14. Key making machines A decoder machine makes it possible to make keys for a lock when there is no original key to copy. This is possible because lock manufacturers often stamp the key code on locks and keys, and the locksmith immediately

2.14. Grinding and grinding machines Grinding is the processing of parts and tools using rotating abrasive or diamond grinding wheels, based on cutting the grains of a circle from the surface of a very thin layer of material in the form of the smallest

Chapter 6 WOODWORKING MACHINES 1. General information Woodworking equipment is divided into machines general purpose, machines for special productions and universal. General-purpose machines include machines for cutting boards, bars, shields, plates;

2. Circular saws Circular saws are used for cutting lumber, blanks, board materials (plywood, fibreboard, chipboard). Depending on the operations performed, the machines are for transverse and longitudinal cutting. For

3. Longitudinal milling machines After cutting, sawn timber has an uneven, rough surface, risks, warping and a number of other defects that can be eliminated by milling. In the milling process, a verified surface is also obtained, on which it is possible to align

4. Milling machines milling machines you can perform a variety of work: create profiles for parts by selecting molds, folds, grooves, ridges, etc., perform smooth edge milling, process along the perimeter window sashes, vents, transoms, door

5. Tenoning machines Tenoning machines are designed for cutting studs and lugs. By design, they are one- and two-sided. On one side tenoning machine cutting of spikes and eyes is carried out on one side of the bar, and on a bilateral one - simultaneously on both sides. On

7. Combined machines Combined machines can perform a number of different woodworking operations. The most common machines with the following combination of work: jointing - thicknessing - cutting - drilling - grinding; jointing -

TO Category:

Automotive

Drilling, countersinking, countersinking and reaming in locksmith work in the automotive industry

Drilling is the process of making a hole in a solid material with a drill. Drilling achieves the 4-5th accuracy class and roughness.

Drills by design are spiral, etc. The most widely used are spiral drills, which, according to the shape of the shank, can be with a cylindrical and conical shank. Twist drills are made mainly from high-speed steels; for drilling cast iron and materials of increased hardness, twist drills equipped with plates are used. hard alloy VK8 or solid drills made of hard alloys grades VK6M, VKYUM.

A twist drill (Fig. 0) has the shape of a cylindrical rod with a conical working end, which has two helical grooves on the sides with an inclination of 25-30 ° to the longitudinal axis of the drill. Through these grooves, the chips are discharged to the outside. Sharpening angle at

the top of the drill can be different and depends on the material being processed. For processing soft materials it should be from 80 to 90 °, for steel and cast iron 116-118 °, for very hard metals 130-140 °.

Drill sharpening. During operation, the drills wear out along the front and back surfaces, a chamfer is worked out, and the corners are rounded (Fig. 1, a). Blunt drills are sharpened on grinding machines. The control of the main elements of the cutting part is carried out by templates (Fig. 1, b).

Rice. 0. Twist drill: 1 - working part of the drill, 2 - neck, 3 - shank, 4 - foot, 5 - groove, 6 - pen, 7 - guide chamfer (ribbon), 8 - rear sharpening surface, 9 - cutting edges, 10 - jumper, 11 - cutting part

Manual drilling is carried out hand drills, electric drills and pneumatic drills.

A hand drill (Fig. 2) consists of a spindle on which the chuck is located, a bevel gear (consisting of a large and small gear wheels), fixed handle, movable handle and bib. The drill is inserted into the chuck and fixed in it. When drilling, the locksmith holds the drill with his left hand by the fixed handle, and with his right hand rotates the movable handle, resting his chest on the bib.

Rice. 1. Wear pattern (a) and a template for controlling the main elements (b) of the drill

An electric drill (Fig. 3) consists of an electric motor located in the drill body, a gear train and a spindle with a chuck in which the drill is clamped. Distinguish electric drills light type - for drilling holes with a diameter of up to 15 mm in the form of a pistol; medium type - for drilling holes with a diameter of 15-20 mm with a closed handle at the end; heavy type - for drilling holes up to 32 mm in diameter with two side handles and a chest stop.

Rice. 2. Hand drill: 1 - cartridge, 2 - gear, 3 - movable handle, 4 - bib, b - fixed handle

The pneumatic drill (Fig. 4) is manufactured with piston and rotary type pneumatic motors. The pneumatic drill is easy to use, as it has small dimensions and weight. Drilling machines are used to mechanize the drilling process.

Rice. 3. Electric drill: 1 - handle, 2 - body, 3 - spindle

Drilling machines are divided into desktop drilling, vertical drilling and radial drilling. Bench drilling machines are designed for drilling holes of small diameter (up to 12-15 mm). Radial drilling

machines are used for drilling holes in large parts. They make it possible to machine a hole anywhere in the part within the annular platform.

The most common are universal vertical drilling machines (Fig. 5). The workpiece or part to be machined is placed on a table that can be raised and lowered with a screw. The table is fixed with a handle on the frame at the required height. The drill is installed and fixed in the spindle. The spindle is driven by an electric motor through a gearbox, automatic feed is carried out by a feed box. The vertical movement of the spindle is carried out manually by a flywheel.

Rice. 4. Pneumatic drill: 1 - spindle, 2 - body, 3 - nipple

Drilling technique. Drilling is carried out according to the marking, according to the conductor, using universal prefabricated devices (USP).

When drilling by marking, mark the hole, punch it around the circumference and in the center, fix the workpiece to be processed in a vice or other device. Drilling according to the markup is usually carried out in two steps. First, a hole is drilled to a depth of a quarter of the diameter. If the resulting hole (non-through) matches the marked one, then drilling is continued, otherwise the installation of the drill is corrected and only after that drilling is continued.

When drilling a hole for a thread, it is necessary to use reference manuals to select the drill diameter in accordance with the type of thread, as well as taking into account the mechanical properties of the material being processed.

When processing a large number of identical parts, conductors are used. They consist of a body where the part is placed and oriented in a certain position, and a jig plate with holes and jig bushings pressed into them to guide the drill.

In addition to conductors, universal prefabricated fixtures (USP) are used, consisting of normalized elements (plates with T-slots, installation parts - fingers, disks, dowels, linings, guides, clamping and fasteners). From them, devices are assembled for a specific operation. At the end of the work, the devices are disassembled, and their parts are used again. USP significantly reduce the cost of processing and provide high accuracy.

Countersinking and it is called the subsequent (after drilling) processing of holes, which consists in removing burrs, removing (chamfers and obtaining a conical or cylindrical recess at the inlet of the hole. Countersinking is carried out by countersinks.

According to the shape of the cutting part, countersinks are divided into cylindrical and conical (Fig. 6, a, b). Conical countersinks are used to process conical recesses for screw heads, countersunk rivets, valves. Conical countersinks come in 60°, 75°, 90° and 120° point angles.

Cylindrical countersinks process cylindrical recesses for fasteners, boss planes. The cylindrical countersink has a guide pin that enters the hole being machined and provides right direction countersinks. Countersinks are made of high speed steel and with hard alloy plates.

Rice. 5. Single-spindle vertical drilling machine: 1 - screw, 2 - table, 3 - spindle, 4 - flywheel, 5 - feed box, 6 - speed box, 7 - electric motor, 8 - handle, 9 - frame

Countersinking and e - an operation to increase the size or change the shape of a hole obtained by drilling, stamping or casting. When countersinking, the accuracy is For - the 5th class.

Reaming of holes is performed with a countersink. By appearance a countersink resembles a drill and consists of the same basic elements, but has more cutting edges (3-4) and spiral grooves. By design, countersinks are divided into solid (Fig. 7, a), mounted (Fig. 7, b) with soldered plates and prefabricated with plug-in knives (Fig. 7, c). Materials for countersinks: high-speed steels R9, R18, R9K5, R9KYU, hard alloy plates of grades VK6, VK8, VK6M, VK8V, T5K10, T15K6. Countersinking is performed on drilling machines or using electric and pneumatic drills.

Reaming - the final processing of holes after drilling, countersinking or boring to give them high accuracy and low roughness. Deployment achieves 2-3rd accuracy classes and roughness classes.

Hole reaming is done by reaming.

According to the shape of the hole being processed, the reamers are divided into cylindrical and conical, according to the method of application - into manual and machine, according to the method of fastening - into tail and mounted ones.

Manual reamers (Fig. 58) consist of a working part and a shank. The shank is cylindrical with a square at the end for a collar. The working part is divided into cutting and calibrating. The cutting part has a conical shape with an angle of the intake cone<р = 1°, на конце для предохранения зубьев от выкрашивания делается фаска под углом 45°.

In order for the reamer to freely enter the hole, the diameter of the intake part is made smaller than the diameter of the pre-machined hole. The calibrating part directs the reamer into the hole and calibrates it, it has a cylindrical shape near the intake cone, and a reverse cone is closer to the shank to reduce friction.

Rice. 6. Countersinks: a - cylindrical, b - conical

Rice. 7. Countersinks: a - one-piece, b - mounted, c - with plug-in knives

The number of reamer teeth is even - 6, 8, 10, 12; perform them with an uneven step, which provides better processing.

Machine reamers differ from manual reamers in a shorter working part and a long neck (for reaming deep holes). Their intake cone is short with an angle cp = 5° for processing brittle materials and cp = 15° for viscous materials. Reamers equipped with hard alloys have an angle φ = 35-45°.

Conical reamers are used to taper a pre-drilled cylindrical hole or calibrate a conical hole made in another way.

Manual reamers are made of steel U12A, 9XC, R9 and R18, machine reamers are made of steel R9, R18, RK8; they are equipped with hard alloys VK2, VK4, VK6, VK8, T15K6. The working part is thermally processed.

Rice. 8. The main elements of a manual cylindrical reamer

On reamers, the nominal diameter is applied (on prefabricated - limiting diameters), the accuracy number or fit for the finished reamer, steel grade or hard alloy. On conical reamers, the nominal diameter or cone number, taper, steel grade are marked.

Manual deployment. With manual deployment, the tool rotates with knobs. For processing deep holes, extenders are put on the reamer. Small workpieces or parts are fixed in a vice, and large ones are processed without fastening.

Machine reaming is performed on drilling machines, as well as with the help of mechanized tools.

It is better to deploy immediately after drilling, without re-clamping the parts. This ensures the alignment of the holes. When working on machines, oscillating mandrels are used, they allow the reamer to self-align along the axis of the pre-machined hole and exclude the influence of machine inaccuracies on the accuracy of the hole.

TO Category: - Automotive

Drilling is the process of forming holes in a solid material with a cutting tool - a drill. Drilling is used: to obtain non-critical holes, a low degree of accuracy and a low roughness class, for example, for fixing bolts, rivets, studs, etc.;

to obtain holes for threading, reaming and countersinking.

Reaming is the increase in the size of a hole in a solid material obtained by casting, forging, stamping or other methods.

By drilling and reaming, you can get a hole of the 10th, in some cases, the 11th grade and a surface roughness of 320 80. When a higher surface quality of the hole is required, it (after drilling) is additionally reamed and reamed.

Drilling accuracy can in some cases be improved by careful adjustment of the machine, a properly sharpened drill, or drilling through a special device called a jig.

By design and purpose, drills are distinguished: spiral and special (feather or flat, for ring drilling, gun drills, combined with other tools, centering, etc.).

For drilling holes, twist drills are more often used and less often special ones.

A twist drill (Fig. 179, a, 6, c) is a two-toothed (double-blade) cutting tool, consisting of two main parts: a working one and a shank.

The working part of the drill, in turn, consists of a cylindrical (guide) and cutting parts. On the cylindrical part there are two helical grooves located one against the other. Their purpose is to remove chips from the drilled hole during the operation of the drill. The grooves on the drills have a special profile that ensures the correct formation of the cutting edges of the drill and the necessary space for the chips to exit (Fig. 180).

The shape of the groove and the angle of inclination co (omega) between the direction of the axis of the drill and the tangent to the blade should be such that, without weakening the section of the tooth, sufficient chip space and easy chip removal are provided. However, drills (especially small diameter ones) weaken with increasing helix angle. Therefore, for drills of small diameter, this angle is made smaller, for drills of large diameters - more. The angle of inclination of the helical groove of the drill is 18 - 45°. For drilling steel, use drills with a groove angle of 26 - 30 °, for drilling brittle metals (brass, bronze) - 22 - 25 °, for drilling light and ductile metals - 40 - 45 °, when processing aluminum, duralumin and electron - 45 °.

Depending on the direction of the helical grooves, twist drills are divided into right (the groove is directed along a helical line with a rise from left to right, the movement of the drill during operation occurs counterclockwise) and left (the groove is directed along a helix with a rise from right to left, the movement occurs along hour hand). Left drills are rarely used.

Located along the helical grooves of the drill, two narrow strips on the cylindrical surface of the drill are called ribbons. They serve to reduce the friction of the drill against the walls of the hole, guide the drill into the hole and help prevent the drill from drifting to the side. Drills with a diameter of 0.25 - 0.5 mm are made without ribbons.

Reducing the friction of the drill against the walls of the hole being drilled is also achieved by the fact that the working part of the drill has an inverse cone, i.e., the diameter of the drill at the cutting part is larger than at the other end of the shank. The difference between these diameters is 0.03 - 0.12 mm for every 100 mm drill. For drills equipped with carbide inserts, a reverse taper is applied from 0.1 to 0.3 mm for every 100 mm of drill length.

A tooth is a part of the drill that protrudes from the lower end and has cutting edges.

The drill tooth has a back, which is a recessed part of the outer surface of the tooth, and a back surface, which is the end surface of the tooth on the cutting part.

The surface of the groove that receives the chip pressure is called the rake face. The line of intersection of the anterior and posterior surfaces forms the cutting edge. The line formed by the intersection of the rear surfaces represents the transverse edge. Its value depends on the diameter of the drill (on average it is 0.13 of the drill diameter).

The line of intersection of the front surface with the surface of the ribbon forms the edge of the ribbon.

The cutting edges are interconnected at the core (the core is the body of the working part between the grooves) with a short transverse edge. For greater strength of the drill, the core gradually thickens from the transverse edge and towards the end of the grooves (towards the shank).

The angle between the cutting edges - the angle at the top of the drill 2φ has a significant impact on the cutting process. With its increase, the strength of the drill increases, but at the same time the feed force increases sharply. With a decrease in the angle at the top, cutting is facilitated, but the cutting part of the drill is weakened.

The value of this angle is selected depending on the hardness of the material being processed (deg):

On fig. 181 shows the angles of the twist drill. The front surface of the tooth (wedge) of the drill is formed by a spiral groove, the back - by the side surface of the cone. The geometric parameters of the cutting part of the drill are shown in fig. 182 (see section N-N).

The rake angle γ (gamma) is the angle enclosed between the cutting surface (machined surface) and the tangent to the front surface (or front face).

The presence of a rake angle facilitates the insertion of the tool, the chips are better separated and have the possibility of a natural descent.

With an increase in the rake angle, the working conditions of the tool improve, the cutting force decreases, and the tool life increases. At the same time, the body of the cutting part of the tool is weakened, which can easily crumble, break; heat dissipation deteriorates, which leads to rapid heating and loss of hardness. Therefore, certain values ​​of the rake angle are accepted for each tool. Rake angles are smaller when machining hard and tough materials, as well as when tool steels are less durable. In this case, more effort is required to remove chips and the cutting part of the tool must be stronger. When processing soft, viscous materials, the rake angles are taken more.

Clearance angle α (alpha) is the angle of inclination of the back surface formed by the tangent to the back surface (or back face) and the tangent to the machined surface. The relief angle is given to reduce the friction of the back face (or back face) against the machined surface.

At too small angles a, friction increases, the cutting force increases, the tool heats up strongly, and the back surface wears out quickly. At very large clearance angles, the tool is weakened, heat dissipation worsens.

The front and rear corners of the drill at different points of the cutting edge have different sizes; for points located closer to the outer surface of the drill, the rake angle is larger, and vice versa, for points located closer to the center, the rake angle is smaller. If at the periphery of the drill (outer diameter) it has the largest value (25 - 30 °), then as it approaches the top of the drill, it decreases to a value close to zero.

Like the rake, the clearance angle of the drill varies in magnitude for different points on the cutting edge: for points closer to the outer surface of the drill, the clearance angle is smaller, and for points closer to the center, it is larger.

The taper angle β is formed by the intersection of the anterior and posterior surfaces.

The value of the taper angle β (beta) depends on the selected values ​​of the anterior and posterior angles, since

α + β + γ = 90°.

Shanks for twist drills can be conical or cylindrical. Taper shanks have drills with a diameter of 6 to 80 mm. These shanks are formed by a Morse taper. Drills with cylindrical shanks are manufactured with a diameter of up to 20 mm. The shank is a continuation of the working part of the drill.

Drills with a tapered shank are installed directly into the bore of the machine spindle (or through adapter sleeves) and are held by friction between the shank and the walls of the tapered bore of the spindle. Drills with a cylindrical shank are fixed in the machine spindle using special chucks. At the end of the tapered shank there is a foot (see Fig. 179, a), which does not allow the drill to rotate in the spindle and serves as a stop when the drill is knocked out of the socket. Drills with a cylindrical shank have a leash (see Fig. 179, 6), designed for additional transmission of torque to the drill from the spindle.

The neck of the drill, connecting the working part with the shank, has a smaller diameter than the diameter of the working part, serves to exit the abrasive wheel during the grinding process, the brand of the drill is indicated on it.

Twist drills are made of carbon tool steel U10 and U12A, alloy steel (chromium grade 9X and chrome-silicon 9XC), high-speed P9, P18.

For the manufacture of drills, cermet hard alloys of the VK6, VK8 and T15K6 grades are increasingly used. The most common are high speed steel twist drills.

Drills equipped with hard alloy plates (Fig. 183, a, 6) are widely used in drilling and reaming cast iron, hardened steel, plastics, glass, marble and other hard materials.

Compared to drills made from carbon tool steels, they have a significantly shorter working part, a large core diameter and a smaller helix angle. These drills are highly durable and provide high productivity.

There are several types of drills with a diameter of 5 to 30 mm, equipped with hard alloys of the VK type. The bodies of these drills are made of steel grades P9, 9XC and 40X.

Helical flute drills provide significantly better chip exit from the hole, especially when drilling tough metals. This is achieved due to the fact that at a length of 1.5 -2 diameters of the drill, the helical groove is straight, and further to the tail of the drill, helical.

Drills with straight flutes are used when drilling holes in brittle metals. They are easier to manufacture, but these drills cannot be used for drilling deep holes, as it is difficult for the chips to exit the hole.

Drills with oblique flutes are used for drilling shallow holes, since the length of the flutes for chip exit is very small.

Drills with holes for supplying coolant to the cutting edges of the drill (Fig. 183, c) are designed for drilling deep holes in adverse conditions. These drills have increased resistance, since the coolant supplied under a pressure of 10–20 kgf/cm 2 into the space between the outer surface of the drill and the walls of the hole provides cooling of the cutting edges and facilitates chip removal.

The drill is mounted in a special chuck that provides coolant supply to the hole in the tail of the drill. These drills are especially effective when working with heat-resistant materials.

When drilling holes with drills with through channels, the cutting mode increases by 2 - 3 times, and tool life - by 5 - 6 times. Drilling in this way is carried out on special machines in special cartridges (Fig. 184).

Carbide solid drills are designed for processing heat-resistant steels. These types of drills can be used to work on drilling machines (the material is VK15M hard alloy) and to work on metal-cutting lathes (VK10M hard alloy).

Cases of hard-alloy drills are made of steel P9, 9XC, 40X, 45X. A groove is cut in the drills for a hard alloy plate, which is fixed with copper or brass solder.

Combined drills, such as a countersink drill, a reamer drill, a tap drill, are used for simultaneous drilling and countersinking, drilling and reaming, or drilling and threading.

Center drills are used to obtain center holes in various workpieces. They are made without a safety cone (Fig. 185, a) and with a safety cone (Fig. 185, b).

Spade drills are the easiest to manufacture; they are used for drilling non-critical holes with a diameter of up to 25 mm, mainly when processing solid forgings and castings, stepped and shaped holes. Drilling is usually carried out with ratchets and hand drills.

These drills are made from tool carbon steel U10, U12, U10A and U12A, and most often from high speed steel R9 and R18.

The spade drill has the shape of a blade with a shank. Its cutting part is triangular in shape with apex angles 2φ = 118 + 120° and back angle α = 10÷20°.

Perovye drills are divided into two-sided (Fig. 186, a) and one-sided (Fig. 186, b), the most common are bilateral. The sharpening angle of a one-sided feather drill is taken for steel in the range of 75 - 90 °, and for non-ferrous metals - 45 - 60 °. The sharpening angle of a double-sided spade drill is taken 120-135 °.

Spade drills do not allow high cutting speeds and are unsuitable for drilling large holes, since the chips from the hole are not removed, but rotate with the drill and scratch the surface of the hole. In addition, during operation, the drill quickly becomes dull, wears out, loses its cutting qualities and moves away from the axis of the hole.

13g. What is drilling and what is it based on?

Drilling is the execution of a round hole in a product or material using a special cutting tool - a drill, which, during drilling, simultaneously has rotational and translational motion along the axis of the hole being drilled.

137. Where is drilling used?

Drilling is primarily used when making holes in parts connected during assembly.

138 What types of processing receive round holes in the material, depending on the required accuracy?

Depending on the required degree of accuracy, the following types of processing are used: drilling, reaming, countersinking, reaming, boring, countersinking, centering.

139. What types of work are performed on drilling machines?

The following operations can be performed on drilling machines: drilling, reaming to a larger diameter of a previously drilled hole, countersinking, reaming, facing, countersinking, countersinking, threading.

140. In what cases does a tool (drill) make rotational and translational movements, and when - only translational?

The drill performs rotational and translational motion when working on a drilling machine, while the workpiece is stationary. The processing of parts on a lathe, automatic machine or turret is performed when the part is rotated, and the tool performs only translational movement.

141. Name the tools and fixtures for drilling.

To perform the drilling operation, drills with a conical or cylindrical shank, tapered adapter sleeves, wedges for knocking out drills, self-centering two- and three-jaw drilling chucks, handles for fastening drills in chucks, quick-clamping chucks, spring chucks with automatic shutdown of the drill, machine vice, boxes , prisms, clamps, squares, hand vices, inclined tables, as well as various types of fixtures, manual and mechanical drilling machines and drills.

142. Name the types of drilling machines.

There are drilling machines with manual and mechanical drive. Manual hand-operated drilling machines include: rotators, drills, drilling ratchets and hand-held drilling benches. Mechanically driven hand-held drilling machines include electric and pneumatic drills, which allow drilling holes in hard-to-reach places using special shanks.

Mechanically driven drilling machines include vertical drilling, radial drilling, horizontal boring and special drilling machines. Vertical drilling machines may have devices for the use of multi-spindle heads. Special drilling machines can be aggregate, multi-position and multi-spindle.

143 What are the advantages of a vertical drilling machine?

The vertical drilling machine differs from other drilling machines in that it has a bed with a vertical arrangement of guides along which the machine table can move. In addition, it has a feed mechanism, a pump for supplying coolant, as well as gearboxes for obtaining different speeds of the drilling spindle of the machine.

144. Name the maximum diameters of drills that can be used to drill holes on conventional types of drilling machines.

On vertical drilling machines (depending on the type) it is possible to drill holes with drills up to 75 mm in diameter, on bench drilling machines - with drills up to 15 mm in diameter, on table drilling machines - with drills up to 6 mm in diameter. Hand-held electric drills (depending on the type) can drill holes up to 25 mm in diameter, hand-held pneumatic drilling machines - drills up to 6 mm in diameter.

145. In what cases is a drilling ratchet used?

Drill ratchets are used for drilling holes in hard to reach places in steel structures. The manual drive, provided by the oscillatory movement of the ratchet lever, creates the rotation of the drill and its feed along the axis of the hole.

The disadvantage of drilling with a ratchet is the low productivity and high labor intensity of the process.

146. What is a drill?

A drill is a cutting tool used to make cylindrical holes (Fig. 23).

147. Name the types of drills depending on their design. 61

According to the design of the cutting part, the drills are divided into spade, with straight flutes, spiral with helical flutes, for deep drilling, centering and special.

148. Name the types of twist drills depending on their performance.

Twist drills, depending on their performance, are divided into twisted, milled, cast (for large

Diameters), with plates made of metal carbide alloys and welded.

149. What steel are drills made of?

Drills are made from tool carbon steel U10A, U12A, alloyed 9XC or from high-speed steel R18, R9, REM. Often used are drills lined with tungsten and titanium carbide alloy plates.

150 What is the accuracy class of holes made with a twist drill?

With a twist drill, holes are made to which accuracy requirements are imposed, holes intended for further processing by reaming "62

Boring or pulling, holes for threading (Table 7).

151. What elements does a twist drill consist of? The twist drill consists of a shank and a working

A part that is divided into a guide part and a cutting part. There is a neck between the guide part and the shank.

152. What is a shank and what does it serve for? The shank is a part of a cylindrical or cone-shaped drill (wood drills have a square conical shank), which serves to secure

Drills with a conical shape in conical adapter sleeves with a Morse taper, and with a cylindrical shape - in a two- or three-jaw drill chuck. The end sleeves and the drill chuck are fixed in the spindle bore. Taper shanks end with a foot that serves to knock the drill out of the spindle or taper adapter sleeve. The cylindrical shank ends with a leash. For drilling holes with drilling ratchets or hand rotators, drills with square shank are most often used. Drills with a cylindrical shank usually have small diameters (up to 20-30 mm).

153. Describe the guide part of the drill.

The guiding part of the drill is the part located

Between the neck and the cutting part. It serves to guide the drill along the axis of the hole. The guide part has helical grooves for chip removal and a drill shaft. There is a ribbon on the outer helical surface of the guide part of the drill.

154. What elements does the working part of the drill consist of?

The working part of the drill consists of a guide and a cutting part.

155. What is a drill bit?

A ribbon is a narrow belt along the helical groove, smoothly running down to the shank. The purpose of the ribbon is to take on some of the friction of the drill against the walls of the hole that occurs when the tool enters the material. The diameter of the drill is measured by the distance between the ribbons.

156. What is the cutting part of a twist drill?

The cutting part of the twist drill consists of two cutting edges connected by a third edge - the so-called transverse jumper.

157. What determines the angle at the top of the drill?

The angle of inclination of the helical groove of the drill depends on the type of material being processed (Table 8).

158. What effect does the feed force have on cutting during drilling?

The process of cutting metal with a cutting edge is carried out by cutting it into the metal, under the action of the rotation of the drill and its axial feed. The value of the angle of the cutting edge is determined by the angle of inclination of the helix and back - 64

Neem sharpening angle of the drill. The amount of the required feed force and the cutting force are determined by the size of the front and rear cutting angles and the size of the transverse edge. It is possible to reduce the required feed force during drilling by sharpening the transverse edge (bridge) and choosing the optimal cutting angle for a given material.

159. What should be done with a drill if it does not drill well?

If the drill does not drill well, it should be sharpened. Sharpening can be done manually or by machine.

Correct sharpening of the drill makes it possible to obtain the required angles, extends the life of the drill, reduces effort, and also makes it possible to obtain correctly made holes.

The selection of the cutting angles required for a given material and sharpening on special drill grinders provide the correct sharpening angles and the position of the transverse edge in the center of the drill. After sharpening, you can check the sharpening angles using a goniometer or template.

160. Describe a feather drill.

Spade drills (Fig. 23, b) are usually made of carbon tool steel U10A or U12A. The following elements are distinguished in these drills: two-sided cutting part with an angle of 116 °, one-sided - with an angle of 90-120 °, a guide part with an angle of 100-110 °, taper working part, neck and shank.

The double-sided cutting part provides a working movement when the drill rotates in both directions. The one-sided cutting part allows the drill to work in only one direction. 65

The disadvantage of these drills is the lack of a guide and a change in diameter with each sharpening. They are used for small diameter holes that do not require high precision.

Spade drills with extended pilots provide better guidance and a more accurate hole size, making it possible to obtain the same diameter until the pilot is abraded. However, these drills are inefficient.

161. What is drill feed?

Drill feed is its axial movement, mm, in the material during one complete revolution along the own axis of the drill.

162. What is the depth of cut?

The removed scrap of material characterizes the thickness of the removed layer, expressed by the formula t = y mm, where t is the depth

Cutting, d-drill diameter.

163. What is cutting speed?

The cutting speed during drilling is the circumferential speed on the drill bit, m/min, expressed by the formula

Where d is the diameter of the drill; n - the frequency of rotation of the drill per minute.

164. What should be done before drilling?

Before you start drilling, you need to properly prepare the material (mark and mark the drilling sites), the tool and the drilling machine. After fixing and checking the installation of the part on the table of the drilling machine or in another device, as well as after fixing the drill in the machine spindle, drilling is started in accordance with the instructions and labor safety requirements. We must not forget about the cooling of the drill.

165. Name defects during drilling.

Defects during the drilling process are different: it can be a breakage of the drill, chipping of the cutting edges, deviation of the drill from the axis of the hole, etc.

In table. 9 shows the types of defects, their causes, as well as ways to eliminate these defects, 66

In some cases, the jig plates have holes without jig bushings.

167. What is the purpose of drilling cooling and what coolants are used?

Cutting fluid (coolant) performs three main functions: it is a lubricant to reduce friction between the cutting tool, drill, workpiece metal and chips; is a cooling medium that intensively removes heat that occurs in the cutting zone and facilitates the removal of chips from this zone.

Coolants are used in all types of metal cutting.

Good coolant does not cause corrosion of tools, fixtures and parts, does not have a harmful effect on human skin, does not have an unpleasant odor and removes heat well. When drilling holes in steel, an aqueous solution of soap, a 5% solution of E-2 emulsion or ®ET-2 is used, when drilling in aluminum - a 5% solution of E-2 emulsion, ET-2 or a liquid of the following composition: oil " Industrial" - 50%, kerosene - 50%. When drilling small holes in cast iron, coolant is not used. When drilling deep holes in cast iron, compressed air or a 1.5% solution of E-2 or ET-2 emulsion is used. When drilling copper and alloys based on it, a 5% solution of emulsion E-2, ET-2 or industrial oil is used.

168. How are holes with a diameter of more than 30 mm made in metal?

To obtain holes with a diameter of more than 30 mm in metal or parts, double drilling should be used. The first operation is performed with a drill with a diameter of 10-12 mm, and then with a drill of the required diameter (reaming). When drilling with two holes or drilling, reaming and countersinking, cutting forces and operation times are significantly reduced.

169. How is a broken drill removed from a hole in metal?

You can remove a broken drill from the drilled hole by turning it to the side, the reverse spiral of the broken part, with tongs, if there is a protruding part of the drill. If the broken drill is inside the material, then the drilled part is heated together with the drill until it turns red, and then gradually cooled. The released drill can be unscrewed with a special tool

170. What tool is called a center drill?

A center drill is a tool used to make center holes in the end surfaces of shafts. There are two types of centering drills: for conventional center holes without a safety cone and for center holes with a safety cone (Fig. 25). The normalized angle of a conventional center drill is 60°, and with a safety cone - 60 and 120°.

On large and heavy shafts, the center recess from the ends is performed in three operations: drilling, countersinking by 60 ° and countersinking of the safety cone by 120 °.

171. What tool and when is countersinking performed?

Countersinking is an increase in the diameter of a previously drilled hole or the creation of additional surfaces. For this operation, countersinks are used, the cutting part of which has a cylindrical, conical, end or shaped surface (Fig. 26). The purpose of countersinking is to create appropriate seating in holes for rivet heads, screws or bolts, or to level the end faces.

Countersinks can be solid and with a welded shank.

172. From what materials is the core drill made?

The countersink is made of carbon tool steel UYUA, U12A, alloy steel 9XC or high speed steel P9, P12. They may have brazed tungsten carbide cutting blades. Shanks of countersinks and cases of type-setting countersinks are made of steel 45 or

173. Name the types of countersinks.

Countersinks can be solid cylindrical, conical, shaped, welded with a welded shank, solid and shell-mounted prefabricated. Countersinks of small diameters are usually made solid, and large diameters - welded or mounted. Cone countersinks have vertex angles of 60, 75, 90 and 120°.

174. What is a sweep and when is it applied? A reamer is a multi-blade cutting tool,

Used for finishing holes in order to obtain a hole with a high degree of accuracy and with a slight surface roughness.

Reamers are divided into draft and finishing. The final deployment achieves the accuracy of the 2nd-3rd class (10th-7th grade on the ESDP CMEA), and with especially careful execution - the 1st class (6th-5th grade) with a surface roughness of 7 -th-8th class of purity (Ra = 1.25 ... 0.32 microns).

175. What should be the hole diameter before reaming?

Reaming gives the final hole size required by the drawing. The reaming hole diameter should be less than the final reaming allowance (Table 10).

176. Name the types and types of sweeps.

There are the following types of reamers: according to the method of use - manual and machine, according to the form - with a cylindrical or conical working part, according to the accuracy of processing - roughing and finishing, according to the design - with a cylindrical shank, with a conical (Morse taper) shank and mounted. Attached reamers can be solid, with plug-in knives and floating. Manual reamers can be solid and expandable. Reamers can have simple and helical teeth. On fig. 27 shows manual reamers.

177. How many teeth do reamers with straight teeth have?

The number of reamer teeth depends on its diameter and purpose. So, for reamers of increased accuracy and when processing brittle materials (cast iron, bronze), the number

In other cases

G \u003d 1.51 / 0 + 2,

Where D is the reamer diameter, mm. The number of teeth in manual and machine reamers with straight teeth is most often even (for example, 8, 10, 12, 14).

178. Name the directions of the cutting edges in spiral reamers.

Reamers with spiral teeth have left- and right-handed cutting parts.

179. When are expansion and adjustable reamers used?

Expanding and adjustable reamers are used in repair work to ream holes that have different tolerances, as well as to minimize the increase in an already completed hole.

180. What is included in the set of conical reamers for obtaining sockets with a Morse taper?

The Morse taper reamer set includes three reamers: roughing, intermediate and finishing (tapered) reamers.

181. Where are boiler reamers used?

Boiler reamers are used in boiler work to enlarge holes for rivets.

182. Where are the shanks of manual three-feathers fixed

Reamers?

Three-blade hand reamers are fixed in permanent or adjustable holders.

183. Why do reamers have different cutting pitches?

In order to improve the quality of the hole and prevent its faceting, the teeth along the circumference are located at different distances from one another, i.e., an uneven pitch is used.

184. What elements does a scan consist of? The development has the following elements: the working part,

Neck and shank (tapered or cylindrical).

185. Name the coolant used in the development of holes in various materials.

In table. 11 shows the coolant compositions used when reaming holes in various materials.

Coolants are used to cool the tool, reduce friction, and increase tool life.

186. What materials are reamers made of?

For the manufacture of reamers, carbon tool steels U10A and U12A, alloyed tool steels 9XS, KhV, KhGSVF, high-speed steels R9 and R18, as well as hard alloys of the T15K6 grade for processing steel, copper and other ductile metals and grade 74 are used.

BK8 for processing cast iron and other brittle metals. High-speed steel reamers are made with welded shanks of steel 45. The bodies of prefabricated reamers, as well as adjustable and mounted ones, are made of structural steels.

187, What is a punch and in what cases are holes punched?

Punch fis. 28) is a bench tool made of U7 or U8 carbon tool steel, which is used to punch holes in sheet or strip metal or non-metal materials with a thickness of not more than 4 mm.

The working part of the punch can have a round, rectangular, square, oval or other shape. The punch for leather and sheet metal has a blind hole in the working part, which is connected to the longitudinal side hole passing through the wall of the lower part of the punch. Waste is removed through this hole.

Hole punching is performed when some damage to the surface in the area of ​​the hole is allowed and cleanliness and accuracy of the hole are not required.

188. What safety requirements should be followed when working on drilling machines?

The drilling machine must be turned on and operated in accordance with the instruction manual for the equipment, as well as in accordance with the requirements of labor safety. Special working clothes should be used, be sure to pick up hair under a headdress, especially for women.

Parts must be correctly and securely fixed in a vice or fixture that is in good technical condition. When drilling small holes, the left hand, holding the workpiece, should provide resistance opposite to the direction of rotation of the spindle. During the working stroke of the drilling spindle

The machine cannot be held or braked by the spindle, change speeds and feeds, clean the table or workpiece from chips.

The drill needs to be cooled with coolant with a brush or watering. Cooling with wet rags or rags is not allowed. The drilling machine must be turned on or stopped with dry hands. All breakdowns that can be repaired must be repaired by a trained worker. Before starting work, you should check the technical condition of the drilling machine and tools.

Marking drilling. Single holes are drilled according to the marking. To do this, the hole is pre-marked: axial lines are drawn, its center is marked and punched (the core hole of the center must be made deeper to give a preliminary direction to the drill).

In order to make sure that the direction is correct, a test drilling is made to a depth of 1/3 of the cutting part. After making sure that the drill goes in the center, turn on the mechanical feed. To avoid breakage of the drill, before the end of drilling, the mechanical feed is turned off and the drill is completed by manual feed. If the drill has taken to the side, several grooves are cut through with a cross-mesh in the place of the hole where the drill must be moved.

Drilling blind holes to a given depth. The workpiece is placed on the machine table and aligned, then the drill is brought to the surface of the workpiece so that it touches it. In this position, the parts are set to zero on the ruler available on the machine (Fig. 182, a). In the process of drilling, along the ruler, they observe how deep the drill went into the material.

Rice. 182. Drilling techniques:
a - along the ruler, b - along the stop sleeve, c - incomplete holes, d - holes at an angle to the plane, e - holes on the cylindrical surface, e - holes in hollow parts

Another way to drill to a predetermined depth is to install and fasten the bushing-stop 1 on the drill (Fig. 182, b). When the sleeve reaches the surface of part 2, the hole has been drilled to the required depth.

Drilling partial holes. A hole that has an arc in cross section equal to half a circle or less than a semicircle is called incomplete, for example, a hole located at the edge of the part. An incomplete hole is drilled as follows. A plate of the same material is attached to the workpiece, clamped in a vise (Fig. 182, c) and a full hole is drilled, then the plate is discarded.

Drilling holes in planes located at an angle(Fig. 182, d). So that the drill does not deviate to the sides and does not break, first prepare the site perpendicular to the axis of the hole being drilled (milled or countersinked), wooden liners or linings are inserted between the planes, then the hole is drilled in the usual way.

Drilling holes on a cylindrical surface. First, a platform is made perpendicular to the drilling axis on a cylindrical surface, the center is punched, after which a hole is drilled in the usual way (Fig. 182, e).

Drilling holes in sheet metal. Drilling a hole in thin sheet metal with conventional drills is very difficult, since the drilling depth is less than the length of the intake cone: the cutting edges of the drill will cling to the material being processed and tear it. Holes in sheet metal are drilled with spade drills. Most often, holes in thin sheet metal are punched on punching presses.

Drilling hollow parts. When drilling hollow parts, the cavity is clogged with a wooden plug (Fig. 182, e).

Deep hole drilling. To drill deep holes (the depth is more than 6-8 drill diameters), a drill is taken, the length of the working part of which is greater than the drilling depth.

During the drilling process, it is necessary from time to time to remove the drill from the hole to cool it and remove chips with a jet of coolant, a magnet, or by turning the part over.

When drilling holes of very large depth, you must first drill a hole at a given diameter to a depth equal to the length of the working part of the drill, and then drill through with a drill of a smaller diameter (about 1.5 times). After that, the hole is finally drilled with a feather drill. With this method of drilling, the chips will be removed through the previously drilled hole. Drilling a hole of great depth on both sides is not recommended.

Drilling precise holes. To obtain accurate holes, drilling is carried out in two passes. The first pass is made with a drill, the diameter of which is 1-3 mm less than the diameter of the hole, and the second - with a drill of the required diameter.

To obtain cleaner holes, drilling is carried out with a small automatic feed with abundant cooling and continuous chip removal.

Drilling holes in plastics is done with drills with special sharpening angles. Organic glass is drilled with twist drills with a tip angle of 50-60°.

Drilling holes of small diameters is carried out on high-precision machines with appropriate feeds or by ultrasonic and electric spark methods.

Drilling holes of large diameters is carried out with annular drills, in the body of which knives are fixed.

The reasons for marriage during drilling and measures to prevent it are given in Table 3.

Table 3
Causes and measures to prevent marriage during drilling

When working on a drilling machine, the following safety precautions must be observed:

• correctly install, securely fix the workpieces on the machine table and do not hold them with your hands during processing;
• do not leave the key in the drill chuck after changing the cutting tool;
• start the machine only when there is a firm confidence in the safety of work;
• monitor the operation of the pump and the amount of coolant entering the processing site;
• do not take on the rotating cutting tool and spindle; do not remove broken cutting tools from the hole by hand, use special tools for this;
• do not press hard on the feed lever when drilling workpieces for a pass, especially when drilling with small diameter drills;
• put a wooden lining on the machine table, under the spindle when changing a chuck or drill;
• use a special key, a wedge to remove the drill chuck, drill or adapter sleeve from the spindle;
• constantly monitor the serviceability of the cutting tool and the devices for fastening workpieces and tools;
• do not transmit or receive any items through a working machine; do not work on the machine in gloves; do not lean on the machine while it is in operation.

Be sure to stop the machine if:

• a) leaving the machine even for a short time;
• b) termination of work;
• c) detection of malfunctions in the machine, accessories, fixtures and cutting tools;
• d) when lubricating the machine;
• e) installation or change of cutting tools and fixtures, accessories, etc.;
• f) cleaning the machine, workplace and chips from the tool, chuck and workpiece.