Tool for working with an internal profile. This is the official name of the familiar screwdriver for all of us.
According to one of the versions, the screwdriver leads its history from the depths of the 16th century, when Leonardo Da Vinci himself had a hand in its creation.
It would seem, what could be easier than choosing a screwdriver? I came to the store, chose and bought. However, the seemingly elementary design of the instrument conceals many secrets.
Let's figure out what and how it works in a screwdriver.
The main parts of the screwdriver are the shaft and the handle. In turn, the rod has a working area - a tip with a slot, and the handle consists of a base material, an additional layer or linings and options, such as a hole and a hammer.
All these parts and materials together affect the manufacturing quality of the screwdriver, its performance and durability.
Screwdriver shaft
The key working part of the screwdriver is its steel shaft.
Steel type
The steel grade directly affects the characteristics of the bar. How the rod behaves as the torque applied to the screwdriver increases. To what extent it is capable of elastic deformation, and at what point does irreversible destruction occur.
Screwdrivers, which can be found in the retail sale of hardware stores and hypermarkets, are mainly supplied with rods made of such types of steel as:
- carbon steel
- chrome vanadium steel Cr-V
- chrome-molybdenum steel Cr-Mo
- steel S2
- steel SVCM
The most affordable carbon steel is the lot of simple and budget screwdrivers. If there is no marking on the rod, then this is exactly the steel in front of you. Its only plus is its low price.
The next option is chrome vanadium steel. This is the most common material for screwdriver pins. She has sufficient plasticity. At high loads, Cr-V deforms irreversibly.
It is extremely rare for some manufacturers to use chromium-molybdenum steel. Although Cr-Mo is more suitable for pliers, pliers, pliers. It holds shock loads well, but withstands the torsional load weakly.
One of the best steel options for a screwdriver is S2 alloy steel. It contains molybdenum and silicon. S2 resists loading well, but collapses when the limit is reached. Due to its low plasticity, it has a low threshold for reversible deformation. Sometimes S3 steel can be found as an improved version of S2.
State-of-the-art development of steel makers SVCM steel. Its composition is specially selected for the needs of screwdriver production. SVCM combines the advantages of Cr-V and S2 steels - hardness, toughness, ductility and high reverse deformation threshold.
Test schedule for screwdriver rods made of Cr-V, S2 and SVCM steels Bar section
Most of the screwdriver rods are round. This is due to the peculiarity of the production cycle. The rods are made from wire, which metallurgical plants draw precisely round.
Round shank Jonnesway screwdriver
Less common bar sections are square and hex.
 Square Shank Screwdriver |
 LUX Screwdriver with Hex Shank |
Such sections are typical for power screwdrivers. The profile of the rod with edges allows you to apply additional force to the screwdriver with a wrench, multiplying the torque.
Rod coating
To protect the steel from premature corrosion, a protective coating is applied to the surface of the rods.
Most often it is a matt chrome-nickel coating, applied by galvanizing.
Matte finish on shock rods
Some manufacturers chrome the rods to a mirror finish. In addition to the catchy elegance, such a coating greatly facilitates the care of the screwdriver. To wipe dirt or remnants of fuels and lubricants from the chrome rod, just walk with a dry cloth.
Chrome plated screwdriver shaft
Screwdriver tip
The main working part of a screwdriver is its tip. It is also sometimes called “sting”. To make the tool last a long time and not be a hassle, when choosing a screwdriver, take a closer look at the tip.
Processing quality
First of all, you should visually examine the quality of metal processing on the tip. Edges and surfaces must be carefully milled and sanded. There should be no burrs or scuffs.
LUX Power Screwdriver Tips The protective layer of black paint must be intact. If the paint is worn or not at all, then most likely the screwdriver has already been worked, and it is not new.
If you know in advance which screwdriver with which slot you are going to buy, take a sample of fasteners with you to the store. A well-machined tip should fit tightly and without play into the inner profile of the screws and screws.
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The tightness of the screwdriver tip to the screw slots
Hardening
Of course, you won't be able to check the degree of hardening of the tip by eye. You will have to rely on the honesty of the sellers and the frankness of the manufacturers. But it’s worth asking to what hardness the sting is hardened.
The best examples of screwdrivers boast tips hardened to 52-58 HRC.
Magnetization
But magnetization, unlike hardening, is easy to check on site. It is enough to attach a screw, nut or screw to the tip.
A good-quality screwdriver has a tip that confidently holds a screw, even a large one.
With a magnetized tip, it will be much easier to work with fasteners in the future. The magnetised screw will not come off the screwdriver if you screw it in a hard-to-reach place.
Screwdriver slot
The most common types of screwdrivers are offered with the following slots:
- straight slot SL
- phillips or Pozidriv cross recess
- hexagonal torx slot
The slots are offered in a wide range of sizes, as they say, for any tricky screw.
Of course, the variety of splines is much wider. But other types of slots in the form factor of a classic screwdriver are critically less common.
The choice of slot depends on what tasks you plan to solve with a screwdriver.
Screwdriver handle
The handle of the screwdriver is just as important as the shaft. When choosing a tool, you should study the profile of the handle, the base material, whether there are pads or additional coating. And also the ability of the handle to withstand the corrosive effects of petrochemicals.
Cross section of the handle
Handle shapes are now limited only by the imagination of designers and industrial designers. And there is no need to advise which one to choose, since there are too many options.
But there is one parameter that you definitely need to study before buying. This is a transverse profile. It directly affects not so much the comfort of work as the amount of torque that can be transmitted through a screwdriver to the fasteners.
The three main handle profiles are round, triangular and hexagonal.
Round profile
Round profile screwdriver Matrix In cross section, the handle is a circle. This form is convenient to manufacture - injection molds are easy to manufacture. However, in terms of torque, this is the weakest handle option. The palms have nothing to securely hold on to. And slippage is more than likely.
Triangular profile
Triangular screwdriver profile The triangle at the base of the handle is the best option in terms of torque. The triangular profile follows the anatomical shape of the compressed palm and allows you to transfer maximum force to the fastener.
Hexagonal profile
Hexagonal screwdriver profile The hexagonal profile of the handle is the second in quality for transmitting torque to the fasteners. It is better than the round one, but inferior to the triangular one due to less conformity to the anatomy of the hand.
Any hexagonal handle got special in America, where this form of screwdrivers is considered classic.
Base material
Modern screwdriver handles are made from various types of plastic and thermoplastic rubber. The days of wooden handles or all-steel handles are a thing of the past.
The most widespread are solid-cast one-component and two-component handles. Impact-resistant plastic grades are used as a basis for both.
Often, for a decorative effect, two-component handles are made of transparent plastic.
Swiss Tools PB195 one-piece screwdriver handle In two-component handles, opaque plastics are often used as a base.
The transparency / opacity of the grip base plastic does not affect performance.
Overlays or additional cover
If there are no other materials besides the base in one-component handles, then in two-component handles there is a second surface material or linings.
This material simultaneously increases friction between the hand and the screwdriver and acts as a shock absorber.
The handle of the screwdriver is covered with santoprene on the top
The anti-friction coating can either cover almost the entire area of \u200b\u200bthe screwdriver, or be separate pads in the most friction-loaded planes.
In Ombra Basic, rubber grips resemble fenders The best option would be thermoplastic overlays. With a similar coefficient of friction, they are better at absorbing shock vibrations than conventional rubber. This means that the hand will be less tired with them.
Petrochemical corrosion protection
This parameter is important for those who are going to actively use a screwdriver in the garage. It is full of various petrochemicals - gasoline, car oils, brake fluid. All of this is quite caustic and can be detrimental to the grip.
The sturdy handle is made of materials that can withstand the effects of petroleum products. Plastic, thermoplastic rubber pads - all this should live even if you drop a screwdriver into a bucket of gasoline.
It will be difficult to check the resistance of the materials at the store counter. Therefore, at a minimum, you need to ask the seller a question. Experienced traders know which of the screwdrivers are neutral to fuels and lubricants, and will always tell you what to choose.
Additional options
In addition to the central structural elements - the rod, the tip and the handle - some manufacturers' screwdrivers are equipped with additional chips that make their daily use a little more convenient or add new functions to the tool.
Hole in the handle. Refers to options that increase the comfort of use. A screwdriver with it can be hung on a tool stand or simply on a nail in the wall.
Hole in the handle of the Dexell screwdriver Slot for power rotation. Adds a new degree of freedom to the screwdriver. You can attach a wrench to the slot and multiply the force applied to the fastener. As a rule, power screwdrivers have a similar slot.
LUX screwdriver slot 
Dexter screwdriver slot Striker under the hammer. An additional steel platform on the back of the handle allows the use of a hammer. Of course, it is not worth driving the screws with the help of the “screwdriver-hammer” system, but to drive the tip into the inner profile of the rusted screw more tightly is what you need.
Firing pin on a screwdriver
In some cases, when there is no particular trepidation for the tool, a screwdriver with a hammer head can be used as a punch, center punch or even a stone chisel.
Portrait of the perfect screwdriver
As a summary, let's try to make a composite of an ideal screwdriver that will last for many years.
We would like to thank Pride, Instrument World, Leroy Merlin and Obi hypermarkets for their participation in the preparation of the material.
- Those who often have to deal with metal usually use a blowtorch. And it is far from safe. - says A. Belinsky from Novocherkassk. - Is it possible to do without a blowtorch to avoid explosions and fires? Can! You just need to acquire a blacksmith forge.I have been working with a small forge with an electric fan for several years now. Despite its small size (the forge fits in the hand), I can heat a soldering iron, perform hard soldering, forge cutters, melt aluminum and bronze in a small crucible, and carry out small forgings.
The fuel is charcoal (the best fuel, does not smoke and flares up quickly), smoked blacksmith's coal (smokes a lot, but gives a very hot flame, suitable for all work), wood chunks (preferably hard wood.
To make a forge, you will need a paint can of ∅150 mm, a fan with an electric motor from a children's toy "Vacuum Cleaner", a piece of an iron tube ∅15 mm and 100 mm long. Carefully cut the bottom of the beam, straighten it and insert it into the can halfway up. Make 3 triangular notches in the walls, which turn inward.
Lay the bottom on the folds, punch a hole in the side wall of the can corresponding to the outer diameter of the tube. Insert the latter into the hole and coat the inside with clay to form a deepened hearth for burning coal.
Attach the fan with a blower nozzle to the horn tube using insulating tape and turn on the battery. That's all. It took the author about an hour to make the forge.
A large horn is easy to make from a heating fan from a car and a large (conical) bucket. Almost all blacksmithing works can be performed in such a forge.
Clamp screwdriver
When assembling or dismantling a structure, says L. Dunaevsky, a senior technician from Chisinau, when access to screws or threaded holes is impeded by other parts, a screwdriver with a grip acting on the principle of a collet pencil is very useful.The tool consists of a handle and a rod on which a collet with petals slides. The backward travel of the collet tube is limited by the stop of the rod, and forward by the size of the screw to be screwed in. To grip it, we pull the screwdriver body back to the handle: the collet petals diverge and the working part of the screwdriver is exposed. Insert the tool tip into the screw slot and release the case. Under the action of the spring, it will squeeze the collet petals with its edge, and they will compress and hold the screw until the head begins to approach the plane to be fastened. On the last turns, the head pushes the petals holding it apart until it slides off completely - the screw is in place, the grip is released.
A screwdriver is a tool that, perhaps, most characterizes a "do-it-yourselfer". Any self-respecting "jack of all trades" comes up with a "personal" screwdriver, unlike any of the previously seen.
There are so many accessories for screwdrivers! And simple ones, like, for example, a hex nut welded to the base of the rod for unscrewing the most "stubborn" screws with a wrench (Fig. 1). And complex, which can only be done by a qualified specialist. Try and you will benefit from the experience of the craftsmen
A permanent magnet built into the screwdriver handle (Fig. 2) can make work much easier when it becomes necessary to tighten the screw in a hard-to-reach place. By moving the button, the magnetization of the tool tip is switched on, and the screw is thereby “glued” to it.
The handle is machined from wood or PCB; a tension spring is wound from a steel wire of 0 0.5 mm. The contact surfaces of the magnet and the screwdriver shank must be carefully matched to each other. The same effect can be achieved if magnetization is performed using a solenoid coil, the core of which is a rod (Fig. 3). The electromagnet is turned on by a button that moves the battery.
You can also hold the screw in a purely mechanical way - using a Ø 3 mm round rod located inside the screwdriver shaft (Fig. 4).
The grip of the screw head occurs when the latter is turned by a small angle using a lever located on the handle. The simplest voltage indicator on a neon lamp, built into the handle of the tool (Fig. 5), will warn you of the presence of voltage when replacing, for example, a switch. To do this, you need to touch the contact with the sting, and touch the protruding rod with your hand. The value of the additional resistor is 22 - 100 kOhm.
The screwdriver shown in Figure 6 will help you if the screws are in a shaded area. Its handle houses a battery, a flashlight lamp and a switching device. The light passes through a precision-polished plexiglass optical fiber adapter.
To work with small diameter screws, use the design shown in Figure 7. By rotating the movable rod, you can tighten or unscrew the screw while the handle is stationary, without risking "losing" the slot. The tip is locked by pressing the handle until it stops.
"Quick wrench" - this is how you can call the next tool (Fig. 8). Even a very long screw can be tightened with it in a matter of seconds. This advantage is especially pronounced if there are many screws. The screws "reach out" when the rod is fixed, for which the stopper slider must be moved to the left.
And finally, on the eve of April 1, we offer the last tool in our selection (Fig. 9). Outwardly similar to a screwdriver, it is not at all. The figure shows a portable laser soldering iron, which is convenient for soldering elements of radio circuits on printed circuit boards.
The Scientific and Technological Revolution (STR), which caused the rapid growth of laser technology, made it possible to create a portable light pulse generator available to an average radio amateur.
The main part of this uncomplicated laser soldering iron is a highly polished organic glass rod.
With a rod length of 176.4 mm (from end to end), the temperature 20 mm from the radiating end is about 200 ° C.
"Pumping" is carried out using a conventional incandescent lamp for a voltage of 3.5-4.5 V. An important role in the formation of the laser beam is played by a reflector-reflector made of aluminum foil.
The pumping lamp is supplied with rectangular voltage pulses with an amplitude of 117.4 V, a repetition rate of 31.4 Hz and a duty cycle of 0.001.
Readers who have expressed a desire to make a portable laser soldering iron, the editors congratulate on April 1 and ... nevertheless recommends to make it for highlighting the shaded areas of the radio assembly when desoldering parts.