since plastic is a soft material, not every screwdriver can withstand hammer blows. Nevertheless, sometimes you cannot do without it (the most common example is a rusted screw, less often using a tool as a chisel). The readiness for axial impacts is indicated by a metal insert on the “crown” of the handle. In such samples, the rod goes through, ending with a knob, and blows on it do not affect the handle in any way.
Now – about the screwdriver shaft
It all depends on the metal. Competent manufacturers do not skimp and use high-alloy steel (most often chrome vanadium), which ensures durability of the tool. With poor quality of the material, the product sometimes looks attractive, but it does not withstand even a month of active work, grinding and bending. This, by the way, can also happen with good steel with poor hardening, so hardness is one of the main indicators of tool quality. It is no coincidence that it is even stipulated “legally”. According to GOST 10754-93, the hardness of the working part should be in the range of HRC 47-52. A shortage of this indicator threatens with excessive plasticity, grinding or bending, overkill – fragility and fragility.
The main enemy of metal is corrosion. To protect against it, the rods are usually chrome plated..
The profile of the bar is most often round in cross section, although there are also models with a hexagon. The synthesis of such solutions is a round rod, reinforced with a hexagon near the handle. With its help, a wrench can easily transfer a large force to the screw.
As for the length of the rods, it varies widely. But all these variations have a single goal – to find the most convenient model. So, there are “shorty” screwdrivers that fit in the palm of your hand, and “trucker” screwdrivers, the shaft of which is several times longer than the handle. With all the difference, both of them facilitate the approach to hard-to-reach places..
There are also “originals”, for example, double-bend screwdrivers. They have a rod with a sting bent at 90 degrees from each end of the handle (as a rule, they are different). There are also screwdrivers with a flexible shaft, that is, with an insert between the handle and the tip, allowing you to work under bending.
And the last is the sting
There are not so many widely used types of screws, and for each there is a sting of a certain geometry.
A good tip should not slip on contact with the head, which is why many manufacturers roughen the tip or even make a notch on it. In many expensive models, a special compound is sprayed onto the tip to improve engagement..
Some manufacturers use a special hardening technology in which the hardness of the tip exceeds the hardness of the rod itself. However, the black color of the tip should not be explained by a special heat treatment: this is the result of oxidation (bluing). It is designed, in addition to anti-corrosion protection, to improve the grip: the surface is rough, not slippery.
Has taken root among modern screwdrivers and color indication, when the color of some elements of the handle indicates what kind of sting it has. This makes it easier to select the desired sample from the toolbox.
Convenient feature – magnetized tip. You can even find a device for magnetizing and demagnetizing screwdrivers on the market..
Some models have a retainer to hold the screw on the tip.
Many who are tired of screwdrivers that rip off heads, bend and break, really want to have a set of useful tools.
Nice boxes stuffed with imaginable and inconceivable “attachments” immediately attract attention – beautifully, varied and, as a rule, inexpensive. But, following our advice, now you can easily see any disadvantages and advantages behind the external tinsel.