Types of metal drills and their purpose, characteristics of spiral drills

Changed and forgot | 06/28/2015

A universal and important tool, without which no repair can be done, regardless of the complexity of the work performed, is a drill. Today, the building materials market offers a wide selection of different types of drills. All drills differ not only in length and diameter, but also in the material for which they are intended for drilling (wood, metal, concrete, ceramic tiles, brick, glass). Before drilling a particular material, it is necessary to select the appropriate drill size. Its type is selected depending on the work performed.

Types of metal drills and their purpose, characteristics of spiral drills

After reading this article, you will learn:

1. what types of metal drills exist;
2. where to find their markings;
3. what important characteristics do these instruments have;
4. what do they influence;
5. What kind of equipment are metal drills installed on?

Photo No. 1: metal drills

Let's start with the basics.

About cobalt drills. Their review, alloy and characteristics.

Good afternoon. In this article we will write about drills, what kind of metal drills there are, their purpose and areas of application, as well as the alloys from which they are made. I’ll tell you right away what niche our company occupies - we sell tools for various purposes, including we import drills from China.

Metal drills come with different types of shanks. The most common of them are: cylindrical shank (c\x) and conical shank (k\x). There are also drills with a triangular shank and a hex shank.

Drills come in several series:

• The average series with c\x is described in GOST 10902-77.
• A short series with c\x is described in GOST 4010-77.
• A long series with c\x is described in GOST 886-77.
• Particularly long series - they are also called Extra long with c\x are described in DIN 1869. - Chinese standard.

If you carefully study these GOSTs, you will notice that they are all united by a reference to GOST 2034 - Technical requirements for drills. In GOST 2034, at the end of paragraph 1.2, the following is written: “At the customer’s request, it is allowed to manufacture drills from alloy steel grade 9ХС according to GOST 5950.” Those. Formally, drills can be made from any alloy.

The most popular are drills made of R6M5 alloy. What is R6M5?

Alloy R6M5 is otherwise called M2 (European name), HSS6542 - Chinese name.

Chemical composition of alloy R6M5 “W: 5.50-6.75; Mo:4.50-5.50; Cr:3.80-4.40; V:1.75-2.20;"

We often hear not the most flattering reviews about Chinese drills... Why does this happen? and what manufacturers and sellers hide behind this.

I’ll tell you a little about the standards and alloys that you buy and use not rarely, but most often.

The first place in cost in China goes to the HSS4241 alloy. Drills made from this alloy are available in “Black finish - black, not polished”, and they can also be ground (a little more expensive). In addition to the alloy, you can order a Titanium Nitride (TiN) coating - it’s also not that expensive, but the drill gets a marketable appearance for pennies. Another trick is Marking. The Chinese immediately warn that these drills are very cheap and can only be used on wood. However, this does not prevent the Russian importer from ordering the coveted “P6M5” marking. What kind of alloy is this? , the chemical composition of this alloy is “W: 1.50-2.50; Mo:0.60-1.20; Cr:3.80-4.40; V:0.50-0.70;" - which is translated into Russian designation as “Р2М1”. This alloy is very popular on the Russian market.

The second most expensive alloy in China is HSS4341. These drills are made in the same way as HSS4241 - they differ in different chemicals. composition in this case we get “W: 3.50-4.50; Mo:2.50-3.50; Cr:3.80-4.40; V:1.20-1.80;” - which translates into the Russian designation as “R4M3” - in terms of durability, these drills are significantly better than 4241. In terms of cost, they differ significantly from 4241. The buyer believes that these are good Chinese ones.

Third place goes to the alloy HSS9341. These drills are made in the same way as HSS4241 and HSS4341 - they differ in chemical. composition in this case we get “W: 8.50-9.50; Mo:2.70-3.30; Cr:3.80-4.40; V:1.30-1.70;” - which is translated into Russian designation as “Р9М3” - in terms of durability, these drills are almost like R6М5 (HSS6542). And the cost is almost no different from the R6M5. They are in very little demand in the Chinese market.

Fourth place deservedly goes to the alloy HSS6542 - P6M5. The execution is no different from its predecessors. The chemical composition is as follows: “W: 5.50-6.75; Mo:4.50-5.50; Cr:3.80-4.40; V:1.75-2.20;". They are popular in China, but they are brought to Russia much less than HSS4241 and HSS4341. The cost of these drills is significantly higher. Bringing these drills to Russia and honestly labeling them as R6M5 will be problematic due to the established market and this alloy simply cannot compete on prices.

The fifth place is occupied by the alloy “M35” - R6M5K5 or HSSCo, it is also a drill for stainless steel, it is also called a “cobalt drill”. This alloy has a new element - cobalt. Cobalt increases the heat resistance of the drill and also improves its mechanical properties. The design is slightly different from its predecessors; the Chinese do not coat them with titanium nitride - this makes no sense. The sharpening angle is 135°. Chemical composition “W: 6.00-6.70; Mo:4.70-5.20; Cr:3.80-4.50; V:1.70-2.00; Co:4.50-5.50;" , judging by the chemical composition, you can see that tungsten and molybdenum have a lower content tolerance - this means that the Chinese approach the manufacture of these drills more responsibly and with high quality than other alloys.

The sixth and last place is occupied by the M42 alloy. - R2M10K8. Drills made from this alloy are almost not represented on the Russian market, however, you can notice that Bimetallic Crowns are made from this alloy. Chemical composition “W: 1.15-1.85; Mo:9.00-10.00; Cr:3.50-4.25; V:0.95-1.35; Co:7.75-8.75;".

Chem summary compositions are given in the table

You can buy drills from us: Check out the availability and prices of drills by sending a request to our email address or call our phone number

A reputable supplier of drills should always have a chemical analysis of the drills. It is our custom to do a chemical analysis for each incoming batch and attach the results at the first request of the client.

There are many manufacturers of drills on the market. VIZ, Tulamash, TIZ and many others. We cannot say what alloy they use in the manufacture of drills, since we did not carry out chemical testing. analysis drilled them. In the near future we will compare drills from different manufacturers and post a video.

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Marking of drills for metal (Russian and foreign)

According to Russian GOST, all metal drills with a diameter of two millimeters or more are subject to marking. The designations contain information about the tool diameter and steel grade. Some models bear manufacturer's marks. To find out the markings of the drill, look at the shank of the tool.

Russian labeling looks like this.

Image No. 4: rules for deciphering Russian markings

Foreign metal drills made of high-speed steel are marked HSS. Depending on the modifications and manufacturing features, various additional designations are added to it.

Types of sharpening drills for metal

At the end of the article, we will talk about the types of sharpening of metal drills, which are used to restore dull tools and change their geometry.

Image No. 6: types of sharpening twist drills

1. Normal (single) sharpening (N). Considered universal. During normal sharpening, two cutting edges and one transverse edge are formed on the surface of the drill. The angle between the cutting edges is 118–120°. This type of sharpening can be used for drills with diameters up to 12 mm. Other technologies are suitable for tools with diameters up to 80 mm.
2. Single sharpening with sharpening of the cutting edge (NP). Reduces its length. Due to this, the load on the working part when performing drilling work is reduced.
3. Single sharpening with sharpening of the transverse edge and ribbon (NPL). Additionally reduces its width in the area of ​​the cutting part. The friction force is significantly reduced. In addition, an additional rear angle is formed. This results in easier cutting.
4. Double sharpening with sharpening of the transverse edge (DP). With double sharpening, 4 cutting edges and one transverse are formed. They look like broken lines. The durability of drills with double sharpening increases by 5–7 times when processing cast iron workpieces and by 2.5–3 times when drilling steel.
5. Double sharpening with sharpening of the transverse edge and ribbon (DPL). With this sharpening, drilling is further facilitated.

Straight Shank Drill

Home \ Drilling tools \ Drill with a cylindrical shank
Spiral drills with a cylindrical shank are used to create holes in various materials using mechanized hand tools, or less often, using stationary machines. Chucks are used to fasten such drills. GOST provides for the production of central drills with a diameter of up to 20 mm.

Twist drill from the main series GOST 10902

Twist drill with long series GOST 886

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