Drilling wood is one of the most common tasks in repair and construction, but it is not always possible to purchase a high-quality wood drill. Therefore, it is very important to know how to choose a good tool and be able to sharpen a blunt product!

Modern drills are often sold with a set of different drills, however, basically, they are always the same type of product, just different lengths and diameter. So you have to independently select the types of wood drills that meet all your tasks. Of course, such a set should include a twist drill for wood, products are presented in a wide range - from 3 to 52 mm in diameter! Good tool this kind should have a sharp point, thanks to which it does not slip off the surface.

Products with a diameter of 10 mm or more must have a hex shank so that they do not rotate during operation. It is also important to know how many revolutions during drilling should correspond to one or another tool diameter. For example, if you are dealing with small products up to 14 mm, you should set no more than 1700-1800 rpm for soft wood and half as much for drilling hard wood. Working with tools with a diameter of 16 to 25 mm, on hard rocks, you should adhere to 500 revolutions, you can increase the speed three times when drilling soft rocks.

The larger the diameter, the lower the speed - observing this ratio, you will prolong the life of the product for a long time! When choosing tools, pay attention to the color of the metal - if it's normal grey colour, then such a product has not undergone any additional processing, respectively, and it will not last long. Black color indicates treatment with very hot steam, and yellow inherent in products that are treated with titanium nitride, which increases the service life at times.

Long wood drills are very dependent on their diameter. You will not find thin and at the same time long products - why thinner tool, the shorter, otherwise it may break even if pressed lightly. So, a ten-millimeter drill can be up to 45 cm long, while a twelve-millimeter drill can be up to 60! Of course, it is not at all necessary to buy such long ones, unless you are dealing with drilling holes in thick beams.

Of course, you must also observe a sound ratio between the capabilities of the drill itself and the dimensions of the drill, because a product 45 cm long and 52 mm in diameter will weigh almost 3 kilograms! An ordinary household drill can hardly crank it even when idle! Experienced builders even low-speed drill-mixers are used when working with such "giants"!

However, there is also a trade-off between the ability to drill holes. large diameter and the weight of the drill! Products of this type are called feathers, since drilling occurs due to the "feather" of the desired diameter at the end of a long rod. On the market you will find tools from 10 to 55 mm. True, this compromise option also has significant disadvantages, compared to the same spiral ones - they do not have a chip outlet, which greatly complicates the process of working with deep holes. Most often, these are used for drilling not very thick boards, as well as fiberboard and chipboard, so they are produced up to 15-20 cm long. True, there are also extension cords with which you can make holes up to 40 cm deep!

Typically, these tools have a hex shank to help fit the chuck. This option is perfect for holes for door locks. On the other hand, you can work with them even with not very powerful tools, and at a price they are much cheaper than spiral ones - sometimes the difference is 5-10 times! Recommended revolutions when drilling for hard wood with tools up to 25 mm - 1500 rpm, if drills with a larger diameter - reduce to 1000. Soft rocks can be drilled at 1500-2000 revolutions.

Forstner's drills are especially popular among furniture makers, as they can be used to drill a blind hole with a flat, even and smooth bottom. That is why such drills are often called cork drills, although in fact such a definition does not quite suit them, because there are special products of a different design just for drilling plugs.

The diameter of the products is presented in the range from 10 to 50 mm. Quite often, the cutting edges are made of hard alloys, which significantly increases the service life of the product. As a rule, such drills are up to 10 cm in length, although this parameter can be tripled with the help of extension cords. In practice, the recommended revolutions for soft woods range from 2500 rpm to 1000 rpm for large diameters, while it is recommended to drill hard woods at fairly low speeds. For example, for tools with a diameter of 15 mm, it is recommended to set no more than 500 rpm.

The external resemblance to the crown was the reason for the emergence of another name for such products - crowns. Their most important advantage lies in the ability to make holes of large diameters, which cannot be done even with the largest twist or feather drills. The crowns look like a ring with teeth, usually sold in sets, as bits on one base, inside which there is a center drill. Of course, such holes cannot be made too deep - ordinary models can handle material up to 22 mm, professional ones - up to 64 mm. In addition, such tools are effective when working with plastics and drywall.

It does not hurt to note another unusual type - termite drills, or, as they are called in professional language, milling drills. Thanks to the characteristic outward appearance such products cannot be confused with anything - they have a monolithic tip, like a conventional twist drill, and a core with many cutting edges. With the help of such tools, not only drilling is performed, but also milling - first we drilled, and then we go to the right side... You can work with milling products both on wood and on plastic. Their diameter does not exceed 12 mm.

". Today I want to talk about how easy it is to make feather drills in wood.

The other day I needed to drill in Chipboard holes large diameter, namely 40 and 20 mm. And then it turned out that I did not have the necessary drills !!!

No ... Of course I have a lot of different nib drills. And ordinary and several wedges. But, here, the trouble is that I was working at home in the basement, and my drills are located on the other side of the city, namely, at a construction site, where I last used them ...

And so I decided to quickly make the necessary drills from what was at hand ...

And, in fact, I needed the following for this:

1. a piece of sheet "stainless steel", 2 mm thick. (Not necessarily "stainless steel" ... It's just that I had it lying around ..)
2. A metal pin with a diameter of 10 mm. (You can also be thinner ... It's just, I had this one))))
3. Bolt (screw) M6 (or thinner).

(Before starting the story, I want to apologize for the poor quality of the photo. The fact is that I had no time to photograph the process step by step, so I just turned on the video recording on my smartphone, and then took screenshots from it ...)

So where did I start ... I found a piece sheet metal, 2 mm thick. I came across such a piece of "stainless steel"

I started with a drill with a diameter of 40mm. To begin with, I drew a drill blank on a piece of stainless steel:

Using a grinder with a cut-off wheel, I cut out a workpiece:

After that I made the drill shaft myself. I decided to make it from a ten-millimeter bar that was lying in my "scrap metal":

There was no thinner bar at hand ... But I thought that this one would do too. After all, a rod of this diameter will fit into any cartridge household drill... Of course, its thickness regulates the minimum diameter of the drill, but I always have drills up to twelve millimeters in stock ... (These are drills for metal, but they can be easily applied to wood as well). And feathers are needed only with large diameters ..

I cut a piece of the desired length from the rod:

Holding it in a vice, I cut a diametrical slot with a cutting wheel. I figured out the depth of the cut by eye, simply by attaching the workpiece and noting such a depth "so that it was normal" ...))))

After that I checked to see if my "nib" was inserted into the slot of the rod:

Aligning exactly in the center, I made a marker on the plane corresponding to the thickness of the rod:

Then I made cuts along these lines:

After changing the cut-off wheel to the cut-off wheel, I selected the metal between the slots.

Now we need to secure the feather to the rod. It is easier, of course, just to "drip" by welding. But, in order not to make the second rod (after all, I needed, in addition to the forty-millimeter one, also the twenty-millimeter one), I decided to fasten it with a screw. To do this, I drilled a hole in the rod, perpendicular to the slot. I used a drill with a diameter of 5 mm.

Then I drilled out the upper half of the rod (up to the slot) with a drill with a diameter of six millimeters:

And in the lower half I cut the M6 ​​thread:

After that, I inserted the pen into the shaft, aligned it, and, marking the center with a drill, I took it out and drilled a hole with a diameter of 6 mm.

Now you can insert the nib into the shaft and fasten it with a screw:

The M6 ​​bolt was my screw. It was easier for me to cut the threads. But if you do not have taps at hand, you can use it as a bolt - screw the nut on the other side. It will not interfere, it will simply not be so convenient to fasten - you will need two keys ...

Now let's sharpen our drill. I used a homemade emery emery with a diamond cup ... Just because I had it close at hand:

And you can sharpen it with anything, even with a grinder ... You don't need to observe a certain angle here. It should not be made too sharp simply:

Everything! The drill is ready. It will drill both wood and chipboard quite easily:

Because the rod was already ready, it was not difficult to make a second feather, 20 millimeters wide:

Of course, these drills are not suitable for permanent, professional work... For this you need purchased drills made of good steel ... But I am not a professional !!! I'm a DIY! And the last time before this case, I used a feather drill of this diameter about ten years ago !!! And again it was needed !!)))).

It took me about twenty minutes to make it. (During this time, I did not go, I would even go to the store for him))). And the production of subsequent diameters is half that ...

And I did the job for them - I drilled the hole I needed. After that I will put it on the shelf, and next time I will need it ... maybe in a year ... Or maybe in five !!! ... (Or maybe it won't be needed at all!)))) But it will no longer need to be bought or made ...)))

By the way, at a construction site, when I needed to fasten beams and rafters, I also used just such a drill. At that time, I lent my friend my long drill for wood, and, as usually happens, he did not return it to me on time ... And in order not to waste days, I lost minutes - I made the same drill, only half a meter long, and did the job ...

For such purposes, these drills are very well suited !!!

Work on drilling holes in metal, depending on the type of holes and the properties of the metal, can be performed different tools and using various techniques. We would like to tell you about the methods of drilling, tools, as well as safety measures when performing these works.

Drilling holes in metal may be needed for repairs engineering systems, household appliances, a car, the creation of structures from sheet and profile steel, the design of crafts from aluminum and copper, in the manufacture of boards for radio equipment and in many other cases. It is important to understand what tool is needed for each type of work, so that the holes are of the right diameter and in a strictly designated place, and what safety measures will help to avoid injuries.

Tools, fixtures, drills

The main tools for drilling are hand and power drills, as well as, if possible, drilling machines... The working body of these mechanisms - a drill - can have a different shape.

There are drills:

• spiral (most common);
• screw;
• crowns;
• conical;
• feathers, etc.

Drill production of various designs standardized by numerous GOSTs. Drills up to Ø 2 mm are not marked, up to Ø 3 mm - the shank indicates the section and steel grade, larger diameters may contain Additional information... To obtain a hole of a certain diameter, you need to take a drill a few tenths of a millimeter smaller. The better the drill is sharpened, the smaller the difference between these diameters.

Drills differ not only in diameter, but also in length - they are produced short, elongated and long. Important information is the ultimate hardness of the metal being processed. The drill shank can be cylindrical or tapered, which should be borne in mind when choosing a drill chuck or adapter sleeve.

1. Drill with cylindrical shank. 2. Drill with taper shank. 3. Drill with a sword for carving. 4. Center drill. 5. Drill with two diameters. 6. Center drill. 7. Conical drill. 8. Conical multistage drill

Some work and materials require special sharpening. The harder the metal being processed, the sharper the edge must be. For thin sheet metal, a conventional twist drill may not work; you will need a tool with a special sharpening. Detailed recommendations for of various types drills and processed metals (thickness, hardness, hole type) are quite extensive, and we will not consider them in this article.

Various types of drill sharpening. 1. For rigid steel. 2. For of stainless steel... 3. For copper and copper alloys. 4. For aluminum and aluminum alloys. 5. For cast iron. 6. Bakelite

1. Standard sharpening. 2. Free sharpening. 3. Diluted sharpening. 4. Heavy sharpening. 5. Separate sharpening

To fix the parts before drilling, use a vice, stops, conductors, corners, clamps with bolts and other devices. This is not only a safety requirement, but in fact it is more convenient, and the holes are of better quality.

For chamfering and processing the surface of the channel, a cylindrical or conical countersink is used, and a hammer and a center punch are used to mark a point for drilling and so that the drill “does not jump off”.

Advice! The best drills are still considered issued in the USSR - the exact adherence to GOST on the geometry and composition of the metal. The German Ruko with titanium coating are also good, as well as drills from Bosch - a proven quality. Good feedback about Haisser products - powerful, as a rule, large diameter. The Zubr drills, especially the Cobalt series, have shown themselves worthy.

Drilling modes

It is very important to correctly position and guide the drill and select the cutting mode.

When making holes in metal by drilling important factors are the number of revolutions of the drill and the feed force applied to the drill, directed along its axis, providing the drill depth at one revolution (mm / rev). When working with different metals and drills, different cutting conditions are recommended, and the harder the metal being processed and the larger the drill diameter, the lower the recommended cutting speed. The indicator of the correct mode is beautiful, long chips.

Use the tables to choose the right mode and not dull the drill prematurely.

Feed S 0, mm / rev	Drill diameter D, mm
	2,5	4	6	8	10	12	146	20	25	32
	Cutting speed v, m / min
When drilling steel
0,06	17	22	26	30	33	42	—	—	—	—
0,10	—	17	20	23	26	28	32	38	40	44
0,15	—	—	18	20	22	24	27	30	33	35
0,20	—	—	15	17	18	20	23	25	27	30
0,30	—	—	—	14	16	17	19	21	23	25
0,40	—	—	—	—	—	14	16	18	19	21
0,60	—	—	—	—	—	—	—	14	15	11
When drilling cast iron
0,06	18	22	25	27	29	30	32	33	34	35
0,10	—	18	20	22	23	24	26	27	28	30
0,15	—	15	17	18	19	20	22	23	25	26
0,20	—	—	15	16	17	18	19	20	21	22
0,30	—	—	13	14	15	16	17	18	19	19
0,40	—	—	—	—	14	14	15	16	16	17
0,60	—	—	—	—	—	—	13	14	15	15
0,80	—	—	—	—	—	—	—	—	—	13
When drilling aluminum alloys
0,06	75	—	—	—	—	—	—	—	—	—
0,10	53	70	81	92	100	—	—	—	—	—
0,15	39	53	62	69	75	81	90	—	—	—
0,20	—	43	50	56	62	67	74	82	-	-
0,30	—	—	42	48	52	56	62	68	75	—
0,40	—	—	—	40	45	48	53	59	64	69
0,60	—	—	—	—	37	39	44	48	52	56
0,80	—	—	—	—	—	—	38	42	46	54
1,00	—	—	—	—	—	—	—	—	—	42

Table 2. Correction factors

Table 3. RPM and feed for different drill diameters and drilling in carbon steel

Types of holes in metal and how to drill them

Hole types:

• deaf;
• end-to-end;
• half (incomplete);
• deep;
• large diameter;
• for an internal thread.

Thread holes require the determination of diameters with tolerances established in GOST 16093-2004. For common hardware, the calculation is shown in table 5.

Table 5. Ratio of metric and inch threads, as well as selection of hole size for pre-drilling

Metric thread				Inch thread				Pipe thread
Thread diameter	Thread pitch, mm	Thread hole diameter		Thread diameter	Thread pitch, mm	Thread hole diameter		Thread diameter	Thread hole diameter
		min.	Max.			min.	Max.
M1	0,25	0,75	0,8	3/16	1,058	3,6	3,7	1/8	8,8
M1.4	0,3	1,1	1,15	1/4	1,270	5,0	5,1	1/4	11,7
M1.7	0,35	1,3	1,4	5/16	1,411	6,4	6,5	3/8	15,2
M2	0,4	1,5	1,6	3/8	1,588	7,7	7,9	1/2	18,6
M2.6	0,4	2,1	2,2	7/16	1,814	9,1	9,25	3/4	24,3
M3	0,5	2,4	2,5	1/2	2,117	10,25	10,5	1	30,5
M3.5	0,6	2,8	2,9	9/16	2,117	11,75	12,0	—	—
М4	0,7	3,2	3,4	5/8	2,309	13,25	13,5	11/4	39,2
M5	0,8	4,1	4,2	3/4	2,540	16,25	16,5	13/8	41,6
M6	1,0	4,8	5,0	7/8	2,822	19,00	19,25	11/2	45,1
М8	1,25	6,5	6,7	1	3,175	21,75	22,0	—	—
M10	1,5	8,2	8,4	11/8	3,629	24,5	24,75	—	—
M12	1,75	9,9	10,0	11/4	3,629	27,5	27,75	—	—
M14	2,0	11,5	11,75	13/8	4,233	30,5	30,5	—	—
М16	2,0	13,5	13,75	—	—	—	—	—	—
M18	2,5	15,0	15,25	11/2	4,333	33,0	33,5	—	—
M20	2,5	17,0	17,25	15/8	6,080	35,0	35,5	—	—
M22	2,6	19,0	19,25	13/4	5,080	33,5	39,0	—	—
M24	3,0	20,5	20,75	17/8	5,644	41,0	41,5	—	—

Through holes

Through holes penetrate the workpiece completely, forming a passage in it. A feature of the process is the protection of the surface of the workbench or table top from the drill going out of the workpiece, which can damage the drill itself, as well as provide the workpiece with a "burr" - a guard. To avoid this, use the following methods:

• use a workbench with a hole;
• put a gasket made of wood or "sandwich" - wood + metal + wood under the part;
• put a metal bar with a hole for the free passage of the drill under the part;
• reduce the feed rate in the last step.

The latter method is mandatory when drilling holes "in place" so as not to damage closely spaced surfaces or parts.

Holes in thin sheet metal are cut with nib drills because the twist drill will damage the edges of the workpiece.

Blind holes

Such holes are made to a certain depth and do not penetrate the workpiece through and through. There are two ways to measure depth:

• limiting the length of the drill with a sleeve stop;
• limiting the length of the drill with a chuck with an adjustable stop;
• using a ruler fixed on the machine;
• a combination of ways.

Some machines are equipped with an automatic feed to a predetermined depth, after which the mechanism stops. During the drilling process, it may be necessary to stop several times to remove the chips.

Complex holes

Holes located on the edge of the workpiece (half) can be made by connecting two workpieces or the workpiece and the gasket with the edges and clamping them in a vice and drilling a full hole. The gasket must be made of the same material as the workpiece to be machined, otherwise the drill will "go" towards the least resistance.

A through hole in the corner (shaped metal rolling) is performed by fixing the workpiece in a vice and using wood gasket.

It is more difficult to drill a cylindrical workpiece tangentially. The process is split into two steps: preparation perpendicular to the hole platforms (milling, countersinking) and drilling itself. Drilling holes in angled surfaces also begins with site preparation, after which a wooden spacer is inserted between the planes, forming a triangle, and a hole is drilled through the corner.

The hollow parts are drilled by filling the cavity with a wood cork.

Shoulder holes are produced using two techniques:

1. Reaming. The hole is drilled to the full depth with a drill of the smallest diameter, after which it is reamed to a given depth with drills with diameters from smaller to larger. The advantage of the method is a well-centered hole.
2. Reducing the diameter. A hole of the maximum diameter is drilled to a given depth, then the drills are changed with a sequential decrease in the diameter and deepening of the hole. This method makes it easier to control the depth of each step.

1. Reaming the hole. 2. Reducing the diameter

Large holes, circular drilling

Obtaining large-diameter holes in massive workpieces, up to 5-6 mm thick, is a laborious and costly business. Relatively small diameters - up to 30 mm (maximum 40 mm) can be obtained using tapered, or better step-taper drills. For holes with a larger diameter (up to 100 mm), you will need hollow bimetallic or carbide-tipped bits with a center drill. Moreover, craftsmen traditionally recommend Bosch in this case, especially on hard metal, for example, steel.

This hole drilling is less energy intensive, but can be more costly. In addition to drills, the power of the drill and the ability to work at the lowest speeds are important. Moreover, the thicker the metal, the more you will want to make a hole on the machine, and if a large number holes in a sheet with a thickness of more than 12 mm, it is better to immediately look for such an opportunity.

In a thin-sheet blank, a large-diameter hole is obtained with the help of narrow-toothed crowns or a milling cutter fixed on a "grinder", but the edges in the latter case leave much to be desired.

Deep holes, coolant

Sometimes a deep hole is required. In theory, this is such a hole, the length of which is five times larger diameter... In practice, deep drilling is called drilling, requiring periodic forced removal of chips and the use of coolants (cutting fluids).

In drilling, coolant is needed primarily to reduce the temperature of the drill and workpiece, which are heated by friction. Therefore, when making holes in copper, which has a high thermal conductivity and is itself capable of removing heat, the coolant can be omitted. Cast iron can be drilled relatively easily and without lubrication (except for high-strength ones).

In production, industrial oils, synthetic emulsions, emulsols and some hydrocarbons are used as coolant. In home workshops, you can use:

• technical vaseline, castor oil - for mild steels;
• laundry soap- for aluminum alloys such as D16T;
• a mixture of kerosene with castor oil - for duralumin;
• soapy water - for aluminum;
• turpentine diluted with alcohol - for silumin.

The universal refrigerated liquid can be prepared independently. To do this, you need to dissolve 200 g of soap in a bucket of water, add 5 tablespoons of engine oil, you can waste it, and boil the solution until a soapy homogeneous emulsion is obtained. Some craftsmen use lard to reduce friction.

Processed material	Coolant lubricant
Steel:
carbonaceous	Emulsion. Sulfurized oil
structural	Sulfurized kerosene oil
instrumental	Mixed oils
alloyed	Mixed oils
Malleable cast iron	3-5% emulsion
Iron casting	No refrigeration. 3-5% emulsion. Kerosene
Bronze	No refrigeration. Mixed oils
Zinc	Emulsion
Brass	No refrigeration. 3-5% emulsion
Copper	Emulsion. Mixed oils
Nickel	Emulsion
Aluminum and its alloys	No refrigeration. Emulsion. Mixed oils. Kerosene
Stainless, heat-resistant alloys	A mixture of 50% sulfurized oil, 30% kerosene, 20% oleic acid (or 80% sulfofresol and 20% oleic acid)
Fiber, vinyl plastic, plexiglass and so on	3-5% emulsion
Textolite, getinax	Compressed air blowing

Deep holes can be made with solid and circular drilling, and in the latter case, the central rod formed by the rotation of the crown is not broken out entirely, but in parts, weakening it with additional small-diameter holes.

Solid drilling is performed in a well-fixed workpiece with a twist drill, into the channels of which coolant is supplied. Periodically, without stopping the rotation of the drill, you need to remove it and clean the cavity from chips. Work with a twist drill is performed in stages: first, take a short one and drill a hole, which is then buried with a drill of the appropriate size. If the hole depth is significant, it is advisable to use jig bushings.

If you regularly drill deep holes, we recommend purchasing a special machine with automatic coolant supply to the drill and accurate centering.

Drilling by marking, template and jig

You can drill holes according to the made markings or without them - using a template or a jig.

Marking is done with a center punch. A blow of a hammer marks the place for the tip of the drill. You can also mark the place with a felt-tip pen, but the hole is also needed so that the tip does not move from the intended point. The work is carried out in two stages: preliminary drilling, hole inspection, final drilling. If the drill has "gone" from the intended center, notches (grooves) are made with a narrow chisel, guiding the point to the specified place.

To determine the center of a cylindrical blank, a square piece of sheet metal is used, bent at 90 ° so that the height of one shoulder is approximately one radius. Applying a corner on different sides of the workpiece, draw a pencil along the edge. As a result, you have an area around the center. You can find the center by the theorem - the intersection of perpendiculars from two chords.

The template is needed when making a series of similar parts with several holes. It is convenient to use it for a pack of thin-sheet blanks connected by a clamp. In this way, several drilled workpieces can be obtained at the same time. Instead of a template, a drawing or diagram is sometimes used, for example, in the manufacture of parts for radio equipment.

The conductor is used when it is very important to keep the distance between the holes and the strict perpendicularity of the channel. When drilling deep holes or when working with thin-walled tubes, in addition to the conductor, guides can be used to fix the position of the drill relative to the metal surface.

When working with a power tool, it is important to remember about human safety and prevent premature wear of the tool and possible marriage. In this regard, we have collected some useful tips:

1. Before work, you need to check the fastenings of all elements.
2. When working on a machine or with an electric drill, clothes should not contain elements that can get under the influence of rotating parts. Protect eyes from shavings with goggles.
3. The drill, when approaching the metal surface, should already rotate, otherwise it will quickly become dull.
4. It is necessary to remove the drill from the hole without turning off the drill, reducing the speed if possible.
5. If the drill does not go deep into the metal, then its hardness is lower than that of the workpiece. Increased hardness in steel can be detected by drawing a file over the sample - the absence of traces indicates increased hardness. In this case, the drill must be selected from a carbide alloy with additives and work at low speeds with a small feed.
6. If the small diameter drill does not fit well in the chuck, wind a few turns of brass wire around the shank, increasing the grip diameter.
7. If the surface of the workpiece is polished, place a felt washer over the drill to ensure it does not scratch even when touching the drill chuck. When securing polished or chromed steel workpieces, use cloth or leather spacers.
8. When making deep holes, a rectangular piece of foam, planted on a drill, can serve as a gauge and, at the same time, rotate to blow off small chips.

Long metal drills are used to drill through and blind holes in spindles, shafts and long parts. They are characterized by low productivity. The ground long drill for metal has high fracture resistance and is used when working with alloyed and unalloyed carbon steel, Petrometal non-ferrous metals, gray and ductile iron, cermets, bronze and brass. Manufactured in accordance with GOST 886-77, GOST 886-77, GOST 2092-77 and GOST 22094-76. The GOSTs provide information on the main dimensions of the devices. They have a diameter of 1 to 20 mm, and a total length of 56 to 254 mm. In them, unlike other cutting tools, the total and working distance is increased, as well as the angle at the top of the cutting edges. In all standard designs it is 118 degrees, and in long devices it is 135. This feature allows you to work with materials that are much heavier, since the load on the tool is reduced. This leads to an increase in the service life of the device, as well as an increase in the intervals between sharpening.

How to choose an extended metal drill?

When choosing an extended cutterbar, first of all pay attention to the following details:

• Extra long twist drills;
• With cylindrical shank.

Basic dimensions

Name	Diameter, mm	Length, mm
	1,5	70
Drill bit for metal extended DIN 340	2	85
Drill bit for metal extended DIN 340	2	85
Drill bit for metal extended DIN 340	2,9	95
Drill bit for metal extended DIN 340	3	100
Drill bit for metal extended DIN 340	3	100
Drill bit for metal extended DIN 340	3,2	300
Drill bit for metal extended DIN 340	3,2	106
Drill bit for metal extended DIN 340	3,3	106
Drill bit for metal extended DIN 340	3,5	106
Drill bit for metal extended DIN 340	3,5	112
Drill bit for metal extended DIN 340	3,8	112
Drill bit for metal extended DIN 340	4	119
Drill bit for metal extended DIN 340	4	119
Drill bit for metal extended DIN 340	4	119
Drill bit for metal extended DIN 340	4,1	300
Drill bit for metal extended DIN 340	4,2	119
Drill bit for metal extended DIN 340	4,5	119
Drill bit for metal extended DIN 340	4,5	126
Drill bit for metal extended DIN 340	5	126
Drill bit for metal extended DIN 340	5	132
Drill bit for metal extended DIN 340	5	132
Drill bit for metal extended DIN 340	5,5	300
Drill bit for metal extended DIN 340	5,5	139
Drill bit for metal extended DIN 340	6	139
Drill bit for metal extended DIN 340	6	139
Drill bit for metal extended DIN 340	6	139
Drill bit for metal extended DIN 340	6,5	300
Drill bit for metal extended DIN 340	7	148
Drill bit for metal extended DIN 340	7	156
Drill bit for metal extended DIN 340	7,5	156
Drill bit for metal extended DIN 340	8	156
Drill bit for metal extended DIN 340	8	165
Drill bit for metal extended DIN 340	8	165
Drill bit for metal extended DIN 340	8,5	300
Drill bit for metal extended DIN 340	9	165
Drill bit for metal extended DIN 340	9	175
Drill bit for metal extended DIN 340	10	175
Drill bit for metal extended DIN 340	10	184
Drill bit for metal extended DIN 340	10	300
Drill bit for metal extended DIN 340	11	195
Drill bit for metal extended DIN 340	12	205
Drill bit for metal extended DIN 340	12	300

Manufacturers

The extended spiral drill is produced in three countries:

1. Russia;
2. Germany;
3. China

The most best devices manufactured in Germany by Heller, they have the greatest strength and durability.

How to choose a drill for metal: Video

1. Sharpening angle of the cutting part. For this device, it should be 135 degrees.
2. Marking. From it it will be clear what material the device is made of, and how it can be used.
3. Colour. Choose deep gold cutting tools as they have the strongest toughness and also have the lowest friction.
4. Manufacturing material. It affects the ability of the device to drill certain structures.

We also recommend that you pay attention to the model of your machine, its condition, power, the method of obtaining the workpiece (it can be casting, stamping, cutting), the accuracy of the hole obtained. Be sure to find out what tolerance and roughness the extra-long drill has. Also consider the depth of the hole to be machined.

Types and technical characteristics

The following cutting tools can have an elongated design:

• Extra long twist drills;
• Elongated spiral taper shank drills;
• With cylindrical shank.

Long series drills with a tapered shank have a special part of the tool that is clamped in the chuck of a drill or machine.

The length of the device is selected depending on the diameter of the hole, the size of the elongated drill for metal is not much larger than the standard sizes.

There are also extra-long metal drills, they are used to drill deep holes in steels that have a hardness of 1300 N / mm 2.

Basic dimensions

In the table below you can see the basic parameters of cutting tools with large size, namely with their diameter and length. For example, a 5 5 long drill has a length of 139 mm.

photo: dimensions of elongated drills for metal

Name	Diameter, mm	Length, mm
Drill bit for metal extended DIN 340	1,5	70
Drill bit for metal extended DIN 340	2	85
Drill bit for metal extended DIN 340	2	85
Drill bit for metal extended DIN 340	2,9	95
Drill bit for metal extended DIN 340	3	100
Drill bit for metal extended DIN 340	3	100
Drill bit for metal extended DIN 340	3,2	300
Drill bit for metal extended DIN 340	3,2	106
Drill bit for metal extended DIN 340	3,3	106
Drill bit for metal extended DIN 340	3,5	106
Drill bit for metal extended DIN 340	3,5	112
Drill bit for metal extended DIN 340	3,8	112
Drill bit for metal extended DIN 340	4	119
Drill bit for metal extended DIN 340	4	119
Drill bit for metal extended DIN 340	4	119
Drill bit for metal extended DIN 340	4,1	300
Drill bit for metal extended DIN 340	4,2	119
Drill bit for metal extended DIN 340	4,5	119
Drill bit for metal extended DIN 340	4,5	126
Drill bit for metal extended DIN 340	5	126
Drill bit for metal extended DIN 340	5	132
Drill bit for metal extended DIN 340	5	132
Drill bit for metal extended DIN 340	5,5	300
Drill bit for metal extended DIN 340	5,5	139
Drill bit for metal extended DIN 340	6	139
Drill bit for metal extended DIN 340	6	139
Drill bit for metal extended DIN 340	6	139
Drill bit for metal extended DIN 340	6,5	300
Drill bit for metal extended DIN 340	7	148
Drill bit for metal extended DIN 340	7	156
Drill bit for metal extended DIN 340	7,5	156
Drill bit for metal extended DIN 340	8	156
Drill bit for metal extended DIN 340	8	165
Drill bit for metal extended DIN 340	8	165
Drill bit for metal extended DIN 340	8,5	300
Drill bit for metal extended DIN 340	9	165
Drill bit for metal extended DIN 340	9	175
Drill bit for metal extended DIN 340	10	175
Drill bit for metal extended DIN 340	10	184
Drill bit for metal extended DIN 340	10	300
Drill bit for metal extended DIN 340	11	195
Drill bit for metal extended DIN 340	12	205
Drill bit for metal extended DIN 340	12	300

Drilling for the deaf, and through holes in parts of long length necessitates the need for long drills for metal. Sometimes there is no way to purchase cutting tool the desired length, which entails the need to lengthen the existing one. How to lengthen a drill bit for metal and is it effective?

Tool lengthening methods, their features

Most of the ways to extend the length of a product are by attaching an extension to the shank. The choice of a specific method should be based on the diameter of the tool, the presence auxiliary equipment, as well as the desired final length.

The most common ways are:

When lengthening the tool, it should be remembered that the part used as an extension should be selected with a slightly smaller diameter than the drill. In addition, when working with the converted product, it is necessary to correct the cutting conditions when drilling.

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Our own brand core drills are reliable and productive and can be used with turning, milling and drilling equipment. Qualified consultants will help you when choosing products and placing an order, comment on the characteristics and advantages of the products offered. A long warranty will ensure the prompt replacement or repair of equipment and tools, and constant promotions will be a pleasant bonus when buying.