The largest drill bit for metal

A drill is a common cutting tool that is used not only to produce through holes by drilling, but also to increase the size of existing ones.

Technically, the products are attachments for hand drills, hammer drills and various machines.

Drilling itself involves removing material through the rotational movement of a sharp cutting edge.

The instrument is divided into a huge number of types according to its shape and purpose.

Drill characteristics

The main characteristic of any drill is its strength, which should exceed this indicator for the material being processed.

The tool, depending on the conditions of use, has different sizes and shapes.

The sharpening angle of the cutting part, color, etc. also differ.

Each product has a shank, the type of which must match the chuck of a drill, screwdriver or machine.

Material

For the manufacture of drills, alloys with different characteristics are used.

In this case, the so-called “high-speed” steel grades P18, P9, P9K15 are used.

If the diameter of the drill exceeds 8 mm, a welding method is used in its manufacture, for example: carbon steel for the shank, high-speed steel for the working part.

For materials with high hardness (mainly metal), cobalt drills are usually used.

Their peculiarity is that the working part is made from high-speed steel R6M5K5, VK6M with the addition of cobalt.

After the letter “K” in the marking there is always a number that indicates the amount of cobalt in the parts.

Carbide Pobedit drills are used for drilling concrete, stone and brick.

The tip of such a tool is tipped with pobedite, an alloy of tungsten (90%) and cobalt (10%), developed in the USSR. There are more than ten modern modifications of this alloy.

The pobedite tip does not cut the material, but crumbles it, so it is not suitable for working with metal, plastic and wood.

In addition to tungsten and cobalt, chromium, molybdenum, and vanadium are found in the alloys, and their percentage is indicated in the marking.

Coating

To extend the life of drills, their body has one of the following coatings:

• Oxide film – significantly increases resistance to overheating from friction.

Also protects the product from rust.

The service life naturally increases.

• Diamond coating is the most durable coating available.

It is mainly used on those products that are used when working with extremely hard materials, including stone and porcelain stoneware.

• Titanium coating is a general name indicating that the material contains a chemical compound of titanium - TiN (titanium nitride), TiAIN (titanium aluminum nitride), TiCN (titanium carbonitride).

Coloring

The color of the drill is very important.

It indicates the coating used or processing method:

• Gray is the native color of steel.

Indicates the absence of any processing.

The cheapest and most short-lived products are gray in color.

• Black is the color of steel that has been exposed to superheated steam during finishing.

Black products are much more durable than the previous option.

• Yellow is the color of steel that has been tempered (processing of metal to relieve its internal stress).

It speaks of the high hardness of steel, and its brittleness is greatly reduced by tempering.

• Golden – the color of titanium nitride. Bright golden tools are very durable, and they also have reduced friction against the workpiece.

Dimensions and weight

Manufacturers of cutting tools offer an impressive range of drills of every possible “caliber”, depending on the design and purpose.

Let's look at the most common spiral products according to GOST:

• Short: 20 – 131 mm in length, 0.3 – 20 mm in diameter (GOST 4010-77);

• Extended: 19 – 205 mm in length, 0.3 – 20 mm in diameter (GOST 10902-77);

• Long: 56 – 254 mm in length, 1 – 20 mm in diameter (GOST 886-77).

As for the exact weight, it depends not only on the design of the products, their sizes, but also on the material of manufacture.

The weight of ordinary twist drills usually ranges from several units to several tens of grams.

Processing accuracy

For twist drills there is such a characteristic as accuracy class:

• A – increased accuracy (10 – 13 qualifications);

• B1 – normal accuracy (up to 14 qualifications);

• B – normal accuracy (up to 15 qualifications).

Quality is a characteristic of accuracy that determines the tolerance values.

Review: Tungsten Carbide Micro Drills

The other day I received a parcel from Pittsburgh, USA, a box with 50 microdrills... Of course, it is not very patriotic to praise American industry, but considering how much I have suffered with microdrills throughout my entire modeling life, I think that politics can stand aside here, especially since that they are probably made in China)))

In general, in order. First, I will describe my problem, perhaps you have encountered it too. Often, even when assembling a model out of the box, not to mention conversions and building from scratch, we need to drill small-diameter holes in plastic or resin. For example, imitate a hole in the barrel of a machine gun, or drill sockets for small parts, or prepare holes for antennas. Well, in general, you can’t go anywhere without microdrills... If there are no problems with holes larger than 1 mm in diameter, then with microdrills themselves, with a diameter of less than 1 mm, the main problem is their fragility. What is available here, for example, “ZUBR”, is very fragile, apparently low-quality Chinese steel, I don’t know... But they break all the time, especially the thinnest ones: 0.33, 0.36, 0.40 mm. It is strictly forbidden to use them in a drill, and it is difficult to fix them in a collet clamp; they are very thin.

So I decided to try something more durable. On eBay I found products from Drill Bits Unlimited, large sets of 50 or more drills, 5 types of 10 pieces each, for example from 0.16 mm to 0.35. Very thin, something I've never seen before. Moreover, it is much more convenient to hold them due to the wide base and plastic attachment. This allows them to be conveniently mounted in both a hand-held collet clamp and a drill. But I would still advise you to be careful with a drill, even with such drills, they will still break, this is inevitable, especially with the one I have, Proxxon, which does not have low speeds.

Drill bits are made from tungsten carbide, which is much stronger than steel, and is used to make heavy-duty cutters, abrasive wheels, drills, cutters, and other cutting tools, as well as armor-piercing bullet and projectile cores. By the way, tungsten carbide has a hardness of 9 on the Mohs scale, only diamond is harder...

Let's see what this whole celebration of life looks like:

Here is a plastic box with a pull-out shelf in which drills are installed,

The box is designed so that when storing, transporting, removing and returning the drills to their place, they are not damaged:

5 rows of 10 drills: 0.16 - 0.20 - 0.25 - 0.30 - 0.35 mm

It is convenient to hold with your fingers; holes in thick plastic, 50 mm thick, are drilled in literally three turns, in a second. With a regular drill it would take ten times longer. They are also pointed, you don’t need to mark the holes for them in any way, bait them, etc., you just start drilling and that’s it, the drill doesn’t “crawl” around the plastic in circles...

It fits perfectly into the collet clamp, and of course it’s even more convenient to work with, but I think there’s a greater risk of breaking the drill

At 5000 rpm, my drill made about 20 holes in thick plastic in 5 seconds... The drill didn’t break, but it wasn’t the thinnest of them, so I didn’t take much risk:

In general, there is a huge selection, here are some sets:

You can order certain sizes separately, see for yourself

I believe that they can be made in China, and I plan to put together a small test order to bring inexpensive Chinese ones for comparison. because this set from the USA, including delivery, cost me almost 3,000 rubles... If anyone needs it, leave requests in the comments, I will contact you

Pavel Cherepanov

ost-front.ru

Types of drills

Products are divided into several groups according to design and purpose.

This allows you to quickly select a tool for specific tasks.

By shape

Based on the shape of the drill, it is quite easy to determine what material it can be used for:

• Spiral is a classic instrument.

The working part has two teeth, which are twisted in a spiral.

The tool, biting into the material, pushes the chips to the surface with its grooves.

The shape of the tip depends entirely on the material for which the tool is intended.

As a rule, the diameter of products does not exceed 80 mm.

• Screw - a modernized previous version, which has a more advanced form of grooves that remove chips.

Another difference is that such products are longer.

• Feather - a flat-shaped product, the cutting part is made in the shape of a sharp peak, the outlines of which turn into a wider blade.

Other names are flat cutting drill, which is dictated by its shape, feather drill.

Builders call it perka.

Used where you need to get a deep and at the same time wide hole.

• Annular – for those cases when you need to drill a hole with a large diameter without preliminary preparation.

More commonly known as a crown.

The shape of the tool resembles a hollow cylinder, and on the axis of rotation there is a centering twist drill.

The part that cuts the material is made either in the form of teeth, carbide tipped, or has a coating of diamond chips.

• Conical (tapered) – its shape resembles a cone with a sharp tip.

By purpose

The instrument is divided according to its purpose, which is the reason for its special shape in each specific case.

The following drills are used in construction, at home and in production:

As the name implies, they cope with most materials.

They have a special sharpening, which received the corresponding name - universal.

• For wood – these are spiral, feather, ring and screw.

Forstner drills and ballerina drills work well on wood, among others.

• For metal - conical, crown, stepped, as well as classic spiral.

• For concrete – crowned with carbide tipped, impact spiral and screw.

They have different shanks for hammer drill chucks.

• For ceramics – crowns, spear-shaped and ballerina.

The first ones are produced without teeth.

The cutting function is performed by a special diamond coating.

When working on glass, these are the types that are used.

• For plastic – special spiral options and crowns that can pass through the material without breaking it.

There is a specialized tool that is used strictly to perform a specific task:

• For deep drilling – a spiral tool with through channels.

Their purpose is to supply coolant directly to the cutting part.

This includes rifle and cannon subspecies.

• One-way cutter is a tool whose main purpose is to create precise holes.

Subtype - ejector drills designed for drilling machines.

As the name implies, the cutting edges are offset to one side of the axis around which the tool rotates.

• Centering – a specific tool capable of making only center holes in parts, but nothing more.

Among all the tools intended for metal processing, drills are in good demand both in everyday life and in production. The large assortment offered on the market by leading manufacturers confuses when it comes to choosing what suits best both in terms of price and technical characteristics.

Brief contents of the article:

Homemade drilling machine for thin drills

Homemade drilling machine for thin drills
Nikolay wrote:

I'm interested in a drilling machine... what brand is it and how much does it cost? I would very much like to see in the future an article dedicated separately to this machine, or rather to its detailed description and manufacturing process.

Responding to Nikolai’s request, I decided to describe the design of my drilling machine. Unfortunately, this machine is not a budget solution, since quite expensive components were used in its manufacture. https://oldoctober.com

The drilling machine in question was made many years ago in order to drill thin holes with a diameter of up to 0.3mm.

Once upon a time, in the era of matrix printers, when repairing matrix heads, it was necessary to drill fairly precise holes of small diameters.

When drilling printed circuit boards, of course, such thin holes are not needed, but drills with a diameter of 0.5 - 0.7 mm are also quite gentle and this machine can extend their life.

The highlight of this machine is the ADP-1262 asynchronous AC motor with a “squirrel wheel” rotor. The rotor of this motor is a hollow aluminum glass with a wall thickness of about 0.5 mm. The stator occupies the rest of the space. The stator has a narrow cylindrical slot in which the rotor rotates with a gap of a few tenths of a millimeter.

I do not recommend disassembling such an engine without sufficient experience in working with precision mechanics. One careless movement and the glass will be deformed, after which you can say goodbye to the engine. https://oldoctober.com

Naturally, the weight of such a rotor is so small that its inertia can be neglected, especially considering the mass of the clamping chuck.

In addition, the engine has a very smooth characteristic. As the engine speed decreases, the torque on the shaft also decreases. All this ensures the safety of thin drills when jammed and when the permissible torque on the cutting edge is exceeded.

A 6B10 three-jaw chuck is used as a drill holder, which allows clamping drills with a diameter of up to 6 mm.

The bed is assembled from two parts. The stand pos. 1 and the rack and pinion mechanism pos. 2 are borrowed from the MBS-1 microscope. The base of item 3 is cut from a steel sheet 10 mm thick.

The engine is secured with a clamp, which in turn is attached to the feed mechanism with four screws. The screws are indicated by arrows in the figure. The holes are located at the vertices of the square, so the engine can be positioned not only vertically, but also horizontally.

The cartridge is secured using a shaped bushing, on the outside of which a No. 1 cone is machined, and inside there is a hole machined for a transitional fit equal to the diameter of the engine shaft (6mm).

The bushing is turned on a lathe in one step. That is, during the turning of the cone and the turning of the hole (not drilling), the workpiece was fixed in the machine and only then cut off.

For reliable fixation and selection of possible misalignment, the bushing has six M3 threaded holes for locking screws. There are six recesses made in the motor shaft, into which these locking screws fit. The holes are staggered, which allows you to select misalignment even if it arises as a result of wear of the mating surfaces. The screws are secured with locking paint.

A flange with a slot is attached to the upper extension of the engine shaft, which, together with a bar fixed to the engine body, represents a locking mechanism. This mechanism allows you to tighten the cartridge without using a key (by hand).

The use of a key asymmetricizes the chuck clamping mechanism and leads to uneven wear of the latter, which can cause the drill to run out. When using thin drills with thick shanks, this can cause noticeable eccentricity of the working surface of the drill.

At the upper end of the engine there is a duralumin casing (marked with an arrow), inside of which there is a phase-shifting capacitor and an engine switch.

To control the torque on the motor shaft, LATR is used.

The motor allows the rated supply voltage to be doubled, which allows the use of drills up to 8 mm, with shanks machined up to 6 mm, when drilling thin sheet plastic, fiberglass and other materials, the drilling of which does not require large moments on the working edge of the drill.

Attention! The twofold excess was taken not from passport data, but from practice.

October 15, 2010 (22:12) in Do it yourself

oldoctober.com

Classification

There are the following types of metal drills:

Universal spiral, for any holes;
Conical type, designed for use in lathes, as they require increased control during operation;
Stepped shape. The cutting edges are of different diameters, which allows not only drilling holes, but also boring them;
Annular cutters or core drills. They are also used for processing wood; they are easy to work with; they can be used to produce holes with minimal roughness.

Drills are also classified by size (length/diameter of cutting edges):

According to GOST 4010-77 – short;
According to GOST 10902-77 – extended;
According to GOST 886-77 – long

Differences in the operation of an extra-long drill from a regular drill

Extra-long metal cutters are subject to more heat than ordinary ones. This is due to the large contact area of the tool with the channel walls and poor heat transfer due to the closed space. Therefore, it is necessary to organize forced cooling during drilling. An elongated drill has increased bending strength, but if you drill continuously, passing a channel at a time, then the probability of the drill breaking due to the metal shavings formed in the channel is very high

It is important to remove these chips from time to time by returning the tool back. Fast and continuous feed of the cutter can also cause destruction of the tool, so you need to go forward with short feeds. It is difficult to use an extra-long metal drill with a conventional electric drill: it is impossible to hold the tool perfectly level. The hole may turn out to be of poor quality, parallelism will not be maintained, and the probability of breaking the equipment is high

All this can be avoided by drilling using a special machine. To drill hard alloys, it is necessary to work at low shaft rotation speeds. This will prevent the cutting edge from overheating and becoming damaged. Sharpening of cutters for metal must be done using special equipment, strictly observing the angle. It is better to use a template for this.

Features of choice

For everyday use, it is better not to take a set of drills that will lie around idle, waiting in the wings. Also, do not buy Chinese counterfeits.

Professionals recommend buying drills based on the type of drill and hole diameter. You should not buy a cheap Chinese tool set for household use.

Better one thing – but of high quality – than a pack of unnecessary cheap hardware!

Spiral drills are ideal for this. The remaining types are used mainly in production, on milling, turning and cutting machines and other specialized production equipment.

Differences between conical drills

It is distinguished by a stepped structure identical to a cone. That is why the drill received the appropriate name. It has a smooth or stepped shape.

In fact, this is a universal tool that allows you to create holes of any diameter.
Can be used to enlarge holes based on thin metals up to 4 mm.
The end has a centering tip for drilling in the appropriate place without the need for shifting.

Important: Conical types of drilling element for metal have a diameter in the region of 4 - 32 mm.

Twist drills

They are used when you need to make a hole in various steel materials, cast iron, and non-ferrous metals. Their advantage is that they remove used metal - chips - through longitudinal grooves specially cut on their surface, symmetrically wriggling along the diameter of the drill.

They differ from other types of drills in the shape of their end part - the shank. He can be:

Cylindrical;
Conical;
Hexagonal.

Drills with a cylindrical shank are inserted directly into the quill of a lathe, while conical and hex drills are inserted through a special chuck.

The first type of working tool is not suitable for a hand drill, as it will rotate in the slots when drilling. The best option is with a hex shank.

In photo catalogs and color price lists you can see various sets of drills that differ in color, size and markings. These external data are important when choosing metal drills and affect their characteristics.

Read also: Intercom and calling panel connection diagram

What can the color of a drill tell you?

In addition to the markings indicating the composition of the steel and impurities, you need to understand what the color of the drill indicates. This will tell you what additional processing the metal has undergone and how this will affect the characteristics of the equipment. Here are the common types of colors.

Steel gray color

These are the simplest drills without additional coating. If they are left in a humid environment for a long time, they will rust. When drilling, do not put excessive pressure on the tool, otherwise the rod may break.

Golden tone

This color indicates that it has been hardened. The treatment makes the outer part very strong, but increases the internal fragility. Drills hold an edge for a long time, but are prone to breakage. To extend their service life, periodic re-hardening is required.

Golden bright color

Such drills are immediately noticeable on the counter with their bright color. The effect is ensured by titanium surface treatment. The coating reduces wear from friction and promotes long-term operation. The drills belong to the high-strength class and are priced accordingly.

Black color

The steel is steam treated. An inexpensive way to increase external strength while avoiding internal brittleness. The drills hold an edge better and last longer than the gray ones.

Characteristics

The technical parameters of manufactured drills depend on the color:

Black color - indicates increased wear resistance of the product;

A drill with a light golden hue means that the cutting tool does not have increased fragility; it was tempered during manufacturing to relieve internal stress;

Bright golden – the ability to reduce friction during operation, products are characterized by good strength;

Gray - the tool is designed for a short service life, the cheapest, of low quality.

Having remembered the color of the drill, we pay attention to the diameter of the working edge, which determines its marking. Small instruments (up to two millimeters) are not marked. The letter “P” is the very first letter, which means that high-speed steel was used in the manufacture of the drill.

The presence of alloying elements (titanium, cobalt, tungsten) will be indicated by the corresponding alphanumeric code adopted in accordance with GOST for marking.

All technical data about the drill can be read on its shank:

What is the diameter?
Learn about the hardness of steel;
What alloying elements are in the alloy;
Understand the technology, the manufacturer.

As mentioned, there are no markings on small diameter drills!

The most expensive, durable tool is made of cobald. Also, drills with USSR markings are most valued.

Selection principles

When choosing, you need to consider:

product color;
purpose of equipment;
quality of sharpening;
symmetry of incisors;
equipment material, type of protective coating.

Drills of different types (Photo: Instagram / koleso_ast)

Advantages and disadvantages

Advantages:

the ability to perform various technological operations;
strength, reliability, durability;
low price.

Manufacturers and prices

Manufacturers:

Bosch;
Haisser;
Ruko.

Gimlets with the USSR designation are considered the most reliable and durable. The price of a classic drill marked HSS is 500 rubles.

Bosch brand drill (Photo: Instagram / sergei.wood_man)

How to sharpen a drill

Drills are also selected according to their sharpening angle. This is the distance between the cutting edges. The sharpening angle depends on the material being worked with and its characteristics.

For example, for steel – up to 140 degrees, for stainless metals – up to 120.

The tool can also be sharpened independently if you have the appropriate equipment, knowledge, and experience. It is worth noting that a file cannot properly sharpen a drill!

A well-sharpened tool makes it easy to make holes without much effort.

Criterias of choice

Manufacturer	Popular manufacturers include: matrix, BARS, BISON, Enkor, Vira, STAYER,
Drill type	Two types (picture above) - with a spiral and a straight groove. With a straight groove - they have a simple geometric shape and are easier to sharpen. With a spiral blade - good smoothness, high cutting performance and better chip removal.
Number of steps	There are small drills with 3-6 stages, as well as multi-stage ones with 10 levels, which makes it possible to make 10 different holes in diameter.
Drilling diameter	It can vary from 4 to 12, from 6 to 30, from 4 to 40 mm, it all depends on the number of steps and the size of the working part.
Working part length, mm	57, 70, 76,, 81, 100, 105, 115 mm. Step 1, 2, 3 mm
Shank type	By type of shanks they can be divided into: hexagonal, cylindrical, triangular, canonical.
Shank diameter, mm	Ranges from 6 to 12 mm
Drill material	HSS (High Speed Steel) - high-speed steel drills, made from 3 types of steel: Tungsten (T1–T15), Molybdenum (M1–M36), High-alloy (M41–M62). HSS-G - the cutting edge is treated with cubic boron nitride, which extends the life of the drill. HSS-G TiN - containing titanium nitride. HSS-E - contains cobalt and other high-strength metals

Manufacturers

Every well-known brand offers reliable tools of a certain quality that you can trust. Among all the manufacturing companies, the following can be distinguished:

Quality at a reasonable price from Ruko;
The best drills from the famous brand Bosch;
High-power titanium alloy drills from the Haisser brand;
Reasonable price, excellent quality from the Russian brand Zubr.

When buying drills, you need to think about how long they will be used and what material they will have to work with. Chinese counterfeits are definitely not the best choice. But so is an expensive set that will gather dust on a garage shelf.

Based on expediency, needs, financial capabilities, you can always choose a good tool that will last for many years!

Not only specialists, but also home craftsmen often have to process various metal products. And here you cannot do without special tools, in particular drills. And here the question arises about which metal drills are the best and how to choose them correctly .

Differences between cobalt type drills

They are created on the basis of high-speed steel with cobalt alloying. This provides the drill with increased strength and stability during the cutting process. It is not susceptible to powerful thermal and mechanical effects.

Thanks to their advanced technical design, cobalt metal drilling elements are popular. They allow you to easily create holes based on the strongest metals or alloys.

It is worth highlighting the high cost, but it is justified by excellent performance characteristics.

Design and functional features

There are different types of metal drills, which differ from each other in functionality and design. Moreover, with the help of such devices it is possible to process not only the metal itself , but also other materials, for example:

Design features necessarily take into account the characteristics of the material that will be processed. When it comes to metal drills, they include such elements as:

cutting part - performs key work;
shank - with its help the tool is fixed in the equipment chuck;
working surface - it is used to remove chips from the processing area.

Overview of species

Long drills can differ significantly from each other in shank design. There are devices with cylindrical and conical shanks. The first are thin cylindrical metal rods. There are four grooves on their surface (2 screw and 2 spiral) - they are needed for cutting material and removing chips.

Straight drills are used for drilling steel, wood and non-ferrous metals. They can be left-handed or right-handed, but the first option is more common. According to GOST, these devices are manufactured with a centering recess, but some of them can be manufactured without it.

Cylindrical drills are sometimes made with a small neck, which makes them easier to grind. The total length of such drills can be up to 320 mm.

Models with a tapered shank are considered more preferable among specialists. They are securely mounted in the drill chuck, providing the most accurate centering during operation.

The conical type of shank allows you to avoid the appearance of burrs and irregularities on the material when drilling. The upper part at the end will be completely smooth, the walls of the drilled holes will also be smooth.

Conical-type devices have the most convenient design, which allows, if necessary, to replace them with a new model. Such tools are used for drilling metal. But they may be suitable for wood or plastic.

Using these drills, you can make holes of different diameters in alloy or carbon steel, cast iron, cermet alloys, and non-ferrous metals. The drill itself is fastened with a conical shank thanks to the adapter sleeve. Devices of this shape are produced with a spiral working part.

There are several varieties of long metal drills, which differ in strength, the part that is fixed to the equipment, the cutting part, and the working surface for removing chips.

Next, we will consider the most common models of elongated nozzles in more detail.

A polished version for metal with a conical shank. This type is suitable for working with products made of building and structural metal or cast iron. The drills are made of high-speed steel HSS and have a sharpening angle of 118º.
Cutters made of quick cutters contain an admixture of cobalt and are covered with a titanium-nitrite layer on top. Used when working with steel parts having the highest strength (900 N/mm²).
Extra-long and long elements for metal. They are equipped with cylindrical shanks and have a reinforced rod. To effectively remove chips in this version, a spiral groove in the shape of a parabola is made. This type of drill is characterized by increased rigidity.
A pointed spiral nozzle with a long or extra-long size. Has a cone-shaped shank. This option is used for drilling holes with both large and small diameters.
Drill bits for drilling hollow parts. They have a small cutting part.
A device for drilling holes in hard alloys. They have a sharpening angle of the cutting part of 135º and a cone-shaped shank.

Extended drills can be divided into several separate groups depending on the structure of the working parts.

Feather drills for metal stand out. Similar models are used for drilling deep holes of large diameter. They are equipped with centering sharpened tips. They also look like a small flat blade.
Core drills are of particular importance. These models can also be suitable for creating large diameter holes (it can be up to 150 mm). They are used to work on milling and drilling machines. The devices first cut out the outline of the future hole, and then make the depression itself on the surface.
There are models with a cone-shaped working part. These devices are used for drilling non-ferrous metals or steel. But they process metal sheets of small thickness, which should be less than 10 mm. They can be made in a standard design, or they can have a stepped design. The latter facilitate further processing of the metal.

Models with a conical tip allow you to make recesses of different diameters. In this case, there will be no need to regularly change the drill in the chuck. Such tools are perfectly centered.

Classification

Depending on the design, drills for metal products are:

Flat tools are distinguished by a flat shape of the working part ; they are also called feather tools. Their advantages are:

lack of sensitivity to distortions;
simple design;
affordable price.

However, they also have their disadvantages:

They cannot be used to drill large diameter holes.
There is no automatic removal of chips from the processed area.

Spiral tools

Twist type drills are the most common. Such a tool has the shape of a cylindrical rod, the assembly of which contains spiral grooves covering its entire working part. Thanks to them, chips are removed from the working area.

Depending on the design and scope of use, spiral instruments are divided into:

Cylindrical - have a general purpose. The diameter of the tools can reach 80 mm; they can be used for both home and industrial purposes.
Left-handed - have a limited scope of use. They are needed primarily when you need to drill a bolt with a broken head or a fastener from a threaded hole that cannot be unscrewed in any other way.
Tools of increased precision - they can be identified by the presence of the designation, A 1. With their help, you can make holes with the most accurate diameter.

Core and cone drills

Crown tools have the appearance of a metal glass . On its end working part there are cutting teeth, with which you can make holes with a large diameter. Such teeth can be diamond-coated or made from hard alloys.

Conical products have a stepped and smooth working surface and are used to create holes of small thickness. They are able to provide easy centering of the hole at the beginning of work. Their key advantage is the ability to make holes of different diameters .

There are also other types of tools, thanks to which even the most highly durable materials can be processed. These are cobalt or carbide tools.

Cobalt tools are made from high-speed steel that has been alloyed with cobalt. This material gives high strength to the drill, thanks to which it is resistant to thermal or mechanical stress and deformation. They can be used to drill even high-strength and tough metals or alloys. The only drawback is the high price, which is compensated by technical characteristics.

If we talk about carbide structures, they differ in that carbide plates , and the main part is made on the basis of tool steel. The plates are made on the basis of carbide alloys, which have high wear resistance and hardness. The cutting inserts will not need to be sharpened in the future, and with the help of such a tool you can drill particularly hard metals or alloys, as well as products with great thickness.

Drill classification

Today, there is more than one classification of this tool that cuts almost any surface.

Depending on the design of its working part, we can distinguish: spiral types of drills for wood, centering ones, as well as flat and even drills with exclusively one-sided cutting, and used only for deep drilling.

If you look at photos of wood drills, paying attention specifically to the design of their tail part, you can distinguish the following types:

conical;
cylindrical;
3,4,6-sided;
SDS drills.

Also, all tools can be divided into several groups, based on the type of material they can process. So, these are long wood drills, as well as drills for hard concrete, glass, high quality metal, stone and ceramics, as well as universal tools.

How to choose a drill for metal

When choosing one option or another, you should know in advance where you will use it, and also take into account the characteristics of the material being processed. When purchasing, consider the following tool parameters:

quality of sharpening and symmetry of structural elements;
color;
functional features;
material characteristics;
working diameter;
compliance of the form with standard parameters.

Read also: Measuring the liquid level in a tank

When purchasing a metal drill, you need to take into account the features of the equipment with which it will work. For example, if you need to drill a large hole in a metal product, you need to take a powerful low-speed drill.

Surface color characteristics

The quality of products largely depends on the color of the surface. What does this or that color mean?

Gray - such a tool is inexpensive and is not of the best quality. It has not been subjected to additional treatments to help increase its hardness and resistance to burning or deformation. When drilling hard metals, such a drill may not be enough even for one hole.
Black - the tool was treated with superheated steam, has increased strength and wear resistance. The cost is higher than the previous option, affordable for most buyers.
Light golden - after manufacturing, the tool was subjected to a tempering procedure, during which residual stresses inside were eliminated and strength characteristics were improved.
Bright golden – these instruments are the best, they contain titanium. During operation, the level of friction is reduced, thanks to which the service life is long. The disadvantage is the high cost.

When purchasing a drill of a particular shade, think about how often you will use it, and also take into account the requirements for quality and accuracy of work .

So, if you plan to use them frequently and intensively for high-quality and precise work, then it is better to purchase bright golden models.

But if you buy cheaper options for this, then you will have to change them often, and in the end you will not save anything.

Dimensions

Manufacturers of these tools produce them in a wide range in terms of working sizes. But to make it easier to understand them, you need to be able to distinguish them by series:

short series (length ranges from 20 to 131 mm, and diameter from 0.3 to 20 mm, respectively);
elongated (length 19–205 mm, diameter 0.3–20 mm);
long (length 56-254 mm, diameter 1-20 mm).

Marking

Its labeling, which is not so difficult to understand, will also help you choose a particular product. Depending on the working diameter, it contains the following information:

If the instrument has a diameter of up to 2 mm, there is no marking.
For models with a diameter of 2-3 mm, it includes information about the steel grade and cross-sectional size.
If the diameter is more than 3 mm, then the marking includes data on the steel grade, working diameter and an imprint of the manufacturer’s logo.

This or that alphanumeric designation of the material grade indicates not only the category of the alloy, but also the presence of additional components in it .

For example, the letter “P” means that the product is made from high-speed steel. If there is a letter “M”, then this indicates that the composition contains molybdenum, and “K” indicates the presence of cobalt. These additional substances are designed to improve the performance of the product.

Foreign manufacturers include more information in the labeling; in particular, the labeling indicates the following:

country of origin;
trademark;
alloy grade;
working diameter;
accuracy class;
brief recommendations on materials that can be worked with with this tool.

Features of foreign markings

So, if we talk about the last point, which indicates the presence of recommendations on what materials are best processed with one or another tool, then such markings on foreign models are deciphered as follows:

HSS-R and HSS-G - the product is recommended for processing steel products made by simple casting or injection molding, and those made on the basis of alloy or carbon steels with a strength of up to 900 N/mm 2, things based on metal alloys ( containing copper, zinc, nickel, aluminum, etc.) billets based on malleable or gray cast iron.
HSS-G Co 5 - recommended for drilling metals with a strength of up to 1100 N/mm 2. These include stainless, carbon, alloy, thermally enhanced and heat, acid or heat resistant types.
HSS-G TiAN/TiN - the working part of such products is coated with titanium, aluminum and nitride. This increases their resistance to wear and corrosion, and the tools themselves can be used for processing metals with a strength of up to 1100 N/mm 2. This includes malleable and gray cast iron, copper alloys, and steel blanks made by casting.

Drill marking

To drill through stainless steel, you must use special equipment.
Any drills, including those for stainless steel, have certain markings. It indicates the technical characteristics, material and size of the equipment. Basic designations:

The letter “M” indicates the presence of molybdenum in the product. Its percentage is indicated by the number following this letter.
Letter “P” - the equipment is made of high-speed steel. The percentage of tungsten is indicated by a number.
The letter “K” indicates the presence of cobalt in the alloy. Its quantity is indicated by a number.

Foreign manufacturers make HSS markings, which contain information about alloying components and their quantities:

HSS-TiN - titanium coating is applied to the surface of the tooling during production. Thanks to this, the strength and wear resistance increases. Technical characteristics do not change when heated to 600 degrees Celsius.
HSS-E - contains cobalt.
HSS-E VAP are special drills designed for drilling stainless steel of different thicknesses.
HSS-R - drills with increased strength. Used for drilling bronze, cast iron, brass, cupronickel.
HSS-4241 is a tool designed for working with aluminum workpieces.

Which metal drills are better?

After reviewing the markings and characteristics of metal drills, let's move on to popular brands that are present on the market. It is no secret that the service life and quality of work largely depend not only on the characteristics of the product, but also on the manufacturing company.

Experts advise paying attention to the following brands:

Brands from the CIS countries are highly durable and reliable, resistant to wear and have an affordable price compared to foreign analogues.
Ruko - products can have a cross sharpening and different types of coating; they can be called the best example of the relationship between price and quality of products.
Bosch - this brand speaks for itself.
Haisser - products of this brand have their own design features; special alloys are used for their manufacture. All this allows it to be successfully used even under extreme loads.
"Zubr" is a Russian brand that offers high-quality and reliable options at an affordable price.

Advantages of step drills

Versatility (including drilling, chamfering, cutting and grinding);
Eliminates the need for a centering tool;
High drilling speed;
There is no metal deformation when drilling;
A good option for drilling holes of larger diameter;

The disadvantages include: a higher price, especially for professional drills, it is not easy to sharpen correctly at home, and it is difficult to adjust the exact diameter value.

Preliminary test of step drills. (To be continued)

Find out which drill bits are best for drilling metal

Rules for sharpening

If the cutting part of the drill is dull, then it needs to be sharpened. Please follow these recommendations:

Check whether the sharpening device is working properly and prepare a container with coolant.
When sharpening, press the tool tightly against the grinding wheel, starting processing from the back of the cutting edge.
The processing angle depends on the material of manufacture. For steel it is 140 degrees, for copper - 100, and for copper alloys - 120 degrees, respectively.
As a result of the work, the entire cutting surface, including the side, must be processed.

Since there are so many different drills for processing metal products on the market, sometimes making the right choice and avoiding mistakes in work can be extremely difficult. This material will allow you to choose the right tool option.

Mini drill 12 volts with a set of drills

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Greetings!
I present a review of a useful device - a small but powerful drill with a collet chuck. It is stated that it works on 12 volts, but it works fine on 5 volts. Details, many photos, measurements, examples of drilling vandalism, as well as a comparative video below. The packaging is very modest. Engine Plus is where the point is. Collet chuck. The collet is part of the chuck. Plus - versatility. The downside is that if you use drills from the minimum diameter to the maximum, then I think the jaws will eventually break off. The flask with drills did not survive the difficulties of postal delivery. Drills 0.8/0.9/1.0/1.1/1.2/1.3/1.4/1.5mm, two pieces each. Shaft 2.4 mm. The casing can be removed from the engine. The drills were placed in such a box. As it turned out later, the option is not the most successful - when turned over, the smallest drills slip between the compartments. But it'll do for now. Let's check the diameter of the drills Hidden text

With a collet on the shaft The smallest drill The largest is 1.5 mm. It's hard to put in and even harder to take out. I'll solder the wires. I'll connect it first to a universal power supply. These convenient plugs with terminal blocks will help me. Current consumption in idle mode In operation The drill is crazy)) And it heats up noticeably Vandalism Now I’ll solder the USB plug and power it from 5 volts Sources of five volts The universal power supply works fine Video Now I’ll try from the chargers One charger reacts to the interference created by the drill and does not work A the second is normal Five-volt vandalism It definitely didn’t work any worse, so you can power it from five volts. You just need to find a power source that does not respond to interference from the engine. As a result, we have a pretty good drill. The included drills aren't the worst. The textolite drilled a lot and didn’t dull anything. One drill actually choked on the south bridge on the motherboard)) That's probably it)) Thanks for your attention! Planning to buy +104 Add to favorites Liked review +67 +144

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