Many people still believe that a screwdriver blade can only be of two types:
- splined - Ps
Popularly referred to as “minus” - flat.
The very concept of slot (schlitz) is translated from German as a groove or slot.
- cruciform
Moreover, as some believe, they differ from each other only in size (width and thickness of the tip) or diameter.
In fact, the shape of the cross-shaped profile also plays a significant role.
Moreover, the “cross” itself appeared much later than the slot. Due to the massive introduction of screwdrivers, using a straight slot with these devices has become not entirely convenient.
Therefore, we gradually switched to a cruciform shape. It centers better and is much easier to work with.
Screwdriver profile Ph
The cross-head slot we are used to was invented back in the 30s. A few years later, the patent for this invention was bought by the enterprising Henry Phillips.
G. Phillips patent for Ph profile
This profile was named in his honor - Ph = Phillips. Just don't confuse the Philips company from the Netherlands (with one L) with the Phillips Screw Company founded in the USA.
We know the first one well from televisions, cassettes, high-quality lighting devices, etc. But the second one gave us variety in threaded fasteners.
At first glance, Ph is a simple cross, narrowed to the base and nothing more. It would seem that there is nothing to invent and patent here?
But this is not true at all. The Ph profile is made strictly at a certain angle of 55 degrees and with an inclination of the side surface of each face.
Thanks to this, if you start tightening screws or screws with extreme force, risking overtightening them, the bit or sting will simply pop out of the head of the screw or screw without damaging the fastener itself.
As you know, this was not done by accident. In this way, a certain tightening torque was achieved when using the tool on flow assemblies of the automotive industry and aircraft manufacturing in the USA.
Subsequently, with the invention of torque ratchets, screwdrivers and screwdrivers, as well as increased requirements for precise tightening torque, this began to work to the detriment.
In practical terms, this means that you don't have to mutilate the Ph bit if it starts popping out of the fastener. It turns out that the limit of the screw's tightening ability has been reached and there is no need to turn it any further.
Recommendations for choosing bits for work
The market for attachments designed to equip a screwdriver is filled with products of varying quality and from different companies. For this reason, the question is relevant: which manufacturers’ products are best purchased as a set, and which ones separately? The correct choice in this case determines not only the time of use of the purchased bits, but also affects the service life of the power tool used, and also affects the quality of the work performed.
Tips for purchasing piece goods
For individual purchase, experts recommend Whirl Power (WP) brand products. It can be easily distinguished from analogues by the presence of a branded green sticker. The products of this company have earned great popularity and authority due to their good magnetic properties, as well as significant hardness, which increases service life due to slow wear. The attachments can be easily inserted into the chuck without falling out when the power tool is tilted down. Magnetic bits hold metal fasteners well - this allows you to conveniently perform work in hard-to-reach places.
For practical use, the following bit sizes from Whirl Power are popular:
- 25 mm;
- 50 mm;
- 75 mm;
- 90 mm.
Long nozzles measuring 150 mm are also widely used.
To work with most types of fasteners, standard WP2 models are used. If you need to perform operations with decorative modifications of self-tapping screws, then use tips for a WP1 screwdriver. The working parts are equipped with notches that increase their resistance to wear.
Almost as popular as Whirl Power among buyers are products from Bosch, which traditionally supplies the market with high-quality power tools. The quality of screwdriver attachments from this brand is also emphasized by their high price. At the same time, titanium-coated products, marked with a yellow color, are especially popular. The main materials for their manufacture are chrome vanadium, tungsten molybdenum or chrome molybdenum alloys. In addition to titanium, tungsten carbide, diamond or nickel are also used as a protective coating for the working parts.
Cheaper competitors to Bosch are hardware from DeWALT. Their distinctive feature is a high degree of impact resistance. They can be used regularly for a long time. For everyday use, hardware from Magna is also suitable. If handled carefully, they can last a long time.
If you need to buy equipment for a certain type of fastener, it is recommended to take a sample with you. This will allow you to choose the best tip option by trying it on the cap before purchasing.
Popular attachment kits
You can select bits for a screwdriver in one set. The stores offer many ready-made selections of hardware, packaged in boxes that are convenient for storage and use. In such cases, each element is placed in a separate place, while its size is indicated next to it.
Professional sets of attachments from Hitachi and Kraftool stand out among competitors for their excellent quality. They contain hardware of all standard sizes used in various fields of practice.
If you buy a set of high-quality hardware, then such a purchase will cost less than purchasing a similar product individually. Purchasing a kit, allowing you to save money, is very convenient when carrying out professional activities.
Despite the wide variety of shapes of working tips for screwdrivers and differences in the material from which they are made, in any case you should choose high-quality equipment. Purchasing products from well-known brands that have proven themselves over many years is the right decision for professional activities and large regular volumes of work performed. Such products will last a very long time, contributing to the efficient performance of work tasks. Low-quality, cheap kits can be purchased for household use. But it should be borne in mind that they wear out quickly, causing a lot of inconvenience during the work process.
Profile Pz - main differences
In 1966, the same Phillips company modernized its earlier invention and introduced the Pozidrive slot - Pz (Pozidriv) to the world.
Its distinctive feature is:
1Additional edge located in the quarters of the slot.
The bit turns out to be 8-spline. Four main faces, four additional.
At the same time, the heads of self-tapping screws and screws received similar notches. All this allowed for even better centering of the tip.
2The edges of the working surface in Pz, unlike Ph, are made parallel to each other, and not at a narrowing angle.
With Ph, this taper is made specifically so that at the end of the twisting operation, the bit pops out of the head. The so-called self-pushing effect.
When Pz was invented, they abandoned this, shifting the responsibility of limiting the force to the screwdriver or torque tool itself.
3 Ph bits and screwdrivers have a slightly different sharpening angle - 50 degrees.
Thanks to all these modifications, the spline began to fit much deeper into the mounting hole of the fastener. Which led to increased tightening of self-tapping screws.
In simple words, we can say that Pz is a reinforced cross-shaped spline.
Classification of bits by material and coating
Their strength characteristics and wear resistance depend on the properties of the material from which the hardware is made, as well as on the coating.
The following alloys are considered the best for the manufacture of screwdriver attachments: chromium-vanadium (indicated by the symbols Cr-V);
- chromium-molybdenum (Cr-Mb);
- tungsten-molybdenum.
Hardware is also made from other metals, for example, from high-speed steel (from R7 to R12). But such cheaper alloys are inferior in their performance indicators (strength, wear resistance) to the considered options.
The screwdriver attachment for self-tapping screws, bolts and other types of fasteners can be coated with the following materials:
- nickel;
- titanium;
- tungsten carbide;
- diamond coating.
The applied coating increases the resistance of working tips to corrosive processes, increases their wear resistance, as well as strength characteristics. Titanium coating emphasizes the quality of the product. It has a yellow tint.
Features, sizes and where to use
Pz is used mainly in furniture assembly and construction.
It is not as common in machine manufacturing or metalworking. This is explained by the fact that due to the greater depth, the posidrive fasteners must have slightly larger heads. Otherwise, their strength decreases and they break off.
Well, a larger size always means more weight, which is often unacceptable in some critical industries.
Moreover, both splines have 5 main dimensions, rigidly tied to the diameter of the fastener.
The most common numbers are 1, 2 and 3. Both Ph and Pz.
The most popular of them is the Pz2. It’s not for nothing that in sets of bits, this size is usually included in 2 pieces. It is used most often and, as a result, wears out most often.
Walking into a hardware store, a knowledgeable buyer immediately tells the sales consultants: “I’d like a set of two Pozidrive bits, please.”
Amateurs and non-professionals usually call them “double plus”! Be literate in such seemingly small but important issues.
However, the correct name is not the key to success. Having the same names, bits from different manufacturers may differ.
The highest quality brands are Wiha, Wera, Milwaukee.
If with the Ph profile everything is still more or less smooth and not everyone can mess up, then with the Pz profile a real disaster happens. Chinese bit manufacturers simply do not follow the sizes and standards.
So it turns out that some bits are thicker, others thinner. The same goes for fasteners. Unfinished notches in the head of a screw or self-tapping screw are completely commonplace. As a rule, this is observed in the smallest sizes up to 20mm for Pz1, Pz2 and Ph1 bits.
In this type of fastener, the tip of the bit already rests against the notch, but there is no edge of the bit yet. As a result, the screw begins to dangle like a metronome. Therefore, when purchasing in bulk from a store, it is advisable to immediately try on the bit with the fastener head.
What to look for when choosing
Many people treat bits as consumables, considering it normal that they quickly fail and begin to turn. However, the service life of nozzles can be significantly extended not only by selecting them correctly for self-tapping screws, but also if you pay attention to the material used to make the nozzle.
Don't skimp on the more expensive titanium-coated splines, as they end up being cheaper than several standard bits made from softer materials. Classic products are made of steel alloys, but they may differ in terms of rigidity.
In addition to titanium-coated nozzles, bits of chromium and molybdenum or tungsten have good characteristics. It is also worth giving preference to those attachments that have undergone heat treatment. In addition to titanium, nickel can be used to process nozzles, with which the products are coated in a special vacuum environment, which completely prevents any particles from getting under the coating. There are also bits reinforced with diamond inserts.
Electrician's screwdriver for vending machines
As for electricians, it is no secret for competent specialists who have been working in this field for a long time that bus bars, cross modules, automatic machines, relays and other equipment have special screw terminals Pz +/- or Ph +/-
Moreover, it was for electricians that manufacturers began to produce special screwdrivers with a Pz/fl or Pz/s profile for automatic machines.
And also Ph/fl or Ph/s - for busbars, starters, relays, etc.
The designation for this spline (Fl or S) is different because until recently, it was not standardized. So they called him whatever it was more convenient for him. Although the essence and form were the same.
Currently it is standardized only in France and the USA as Pz/sl and Ph/sl.
For sockets and light switches, in 90% of cases the first number is needed, and for modular machines, number 2 is required.
The screw clamps of such devices have not only the usual cross with notches characteristic of Pz, but also a wide slot for a flat-head screwdriver.
On the one hand, they are made this way so that even those who do not have the appropriate tool can tighten everything with a regular flat-head screwdriver. Or, when the working slot was already “killed,” you could at least unscrew the screw one last time, then pull out the wire and replace the machine.
But on the other hand, if you twist them with a simple Phillips Pz or a regular spline, then the bit will still slip at the last moment, without tightening the contact with the required force.
And the universal combination screwdriver Pz/Fl or Pz/Sl is just right! However, be careful when choosing manufacturers. There are a lot of negative reviews of such profiles on the Internet.
In them, the corner of the flat slot breaks off first. Especially in the first issue.
Using screwdrivers and bits with incorrectly selected fasteners leads to wear of both the screwdriver itself and the head of the screw or self-tapping screw.
In this case, the worst thing happens when they try to tighten the Ph profile with a Pz screwdriver. The contact of the edges in this case is minimal.
From the first revolutions, as soon as a significant load begins, you are guaranteed to break not only the fasteners, but also damage the edges of the bat itself.
Types of bits
The screwdriver accessories consist of the following accessories:
- magnetic or regular bits and holders for them (extensions);
- drills
The bit is a rod with six edges, on one side of which there is a working profile, and the other end is intended for fixation in a power tool chuck or in a holder. This special nozzle must be sized to match the type of fastener (self-tapping screw, screw, screw, bolt, etc.).
Drills for screwdrivers represent a separate category of equipment. They are taken from ordinary (unstressed) drills. In this case, the maximum diameter of the drills is limited by the largest cross-section of the tail section, which the tool chuck is capable of clamping.
Existing types of bits differ in the shape of their working part. Based on this feature, the following groups of this equipment are distinguished:
- main (standard), which includes straight, cross-shaped, hexagonal tips, as well as in the shape of an asterisk and for bolts;
- special, for example, bits equipped with spring clamps, limit stops (designed for screwing drywall sheets), triangular;
- combined, in which the nozzles are equipped with two working parts of different shapes or sizes.
Bit extenders are divided into two types:
- magnetic, holding the inserted nozzle due to the force of a magnetic field;
- spring ones, in which the tail part is fixed rigidly.
Standard equipment
Standard attachments are included in any set; they are used most often in work. The very first of the variety of equipment to appear were straight (slotted) bits. This classic option is designed to work with screws or screws that have a straight cut. Spline equipment is marked with the letter S (from the word slot), next to which a number is placed. The number indicates the slot width, which ranges from 3-9 mm. The thickness of the tip is not specified, but its standard value is in the range from 0.5 to 1.6 mm. The marking located on the shank also contains an indication of the material from which the equipment is made.
There are spline bits with a gold titanium nitride coating. Then the marking contains the TIN designation. In this case, the width of tips with titanium coating can be from 4.5 to 6.% mm, and the thickness - 0.6-1.2 mm.
There are elongated spline-type nozzles. They are 5-10 cm long.
Cross-shaped (cross) bits are divided into two groups:
Ph (from Philips) - a universal type with a length of 2.5 to 15 cm (there are also 30 cm flexible holders), with a working part of four diagonal ribs;
PZ (Pozidrive) is a tool of different lengths, equipped, in addition to 4 main ribs, with four additional ones.
Philips equipment has four standard sizes: from Ph-0 to Ph-3. The number corresponds to the outer diameter of the fastener.
Pozidrive attachments come in the following sizes:
- PZ0 are used to work with screws up to 2.5 mm in diameter;
- PZ1 - they are used to tighten fasteners from 2.5 to 3.5 mm;
- PZ2 are designed for 3.5-4 mm screws;
- PZ3 and PZ4 allow you to work with large screws and anchor bolts.
Cross-shaped equipment is the most common compared to other varieties. It may also have a titanium coating.
The hexagonal bits are marked with the letter H (from the phrase Hex socket). Such attachments can be:
classic type, size 1.5-10 mm;
hexagonal in shape, but with an internal hole (their dimensions range from 1.5-6 mm);
elongated, with working part sizes from 3 to 8 mm and a length of 5-10 cm.
Star bits are marked with the letter T followed by a number. They are used in the assembly/disassembly of household appliances, as well as cars. They come in the following varieties:
Torx (classic), sizes T8-T40;
Torx Plus (their beams are less sharp), sizes from T10 to T40;
with titanium coating (TIN), sizes T10-T40;
with internal hole (standard size T10-T40);
elongated: sizes from T10 to T40, length 5-10 cm.
Nozzles designed for tightening or unscrewing fasteners with a hexagonal head (bolts, nuts) have a size of 6-13 mm. The most common of these are eight-millimeter bits.
Special attachments
Special equipment includes the following types of bits:
three-blade (Tri wing), sizes TW0-TW5;
four-blade (Torq-set, designated Gr), size 4-10 mm;
classic and elongated tetrahedral (Robertson square, with a square slot), designated by the letter R;
elongated and classic “fork” shaped (designated Gr).
There are also tips with other special shapes, but they are used extremely rarely.
Handle
Screwdriver handles are made from various materials, such as plastic, wood, and may have rubber inserts.
The dimensions of the handle must be selected based on the working conditions. If you have to work in cramped conditions, a short handle is better. Its diameter is almost always proportional to the size of the tip and the diameter of the rod. That is, the more powerful the fastener a tool is designed for, the greater the torque required and the thicker the handle should be. For screwdrivers for small fasteners, the handles are deliberately made thinner so that there is no risk of cutting off the slot or destroying the part into which the fastener is screwed.
The handles of modern screwdrivers can come in a variety of shapes; often manufacturers are guided not only by ergonomics, but also try to somehow distinguish their product from others due to the shape of the handle, sometimes sacrificing convenience. Therefore, when choosing a screwdriver, we recommend that you hold it in your hands.
The handle of a screwdriver can be not only cylindrical; there are T-shaped handles or pistol-type handles. They provide more torque, but make the tool less compact.
The handles of most screwdrivers are made of plastic with rubber inserts. For everyday tasks, this combination is ideal, but for work in contact with aggressive environments, it is advisable to opt for a material that is more resistant to their influence, such as plastic or wood.
On the back of some handles there are metal wrench heads - not an absolute necessity, but in some cases a very useful feature.
It is advisable that there is a hole in the handle, so the screwdriver can be hung on a hook or a cord can be pulled through it and hung around the neck.
Types of rods
The rods are installed in various modifications to increase functionality. They are produced in non-standard sizes in length - elongated and shortened; the same deviations apply to the handle, which allows you to position the tool for rotation in difficult places. Most often used in combination screwdrivers and models with a flexible rod.
Combination type universal rods are found in combination or ratcheting screwdrivers. If the screwdriver has a faceted rod, then it is used to increase the lever force, namely another improvised tool, for example, pliers.
Non-standard applications
It happens that you need to tighten something in a hard-to-reach place where only the shaft of a screwdriver can get through. And there is no special tool at hand that can hold the fastener. Then you have to resort to such a trick as magnetizing the tip. Then the bolt or screw will be easily held on the tip, which will allow you to deliver it and tighten it anywhere. The following steps will show you how to magnetize a screwdriver at home:
Using a magnet. A powerful magnet, preferably neodymium, is suitable for this. The stronger the magnet, the better the magnetization effect. You can buy the necessary magnet at the market or at a hardware store. If you have old computer hard drives at home, you can use the magnets in them. For proper magnetization, it is necessary to clean the surface of the rod from contamination and dry the surface after processing. Then you need to take the magnet and move it along the shaft of the tool from the handle to the tip, you need to do this several times, then turn the tool a quarter turn and do the same with each side. You only need to move the magnet in one direction. If, after completing the procedure, the tool is not able to hold the fastener, then the entire process must be repeated again. In case of repeated failure, it is worth replacing the magnet with a more powerful one. A tool made of good steel can hold magnetic domains for up to several months. If the tool needs to be demagnetized, then you can carry out the same procedure, but in the direction from the tip to the handle, or knock the tool on the floor or wall, which will help destroy the magnetic domains. Using a battery. For this method, you will need a small cross-section electrical wire with a length of at least one meter and ends stripped on both sides. A 2.5 square wire with single insulation is best suited. The ends of the wire are stripped, and the remaining unstripped part is wound around the screwdriver rod, thus forming a kind of magnetic field. Then take a battery or crown with a power of 6 to 9 volts (no less and no more), to which the stripped ends of the wire are connected. There is no difference where to connect the negative and positive contacts
It is important to know that it usually takes half to one minute for the tool to become fully magnetized. After this time has expired, the battery must be disconnected from the wires, the tool must be released and placed on the mount.
If magnetization is unsuccessful, you can try to increase the number of skeins, placing them in two layers on top of each other. Increasing the battery power can also help, but you should be wary of electric shock or sparks, so all manipulations should be carried out with dielectric gloves. There are also several options for magnetizing the instrument, which would most likely be considered amateur. You can magnetize the instrument using a silk scarf or synthetic rag. If you carefully rub the tip with a similar cloth for a long time, then for some period of time, the screwdriver will be able to hold a small bolt or screw. If you don’t have anything on hand that can magnetize the tool, you can use a hammer or a heavy wrench. To do this, you need to position the tool with the tip facing north and hit the tip for a long time. Thus, the magnetic domains are aligned in the direction of the Earth's magnetic field.
During all manipulations, it is necessary to adhere to certain rules so that neither the human body nor the instrument itself is damaged. When using a neodymium magnet, you should remember that it has a very powerful attractive force and can pinch part of the skin. All actions must be carried out wearing special dielectric gloves.
Types of handles
Screwdriver handles have also undergone considerable changes during the evolution of household and professional tools. They have become more comfortable, more powerful and stronger. And some have added complex elements with rotational mechanisms. In addition to the traditional types, there are also the following:
- Handle with heel. This type of screwdriver is characterized by the fact that the rod is located along the entire length of the tool and comes out from the reverse side. The concept of "heel" arose because the area that protrudes from the other side forms a thick projection that can be hit with a hammer. Used in dirty and rusty places where a screwdriver can be used as a chisel.
- Handle with ratchet. It works as an intermittent movement in one direction with a conversion of reciprocating rotational movement and a switch that allows you to change the direction of movement. Typically, such screwdrivers are produced with a set of various attachments, allowing the tool to be used on almost all types of fasteners.
- Swivel or T-shaped. Such a screwdriver is made in the shape of the letter T or with a hole in the upper part of the handle for additional leverage, which allows such a tool to tighten fasteners as tightly as possible.
Depending on the type of work, the inaccessibility of the fastening element, as well as the type of fastener itself, different types of attachments and sizes of screwdriver rods are used. From the miniature length of the rod, measured in millimeters, to the longest, several tens of centimeters. From a regular flat attachment to a hex ratchet. There is also a screwdriver with a flexible shaft for getting into hard-to-reach places.
