All About Cobalt Drills

Marking and color

All cobalt drills are carefully marked. First of all, they write the conditional letters of the elements, and after them indicate the percentage. Almost all steel grades are indicated with an indication of several alloying elements. The most advanced brand P6M5K5 means:

• tungsten - 6%;
• molybdenum - 5%;
• cobalt - 5%.

It is worth noting that tools smaller than 2 mm do not always have such details in the marking. Most often, the designation of the chemical composition is practiced on drills with a cross section of 2 to 3 mm

But, in addition to marking, it is necessary to take into account the colors of the products. To an experienced eye, she will tell no less than a combination of letters and numbers. The combination of black and gold colors indicates the passage of "vacation". This variation of heat treatment allows you to cope with internal mechanical stresses. The pure gold color shows the addition of not only cobalt but also titanium nitride.

This component helps to make the steel stronger. The friction level during operation will be less than usual. Black drills are produced by processing with superheated steam. This effect reduces natural technical wear and tear. The gray drill should be considered last - this tone indicates that there was no finishing treatment, and therefore the quality of the products will be quite low.

Marking and color of drills for metal

what is meant by marking

The efficiency of work with a drill is achieved due to the fact that high-quality and high-strength steel is used as a material for it. But cheap options that are produced on the basis of raw materials are not able to cope with most of the tasks that many owners face.

What does the drill mark mean?

Usually, the marking of a drill for metal contains a certain set of letters and numbers. The first is usually the letter of the main element, followed by a number that corresponds to the percentage of this element in the material used for the production of the drill.

Other elements are often listed after the first two characters.

• P - corresponds to tungsten;
• K - indicates cobalt;
• F - means vanadium;
• M means molybdenum.

Most often, the designation of chromium is absent in the marking, since this element is necessarily included in the source material, in which it accounts for about 4%. Among the elements that are missing from the marking, carbon should be highlighted. For example, if the drill is marked P7M6K6, then it can be understood that the manufacturer used high-speed steel as a material, which includes tungsten in an amount of 7%, molybdenum - 6%, cobalt - 6%.

If you pay attention to domestic products, then there is no such information. However, this applies primarily to products with a diameter of less than 2 mm.

Devices with a diameter of 2-3 mm contain information about the geometry and grade of steel. Additional data have drills that represent other standard sizes: they also indicate the trademark, and sometimes the accuracy class of the drilling product.

What does drill color mean?

• bright gold;
• black golden;
• Gray;
• black.

By the gold color, you can understand that the manufacturer used titanium nitride in the manufacture of the tool. Such an operation provides such a drill with increased strength characteristics. Working with such a device, less friction between surfaces will be provided.

A black golden hue indicates that the starting material contains tempering, the purpose of which is to relieve internal stress.

The gray color indicates that the drill in question has not been finished in order to increase the level of protection and strength of the material. From this we can conclude that this device has a low level of performance, and therefore it will fail pretty soon.

The black color allows us to say that during the manufacture of the drill, an operation was carried out, which consisted of exposing the product to superheated steam. The benefit of it is to increase its wear resistance.

Features of drilling stainless steels

It is possible to avoid this if:

• The problem with the heat sink will be solved, for which cooling is used;
• Work will be done with drills that handle heat best and have the best chip removal capability.

High speed steel HSSCo (M35) or similar marking is used as material for cobalt drilling products for metal. A feature of these drills is that during their manufacture, manufacturers have incorporated special properties into them, which allow them to effectively create holes in difficult-to-machine stainless steels.

Steel R6M5K5 contains 5% cobalt, due to which the drill acquires an increased red hardness. It is about the property of remaining as hard and resistant to wear as in the ordinary state, under conditions of heating to a temperature of red heat. A similar effect is achieved through heat treatment.

The manufacturing process involves the use of more expensive grinding technology. In other words, this device resembles a spiral, where a grinding machine is used to create grooves. This eliminates the appearance of internal tension on the device, while the surfaces remain smooth. This creates more favorable conditions for chip removal.

The upper part of the working device is located at an angle of 135 degrees and is characterized by the presence of a cruciform undercut. A similar angle is formed by the working edges of the fixture. It provides a reduction in the area of ​​the working area of ​​the product. As a result, it is exposed to less stress. As for the cruciform point undercut, its presence provides a decrease in the dead zone between the working edges.

Tool cost

On average, cobalt drills used in stainless steel work are 4-5 times more expensive than conventional drills. The cost of a drill belonging to the cobalt category is influenced by a number of parameters:

• construction (one- or two-sided);
• working diameter;
• length (total and working);
• the trade mark under which the drill is produced.

Cobalt drilling tools made by well-known and reputable European companies are distinguished by the maximum price on the domestic market. The budget option are drills of the domestic trade mark "Zubr", also produced in the "Cobalt" category. Despite the low cost, the domestic cobalt tool is of decent quality and allows you to create accurate and accurate holes in the material being processed.

Description

The main feature of cobalt drills is the high toughness of the alloy. Where a simple tool overheats quickly, a cobalt-doped product guarantees much more stable performance. It is quite difficult and difficult to organize everything competently. The cobalt drill works well with vertically oriented workpieces. It is practically a versatile tool suitable for a wide range of jobs.

The main structural material is high-speed steel. Due to the use of cobalt (up to 5%), forced heat removal can be avoided in most cases. Drill sharpening angles (at the top) 135 degrees. With their help, it is possible to drill even extremely smooth surfaces without pre-countersinking - the drill will not go sideways (as they say, it belongs to the self-centering type).

And also worth noting:

• obtaining particularly accurate holes in size;
• no risk of burrs and other deformations;
• zero probability that the tool in the working area will "bite";
• maximum resistance to wear;
• the passage of channels is almost twice as fast compared to a simple steel drill.

The design of cobalt drills can be categorized as one-sided or two-sided.

1. The first type implies the execution of the cutting part strictly from one side.
2. In the second version, in fact, a pair of instruments is placed in a single body.

Selection Tips

The classic twist drills with cobalt additives are rarely produced. But if there are such products, then the structural basis for them is HSS steel. A similar substance perfectly cuts through metal. As a result, it becomes possible to make durable and long-lasting gimbals. When using drills with a tapered (stepped) cutting surface, it is easier to punch a hole in a thin metal layer.

They will also help in correcting defects left by other cutting tools. The choice of a specific version of stepped drills is determined by the type of metal. For dense workpieces, a golden tool is optimal. In domestic conditions, it is rarely used.

Another thing is a core drill (it is also an annular cutter). Such a cutting device is shaped like a cylinder. One of the edges is cutting. The energy consumption when using such tools is many times less than in other cases. The reason is simple: the contact area is relatively small. A core drill will help you punch a large hole. But this advantage is not the only one: the quality of the edge processing is higher than when using spiral modifications.

Perforated flat drills have a changeable working edge. With their help, it turns out to punch holes that are flawless in size and smoothness. Many craftsmen use feather structures instead of spiral ones, while they are relatively inexpensive.

Most often, a cobalt drill belongs to the P6M5K5 type. The R9K15 brand is also popular - it contains 15% cobalt. Imported products of the same type are designated HSS-E. It is necessary to take into account the size range of structures. The main gradation is as follows:

• short type (length from 2 to 13.1 cm with a cross-section of 0.03-2 cm);
• elongated type (1.9-20.5 cm and 0.03-2 cm, respectively);
• fully long drills (5.6-25.4 cm and 0.1-2 cm).

When making drilling work, you need to focus on the depth of metal penetration. In many domestic situations, a thickness of 14 mm is sufficient. Other popular sizes - 6.7x109, 4x75x43, 5x86x52 mm

Additionally, when choosing a drill modification, you must pay attention to the range of leading suppliers, such as:

• Bosch;
• "Bison";
• rare stamps from the USSR (they are rare, but differ in their amazing parameters).

General terms of delivery and pickup:

- At the moment, pickup does not work!

- when paying on the spot, payment for products occurs before unloading the machine (deposit);

- in case of partial or complete refusal of high-quality and paid products at the time of delivery, the funds are returned to the buyer in proportion to the decrease in the cost of the order;

- when ordering goods by individual size or with cutting to individual size (linoleum, gypsum plasterboard, plywood, cable, rolled metal, etc.), 100% prepayment of the order is made, refusal from quality goods sold by the meter, as well as from goods manufactured by individual size is not possible;

- delivery is carried out daily from 9-00 to 18-00;

- the cost of delivery does not include unloading, lifting, as well as cutting and sawing of materials;

- unloading time is limited depending on the weight of the cargo;

- delivery is carried out to the place where the car can go without violating traffic rules and the risk of damage to the vehicle;

- self-pickup is carried out only after prior agreement with the manager of the online store;

- bulky material (insulation, barrels, etc.) is calculated based on the volume of the cargo;

- additional requirements for the car, for example, a low height for entering a parking lot or an open body for vertical unloading is paid additionally: + 25% to the cost of the standard tariff.

The cost of loading and unloading and lifting to the floor

Multichannel phone: +7 (495) 968-73-05

Delivery to regions of Russia:

- delivery to the regions of Russia is carried out by means of the transport company CDEK and PEK 2 times a week;

- the goods are shipped to the transport company only after 100% payment for the order;

- the services of the transport company are fully paid by the buyer upon receipt;

- delivery to TC SDEK and PEC 500 rubles.

- return of goods of proper quality through the shopping mall is carried out at the expense of the Buyer.

Opening hours:

Monday-Saturday: 8:00 am to 7:00 pm

Areas of use

Cobalt boring tools are excellent for both tough and hard alloys. It can be used on copper and metal with stainless properties. They also note the suitability of such devices for:

• acid resistant steel;
• heat-resistant metal;
• processing of casting molds made of steel;
• handling of corrosion-resistant connections;
• processing of alloyed alloys;
• the passage of cast iron;
• fast and accurate machining of holes on metal cutting equipment.

The wear resistance of cobalt drills allows for a long service life. You can not be afraid of negative consequences even with intensive long work and significant warming up. A specially thought-out design makes it possible to accurately and accurately drill large holes. Additional accessories are not required for such work. There is a groove that is ground for the fastest possible removal of chips.

It is also worth noting the presence of a reinforced shank. It minimizes the risk of breakage. As a result, the standard term of use increases. The cobalt additive guarantees excellent drilling in ductile metals. This includes primarily lead and aluminum, but tin and copper also fall into this category.

Benefits of cobalt drills

As noted earlier, the main advantages of these tools are high wear resistance and high temperature resistance. In other words, cobalt drills will last longer in the home, as they are less susceptible to mechanical damage and hold well at high melting temperatures.

In addition, the advantages and features of these drilling tools also include:

• Large sharpening angle (approx. 135 °), which is excellent for drilling round and smooth surfaces.
• Specific design that allows precise and accurate drilling of large holes without additional tools.
• Ground groove for fast chip evacuation.
• Reinforced shank, due to which the possibility of breakage is minimized, and, accordingly, the service life is increased.
• The presence of cobalt in the composition of the tool, which allows drilling of ductile metals such as aluminum, lead, copper or tin.

How to drill stainless steel with a cobalt drill

the following parameters are recommended:

Cutting speed. The optimal value is 10 m / min. The value given will be optimal for drilling in most stainless steels. In addition, its use will provide an opportunity to select rpm.

You can determine the turnover using the following formula:

n = 3180 / D, where

for drills with a diameter of 1.0 - 3180 rpm;

for drill 5.0 already 636 rpm;

Innings. To calculate this parameter, you should also use a simple formula:

0.005-0.01d mm / n,

where d is the drill diameter.

In simpler words, in one minute a metal drill with a diameter of 5 mm should create a hole 3 mm deep. When working with a metal drill with a diameter of 10 mm, the hole to be created should have a size of 1.6 mm.

The overheating problem is solved with oleic acid, which will act as a coolant.

Main characteristics

The most significant characteristics of cobalt and other materials difficult to process include the following.

1. Even when drilling perfectly smooth surfaces, cobalt tools do not drift to the side at the initial stage of processing, therefore, in the location of the center of the hole to be created, it is possible not to make indentations using a core or countersink.
2. Holes created with cobalt drills are distinguished not only by exceptional accuracy of geometric parameters, but also by high quality workmanship: there are no burrs or other defects on the inner surface of such holes. In addition, the use of this tool for drilling stainless steel avoids such a serious problem as biting the material in the processing area.
3. Cobalt alloyed HSS drills are highly wear resistant.
4. If we compare such drills with others, then the processing speed when using them is almost twice as much.
5. Due to the mechanical characteristics of the material of manufacture and the design features of such drills, they are successfully used for precise drilling of pipes and welds.
6. Drilling stainless steel or any other material with cobalt drills requires less physical effort than other types of tools.

Cobalt drills are produced by most manufacturers of accessories and consumables

Review overview

The “Practice Expert” model gives excellent results. Reviews indicate that this tool outperforms 95% of industrial mass production

Attention is also paid to bending strength and long service life. The drill of this version is installed exactly

He did not have any particular shortcomings.

A product called Bosch HSS-Co is also popular. Even the fact that, according to some sources, they are produced in China does not interfere. As for the comparison of the FIT and KEIL brands, everything is not so simple. FIT products are significantly cheaper. But KEIL has a more perfect sharpening. In terms of redness, these brands are on a par.

In the next video, you will find an overview of a set of cobalt drills 1-10mm from China.