How to choose bits for an electric screwdriver

In order to choose correctly bits for an electric screwdriver, it is necessary to take into account several parameters. Not only the size of the bit matters, but also its robustness and additional features.

Bit type

Electric screwdriver bits are divided into several varieties. There are different types of bits:

  • cross-shaped;
    choose, bits, electric, screwdriver

    Cross-shaped tooling is the most popular

  • Flat or straight; Flat bits should be chosen for screwing screws with a notch for a slotted screwdriver
  • Hexagonal; Hexagonal varieties are most often used for furniture assembly
  • Star-shaped. “Asterisks are used for household appliance assembly and automotive applications

If you have to use an electric screwdriver regularly, it is better to choose a set that contains different types of attachments.

Tooling sizes

The most common choice is for 1/4-inch diameter fasteners. they will work with most fasteners. Knob lengths typically range from 25-250mm. Medium-sized bits are the easiest to work with. But sometimes it is more reasonable to choose the longest tips as they help to reach hard-to-reach places.


The so-called “gold-plated” elements with titanium nitride sputtering are considered the most durable. The accessories are characterized by high wear resistance and are well meshed with screws, do not fray and do not corrode.

Additional features

Magnetised bits are ideal for furniture assembly and other work. They sit securely in the chuck of the electric screwdriver and do not slip out of the metal fasteners. They are not recommended for use only in the case of electrical appliances that are sensitive to magnetic fields.

A useful option for the bit is a mechanical retainer in the form of a spring-loaded ball. It fits even more securely in the chuck than a magnet.

How to choose a bit for an electric screwdriver for self-tapping screws

Before selecting bits for self-drilling screws, you must first learn about the characteristics of the fastener. The type of bit should match the screw heads. Use flat bits for slotted screws, cruciform bits for crosshead screws, and so on.

It is important to ensure that the dimensions of fasteners and accessories are exactly the same. If the bit is too big, the screwdriver will not tighten properly. A small tip also makes tightening the screws more difficult, and can be chipped in the process.

How you can tell if a bit fits the tool?

What material to choose and where to buy a quality bit?

An important factor when buying a bit is the type of material it is made of and whether it is coated or not. if so, is it capable of withstanding the effects of the environment for a long time??

In retail outlets there are also bits with a coating made of titanium, which are the most durable and long-lasting of all the bits on the market.

3 general rules for the selection of electric screwdriver bits

  • Choose a trusted and reliable store for your purchase. Choose expensive specialist stores if you want good quality bits with a long lifetime guarantee. Don’t buy cheap bits from small and unverified outlets. Their quality may leave a lot to be desired. You may, of course, buy such goods in case you need them only for one or two times.
  • Look carefully at the material and its properties. Molybdenum and chrome alloys are considered the most reliable. you should avoid buying steel bits because they are not very durable and you will not be able to work with them quickly and efficiently.
  • pay attention to whether the bit you buy has a protective coating or not. Quality is excellent when titanium coating is on top.

Rarely used bit types for screwdrivers and screwdrivers

Now for the less common nozzle types:

  • With square spline. Marked R, Robertson. Not suitable for home repairs, intended for more specialized work.
  • Square. Sizes 0, 1, 2, 3. There are two kinds: standard and extended, 5-7 cm.
  • Vandal resistant Spanner Head. Marking SP. This bit also has other names: snake eye, fork head. It has two parallel pins with a circle at the base.
  • With a flat, forked slot. GR marking, size standard. GR4, 6, 8, 10. The nozzles are made of strong, high-quality steel and are long-lasting. Beside the standard model, there is also an extra long model, 5-10 cm.
  • With three blades. Marking TW, fully Tri-Wing. The tip has three straight blades. This element is mainly used in electronics, astronautics. Sizes. TW1, 2, 3, 4, 5, 6.
  • With four blades. TS marking, entirely Torq-Set. TR. sprocket with four spline in the center; Similar to previous type, only one more blade. Sizes. 4 to 10.
  • Pin-on-Hex. Hexagonal slot with rod in the middle;
  • TR. sprocket with pin in the center;
  • Triple Square. multi toothed slot;
  • Polydrive. looks like a star with 6 blunt square ends;
  • One-way or CL. Two quarters of a circle: one at the bottom left and one at the top right, or adjacent to each other at angles;
  • Eight- and twelve-sided in the form of a star;
  • Twelve-pointed sprocket;
  • Bristol gear spline.

How To Use a Screwdriver Bits With Drill (Correctly)

Types and characteristics of bits for electric screwdrivers

Work with many fasteners. screws or self-tapping screws. requires mechanization. Otherwise, no productivity can be achieved and the quality of the fastener tightening will drop as you get calluses on your palms. The invention of the screwdriver and its replaceable accessories changed this situation and made the process of joining parts more effective and stable. The procedure is no longer dependent on the condition of the worker and greatly accelerated.

The advent of different types of slotted joints demanded a quick change of bit heads, and this finally determined the design of modern screwdrivers. Today there are many kinds of interchangeable tools. It is not easy to choose the best variant, because it is necessary to take into account peculiarities and specifics of work of different types of bits. Let’s take a closer look at them.

During the selection, you need to pay attention to important details:

  • Choosing a store. If you want a good quality product, the best bet is to go to a construction store. There, if necessary, will consult on what bits are better to choose, and will give a guarantee on the goods. You should buy them at the market or in a hypermarket only if you are going to use them a couple of times.
  • Material. What the working part is made of affects its durability. if you need a bit to last a long time, it is better to choose from three types of alloys: chrome and vanadium, molybdenum and chrome, tungsten and molybdenum. You should not buy steel bits, because they are not durable at all, and it will be difficult to work with them.
  • Protective coating on the working tool. A bit with a special protective coating ensures that it will last a very long time. Options for protection are: titanium, diamond, nickel. Also, tungsten and nickel alloys are good for protecting the surface of the piece. The first material will provide strength, and the second will protect against corrosion.

What are bits for a screwdriver and how to choose the right one?

The screwdriver is an in-demand and versatile tool that is actively used for domestic and professional purposes. Despite the name, it is mistaken to think that this device is designed exclusively for tightening screws and self-tapping screws.

In reality, the functionality is much broader. And it depends on which bits are used.

The most popular kinds of bits are. That’s how you can use a screwdriver to tighten screws of all kinds. It is therefore necessary to understand what bits are, how they differ, what materials they are made of, and so on. it helps to make the right choice and purchase the necessary bits for the planned types of work.

Materials and coating

The alloy material of which the bit is made is a guarantee of its durability or, on the contrary, of its soft construction, in which if the specified forces are exceeded, it is not the fastening element that breaks, but the bit. Some demanding connections require precisely this strength ratio.

Cordless screwdriver drill. what to look for when choosing a tool?

However, in the vast majority of applications, the user is interested in the maximum possible number of screwing screws with one bit. Various alloys and steels are used to produce strong bits that do not fracture from the brittleness of the alloy and do not deform at the most loaded touch points. These include:

  • R7 to R12 high speed carbon steels;
  • S2 tool steel;
  • chrome vanadium alloys;
  • tungsten-molybdenum alloy;
  • Chromium-molybdenum alloy and others.

Special coatings play an important role in bit durability. For example, a chrome vanadium layer protects the tool against corrosion, while a titanium nitride layer considerably increases hardness and wear resistance. Diamond coating (tungsten-diamond-carbon), tungsten-nickel, and others have similar properties.

The titanium nitride layer on the bit is easily recognized by its golden color, the diamond layer by the characteristic shine of the tip of the stinger. Metal or alloy grade of the bit is harder to find out, the manufacturer usually does not give or even hides this information in the commercial interest. Only in some cases is it possible to apply the steel grade (S2 for example) to one of the facets.

The most common self-tapping bits can be roughly divided into two categories of cross-shaped products.

Phillips bits (PH)

No additional notches visible on the screwdriver and the bit itself, the design is simpler. Depending on the size of the cross slot, these bits come in PH0, PH1, PH2, PH3 and PH4. Cross bits number 2 are most commonly used on wooden and metal objects. PH3-4 bits are mainly used on bigger objects or for repairing vehicles.

Cross bits and other bits can be slightly different, not only in size, but also in shape or coating. In order to avoid confusion, you have to pay attention not only to the PH marking, but also to the part number. If 000 is indicated on the product.0, then you have the classic PH cross-head bit. Numbered 160.0 also makes a classic Phillips bit, and the symbols are 701.0 indicates a geometry called Exaform and a titanium carbide coating. Model 706.0 just have a stronger coating with a standard nozzle shape. If the bit is coated with Tin (titanium nitride), article number 101 is the right choice.0.

Useful at! The Tin coating is easy to identify by the golden color of the bit. bits of this kind are distinguished by their extra strength, durability and price. Available in lengths from 25 mm to 250 mm.

As a rule, products with a reinforced facing are more expensive and only available in a limited size.

Pozidriv (PZ) bits

Bits of this type are regarded as advanced, because in addition to the standard cross shape they have additional facets with intermediate notches. Bit type PZ2 should be selected accordingly for screws with additional notches and marking 2. PZ bits are mainly used for galvanized screws. Pozidriv bits are available in three sizes.1, 2 и 3.

This type of bit also has different article numbers:

Useful at! To determine that the bit is the right one for the self-drilling bit, all you need to do is connect the two elements. If the products are suitable, the fastener will not fall off.

If you fit a PH2 bit to a PZ2 self-tapping screw, the slot will break off very quickly. Accordingly, not only the dimensions are important, but also the type of bit and screwdriver itself.

Useful at! Self-tapping screws with a press washer for joining soft objects (for example, used in the construction of greenhouses) also come with a head under the PH and PZ.

Bits are available in regular and extended versions. The latter are useful if you want to drive a screw in a place that is difficult to access and cannot be reached with an electric screwdriver. These bits are usually up to 150mm long, which means they can be held in the hand like a normal screwdriver. As a rule, lengthened models are also not available in all sizes, but only in the most popular, that is. 2 and 3.

Bit and socket guide. Marking of all sockets and bits

Individual tool kits have more than a hundred different bits and sockets. But how many of them can you use at home or in your workshop?? Some of these are not at all like the bits and sockets you use in your home or construction site, because they are designed for specific industries, such as the furniture industry, specialized auto repair shops or home appliance and electronics repair shops. In this manual we describe what bits and sockets are available, so you can find out what’s worth buying and what bits you’ll never need in your life.

Straight Slotted Bits (SL)

The straight slot (SL) is a simple recess for a flathead screwdriver. It looks like a slot made in the head of a screw or self-tapping screw. A distinctive feature of the straight slot is the small contact area of the tool with the fastener (when you rotate the bit or screwdriver, its edges only touch the inner surface of the slot at two points). The SL (or Slot) slot is therefore not at all suitable for high-torque screwdriving applications. Despite their simplicity and versatility, these days they are used less and less often (mainly for tasks that do not require much torque).

Slotted bits can be found in almost every bit kit, including the most budget-friendly ones. These are marked with the letters SL and the numbers indicating the width of the blade in millimeters. in everyday life, it is useful to have at least two to three bits between SL4 and SL8 (and usually only specialists need flat-head screwdrivers of smaller and larger sizes).

Cross-head bits (PH, PZ)

Phillips head screwdrivers were first introduced in the 1930s when the characteristics of flat head screws became unsatisfactory for the machinery industry. The Phillips slot in the head of the screw or self-drilling screw allows precise tool centering, and the four contact points between the Phillips screwdriver or bit and the inner surface of the slot allow increased torque to be transmitted. That’s why fasteners with Phillips head slots can be tightened with much more force without the slightest fear of “slipping off” the head or damaging the tool.

There are about a dozen varieties of Phillips, but in practice only two are used: Phillips (PH) and Pozidriv (PZ).

The PH cross slot was specially developed for pneumatic and electric screwdrivers. It looks like a “Phillips” slot with a slight thickening in the center. Relevant bits and screwdrivers are identified with the letter PH and the digits indicating their size: 0000, 000, 00, 0, 1, 2, 3, and 4. Bit sizes PH1 to PH3 are the most common size in sets, and the others are only needed for more specialized tasks.

The PZ cross slot is visually different from the PH. There are additional “whiskers” on the head surface of the Pozidriv bits and their corresponding “ribs” on the PZ bits. These extra elements allow even more torque to be transmitted than the PH. Screwdrivers and bits of this type are marked with the letter PZ and the numerical symbol for the size: 0 to 5. The most useful in the economy is a bit PZ2 (almost all self-tapping screws of Pozidriv type, which you may encounter in everyday life or at construction, will be exactly of this type size).

Although they look similar, Phillips bits of different standards are not perfectly interchangeable. The fact is that the facets of the Phillips slot are slightly beveled at a slight angle, and the inner surfaces of the cross slot of the Pozidriv standard are vertical. Because of this feature, the tool of PH type has a tendency to be pushed out of the slot when the torque is high, while the PZ bits do not have this disadvantage. For this reason, although PH bits can be used to tighten PZ fasteners (and not vice versa), it is better to use the right tool for each type of fastener.

Square and hexagonal bits (SQ, Hex)

Four- and hexagonal splines appeared as an alternative to cruciform splines when it became necessary to increase the torque when tightening screws without increasing the size of their heads.

SQ (Square) Robertson bits have a square tip. They are marked with a number that denotes their size (from 0 to 4). Screws and self-tapping screws with square slots are not common, but you may need SQ bits if you are involved in car repair (especially Canadian-made) or carpentry. The most useful sizes of square bits are SQ2 and SQ3.

Hex (Hexagon, Allen) Allen bits have a working section in the shape of a regular hexagon. Suitable fasteners are used very extensively, particularly in the furniture industry. Even conventional plastic windows can be adjusted with hex bits (but special extended wrenches are usually used for this). Bits of this type are identified by the letter H and a number indicating their size (distance between opposing faces). In everyday life, the most useful and popular tools are those of size H3 to H6. There are also Hex “anti-vandal” bits (Hex Hole, Hex Tamper Resistant or Hex Tamper Proof) with a hole in the center.

Star-shaped bits (T, TX, TH)

Star-spiked fasteners and fastener tools have been in circulation for over 50 years since complex machines and robots appeared on automotive assembly lines. The star shape greatly increases the contact area between the bit and the slot. This makes it possible to tighten the fastener with very high torque without damaging the head or the working edges of the tool. There is almost no tendency for the bit to knock out of the slot so the screwdriver or electric screwdriver does not have to be pressed axially during operation.

These days you can find “star” fasteners everywhere from laptops to cars. There are a few different standards, but the most common is the regular Torx (depressed star shape with six rays) and its “anti-vandal” version Torx Security (in the exact middle of the slot is a small protruding pin, to work with such fasteners need a bit with an appropriate size hole).

Torx bits are marked with the letter T (some manufacturers use TX letters) and a number that indicates their size, from T1 to T100. The most common sizes are T10, T15, T20, T25 and T30. Smaller bits (T2 to T4) are only needed by those who repair computers and home appliances. Torx Security bits (also called Torx Hole or Torx Tamper Resistant) are marked as TH (sometimes TR), and their size range is identical to Torx bits. The Torx Security tool can be used to work with Torx fasteners (but not vice versa).

Bits for Apple equipment (P)

Screwdrivers and bits designed for tightening and loosening screws with five-pointed star points with rounded edges became popular a little more than a decade ago thanks to Apple. And that’s when the Pentalobe standard anti-vandal fastener began to be used for assembling MacBooks, iPhones and iPods. Toolmakers immediately began manufacturing screwdrivers and bits to fit this rare standard, and now it’s easy to buy bits for disassembling Apple products.

In tool catalogs, Pentalobe bits are designated by the letter P and a number indicating the size. Anyone repairing electronics may need tools in sizes P1 through P6. Note that some bit manufacturers use a different letter designation (TS or PL) and the size range of these bits is not the same as Apple’s (for example, P2 is TS1 and P5 is TS4). Also Pentalobe bits should not be confused with the five-point Torx bit because they are completely different standards and not compatible with each other.

Rare and special bits

In addition to bits and bits that are necessary for working with common flat, cross and star slots, there is a large number of special bits that are used for screwing and unscrewing rare types of fasteners.

Spline bits have a working part in the shape of a twelve-pointed star with a 60° angle at the apex of each point. This design enables very high torques to be transmitted. For this reason, 12-beam sprocket bits are used where the highest possible tightening torque is required (e.g. in the automotive industry for engine assembly). Marking of Spline bits indicates size of fasteners they are designed for (from M5 to M20). Twelve-way stars should not be confused with “double hexes” and “triple squares” (XZN). Although they all have the same number of blades, they are incompatible because of the different profile geometry.

Tri-Wing bits are bits with three blades, each slightly off-center of the slot. The advantage of this design is that it transmits torque without axial pressure. The Tri-Wing fastener used to be used only in the aerospace industry, but in recent years many appliance manufacturers have used it as an “anti-vandal” protection from users. So you may need the TW0 to TW5 size three-headed bits for disassembling and assembling certain appliances and electronics (and the TW6 to TW15 size large bits are only good if you’re an airplane service mechanic). You might sometimes confuse Tri-Point (or Y-Type) bits with Tri-Wing bits, which also have three faces, but the blades are not offset in relation to the slot.

Torq bits (Torq-Set) are off-center, four-bladed cross bits. This slot is extremely rare (mainly in aviation), but can sometimes be used as an “anti-vandal” solution. Torq bits are marked with the letters TQ and a numerical symbol indicating their size (from 0 to 10). Some tool manufacturers use the letters TS.

Triangle bits are bits with a regular triangle-shaped working profile. Screws with a triangular slot are not often used, but are sometimes used to access the motor or battery door of appliances. Triangular bits may be identified with the letters TR or TA. The most common sizes are TR2 and TR3.

Clutch bits are used for tightening and loosening butterfly and hourglass screws. This type of fastener is rarely used in Europe, but it is much more common in the U.S. Clutch bits are marked with a letter C and a number denoting the size: conventional (like C1 or C3) or in inches (for example, C1/8″ or C5/32″).

Spanner bits are forked keys with two pins. Screws of this standard are used for security against unauthorized access. They are used to fasten elevator panels or close access to electrical panels on trains and in public places. Spanner bits are marked with the letters SP and a number indicating the size (from SP1 to SP10). This tool goes by many names. Manufacturers may refer to these bits as U-type, Snake-Eyes, Two-Hole, Twin-Hole, or Pig-Nose.

Hook bits are quite rare attachments. Not every set contains them. There is no unified standard for hook screw bits, so they look different from manufacturer to manufacturer. Such bits may look like the letter Y with a groove covering the hook surface, or be made like a cylinder with a cross-section slit.

Hex sockets

Hex sockets are the most common type of socket head. Their profile ensures good coverage of bolts and nuts. The range and markings are exactly the same as those on conventional wrenches. Standard heads have a depth of at least 25 mm, and extended heads have a length of the working part from 50 mm. Smaller sockets usually have a 1/4″ square drive (but as the tool’s working size increases, so does the mating section: 3/8″, 1/2″, 3/4″ and 1″).

Twelve-point sockets

The twelve-point sockets are, as the name implies, shaped with twelve working faces. They have a more precise and comfortable positioning on the fastener, because the 12-point socket can be rotated only 30° (in contrast to 60° for the 6-point socket). But there is a disadvantage: due to the reduced contact surface, sockets with 12 facets are more prone to “sticking” in bolts and nuts, especially when it comes to small-sized fasteners. The size grid of the twelve-point sockets is completely identical to the hexagonal sockets.

Surface / Super Lock sockets

Surface or Super Lock sockets correspond in size to the hex sockets, but differ in their profile. Their inner surfaces are not straight, but slightly convex. That is why the head does not turn at the very corners of the face of the fastener, but slightly in the middle. This design feature makes it possible to use Super Lock heads to tighten and unscrew slightly “bent” or deformed bolts and nuts.

Torx sockets

Torx sockets (sometimes called E-heads) resemble bits of the same name. The inside surface of the tool has a hexagonal star shape. It is impossible to use Torx bits for ordinary hex fasteners, but they are perfect for fastening and unscrewing E-profile bolts and nuts, which are used more and more often these days in construction of cars and some other types of equipment.

Spline sockets

Spline sockets are the most universal type of socket. They have alternating straight and rounded edges that (if the head is properly sized) provide good contact with various types of fasteners. With the Spline socket kit, you can turn common hex bolts and nuts (not just metric, but also inch) as well as Torx fasteners and even three-, four- and twelve-sided fasteners.

Understanding Basic Screw Bit Types

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