Tool for chiselling and cutting. Mortising tools and techniques for working with them. Preparation of chisels and chisels for work

22.05.2015

   The mortising tool is designed to select square and oblong rectangular nests in details for spike connections. Combining it into a group is carried out according to its intended purpose, since according to the design and kinematics of cutting, certain types of mortising tools differ greatly from each other. In woodworking, the following types of mortising tools are used.
Simple machine bits  (Fig. 59, a) are currently rarely used and only on mortising machines of obsolete designs. They are inefficient and use them to sample nests 4–40 mm wide.
Hollow square drill bits  (Fig. 59, b) - combined tools, consisting of a hollow chisel and drill. As a drill, screw and screw drills are used. The width of the bit is 6-30 mm with a gradation of 2 mm. A hollow chisel provides the greatest accuracy of the selected nests, but it is not widespread due to low productivity.
Mortising Chains  (Fig. 59, c) are a continuous chain with cutter links, driven by a four- or six-tooth drive sprocket relative to the guide bar with a guide roller at the end. The cutting process when sampling oblong rectangular nests with chains is a milling process, whence the name of this type of mortising tool comes from. Guide rulers are distinguished by shape and size. Each width of the cutting chain, which determines the width of the socket, corresponds to a set of a guide ruler and a single or double sprocket (depending on the chain design: three- or five-row).

Milling chains for selecting a nest with a width of 6 to 16 mm consist of three tooth plates in one joint; from 18 to 20 mm - from five and from 25 to 30 mm - from seven plates. The pitch of the chain links is 11.3 mm. The dimensions of the nest when hollowed with milling chains range from 6x40x100 mm to 25x55x140 mm with a gradation of 2 mm in width. The angular parameters of the chain cutters are taken in the following limits: α \u003d 15 °; β \u003d 55/65 °; γ \u003d 11/20 °; δ \u003d 70/75 °. Larger cutting angles relate to hard rock processing. During operation, the chain should be tensioned with a force of 10 kgf.
The durability of the milling chains and guide lines largely depends on their proper operation. During operation, the guide ruler and chain should be lubricated periodically with liquid oil, and the roller should be lubricated with grease using a cap grease gun mounted on the ruler. At the end of work, the chain is washed in kerosene, dried and lubricated after sharpening by immersion in heated mineral oil. Mortising chains are the most productive mortising tool.
Nesting milling cutters (Fig. 59, d) and a combined mortising tool with a two-blade chisel and mortars (Fig. 59, d) are intended for sampling nests with dimensions: 12-80 mm in length, 2-20 mm in width and 20-100 mm, in height, These types of tools are very promising in the manufacture of furniture requiring high precision machining.

The slotter designed for metal work is equipment with which it is possible to process hard-to-reach spots in metal parts. The main purpose of such equipment, which belongs to the category of highly specialized, is to create elements of various profiles, which is carried out due to the extraction of metal. Along with professional ones, there are also home-made machines of this type, but the principle of their work is practically the same.

Features of slotting machines

Both professional and home-made mortising machines consist of the same structural elements, which allow such equipment to effectively carry out all the functions assigned to it. The basis of any mortising machine is a bed on which its other structural elements are mounted: a work table, a dolby - a tool with sharp teeth, a rocker mechanism, a feed box, a drive that can be mechanical, electric and hydraulic.

Hydraulic drives are equipped with serial mortising machines, which are considered professional equipment. To work on such more advanced equipment, due to the presence of a hydraulic drive, is much simpler and more convenient. Homemade metal chiselling machine has a simpler design, but at the same time is able to successfully cope with many technological operations.

The working principle of the mortising machine is shown in the video:

The design of professional mortising machines has a number of important elements: a cooling system, systems responsible for managing equipment and ensuring the smooth operation of all components of the device. The hydraulic drive of the machine is located inside its bed, and the programming of its work using a special system allows the slider, which performs reciprocating movements, to execute them according to precisely specified parameters.

The slotter for metal allows you to perform a whole list of technological operations: the formation of keyways, grooves and slots on the surfaces of both flat and shaped type, receiving cuts and grooves in cylindrical and conical holes. You can use such a machine for processing external surfaces whose height does not exceed 320 mm, as well as internal surfaces with a depth of not more than 250 mm.

Moving the desktop of this equipment can be achieved using manual or mechanical transmission, and can also be performed in a straight line or in a circle, which makes it possible to perform processing of gear wheels and other round metal parts on such a machine. Unlike a professional, a home-made machine can process parts in only two planes, which significantly reduces its functionality.

The principle of operation of the mortising machine

Processing of metal parts on a mortising machine is carried out due to the reciprocating movement, which in the vertical plane makes the slider and the cutter fixed in it. The working supply of the workpiece is carried out due to the movement of the table on which it is fixed.

The slotter can work in two main modes: simple and complex. In simple mode, a metal billet is machined point-blank, and the cutter, moving to the required distances, creates a series of holes that do not differ in their shapes and sizes. The difficult mode involves processing holes at an angle and hard-to-reach surfaces located in the inner part of the workpieces. Such operations can only be performed with professional equipment. A DIY machine is not suitable for them.

Do-it-yourself mortising machines are ideally suited for equipping small industries and private workshops, where they can be used to process blanks of non-ferrous and ferrous metals. For large-scale production, professional equipment is required, often equipped with numerical control (CNC).

To get an idea of \u200b\u200bhow grooving cutters look for the corresponding machines, see the photo below:

Basic models of machines

The most popular and widespread model of a mortising machine for metal is "GD", which is represented by the 200 and 500 series. The more modern and functional is the mortising machine model S315TGI, which is also very popular among domestic manufacturers. Such a machine, unlike simpler models and devices made by hand, can effectively carry out a large list of technological operations for metal.

When choosing serial mortising machines, you can’t just focus on promotional videos, a number of important parameters should be taken into account. One of the most important characteristics is the maximum workpiece height that can be machined. Significant parameters of such a metal machine are also: power, tool size and the ability to adjust it, the presence of a longitudinal and transverse stroke, an allowable angle of inclination, and parameters of the speed of the cutter. When choosing such a machine, you should also pay attention to its dimensions and weight, affecting its stability and ease of maintenance, to be equipped with additional devices that significantly increase the functionality of the device.

Do-it-yourself mortising machine

To make a do-it-yourself mortising machine with your own hands, at least, you need a drawing of it. Any such equipment, in fact, is a vertical-planing machine with a manual drive. All structural elements of such a machine are placed on a massive base (350x350x20 mm), which is also its working table.

On the basis of such a home-made machine, a stand made of a steel rod with a diameter of 40 mm and a height of 450-500 mm is fixed. A longitudinal groove is cut through the entire height of the rack, and a groove is made at one of its ends, which is necessary for its connection with the flange. Such a flange, which is a massive washer with one central hole and three fasteners located around its circumference, is necessary to ensure reliable fastening of the rack to the base. The stand is inserted into the flange with its machined end and is securely fixed in it by means of a welded joint, and the flange itself is attached to the base of the machine using a threaded connection.

Drawings of a manual slotting machine with which you can cut slots and grooves:

General scheme of the machine Console Toolholder Toolholder Caliper

A holder and a console are mounted on the console, between which a compression spring is installed. A fairly complex device is the console, the design of which consists of two hollow cylinders: a mandrel and a rack, by welding connected by a jumper (a square pipe with a section of 60x60x2.5). A hole with an M12 thread is made in each of the cylinders, which are necessary for the fixing screw that keeps the console from turning (in the rack cylinder) and for installing the locking screw in the mandrel cylinder. On two opposite sides of the rack-mounted cylinder, it is necessary to weld the axles for the tool feed levers, which are made of half-studs or screws with M12 thread.

The levers and thrusts of such a home-made mortising machine themselves are made of a steel strip with dimensions of 30x8 mm. Fastened together pivotally by bolts, axles, levers and rods are put on the axis of the mandrel cylinder and holder.

It should be noted right away that on a mortising machine made by one's own hands, it is possible to process a metal part to a depth of 0.2-0.3 mm in one pass.

We should also talk about the support of such a machine, which looks like a machine vice. The metal blanks to be processed are mounted in a three-jaw lathe chuck mounted on the upper movable platform of the support. With the help of such a support, which is reliable and easy to operate, the workpiece is fed with respect to the cutting tool to the working depth.

An example of another homemade product made on its own.

Chisels and chisels are used for chiselling nests, stripping edges and trimming planes, spikes, eyes, cutting veneers (Fig. 4.1-4.9). The industry produces bits from 6 to 22 mm with a gradation of 2 mm, and chisels from 6 to 20 mm with a gradation of 2 mm and from 20 to 40 mm with a gradation of 5 mm. Such a set is sufficient for household and construction work, but for carpentry, narrow chisels from 1 to 6 mm with a gradation of 1 mm are still required.

The chisel differs from the chisel in a larger thickness and a handle with a shackle on top, protecting the tree from destruction by a hammer. In carpentry practice, strong blows are not required, since deep nests are usually first drilled and then cleared. Hammering with strokes is inherent in carpentry, thin carpentry parts can also be split. Therefore, it is enough for the joiner to have a set of chisels from 2 to 16 mm and two wide chisels 25 and 40 mm, as well as two chisels 6 and 12 mm.

Fig. 4. Tools for chiselling and drilling:
1 - bit; 2 - wide forged chisel: a - insertion of the tail into the workpiece of the pin; 3 - narrow chisel; 4 - a semicircular chisel with an external chamfer; 5 - the same, with an internal chamfer; 6 - a flat rezchitsky chisel; 7 - klukarza; 8 - rounded chisel chisel; 9 - a corner chisel; 10 - perk; 11 - rot; 12 - manual screw drill; 13 - spiral drill on wood; 14 - cork drill (head); 15 - spiral drill; 16 - countersink

Narrow chisels are made of spring wire, files, grinding them accordingly on an emery wheel. With the exception of the cutting end, the metal should be “released" by heating in a low flame until yellowness appears on the cleaned surface of the chisel (about 160 ° C). If this is not done, then the chisel will turn out to be fragile, since the file metal is hardened along its entire length.

The pins are mounted on the pins - wooden handles of rectangular cross section with barrel-shaped rounded edges. (Round handles are less convenient.) Handles need to be cleaned and polished or varnished with oil. The nozzle should be parallel to the cutting edge of the tool, this helps accuracy in work. For stubs, they take strong viscous wood - dogwood, beech, twisted birch. To fit precisely, the hole is first drilled, observing the direction of the ribs, to a depth of 112 of the shank, and then burned deep into the hot shank, not fully completed. A chisel driven in this way will sit firmly. Obliquely driven handles are fixed by cutting the excess from the right side. Therefore, the handle blank should be made slightly larger in order to be able to correct it.

Chisels are stamped, punching (thin) and forged (thick). Forged ones are characterized by a special tide - emphasis and slight thinning of the pen to the cutting edge. Stamped - have parallel wide edges and require the installation of a thrust washer so that the handle does not stuff on the shank during impacts.

The quality of the chisel depends on steel and hardening. A sharpened chisel should cut 15 cm of beech or oak timber without blunting. If steel wraps or crumbles, the tool should not be used. Sometimes it is possible to improve the metal with a new hardening. The low cost of the chisels allows you to make a choice until you get the right qualities. As a rule, forged chisels are more reliable.

The length of the chisel is selected based on strength conditions: a very long and thin chisel is easy to break. Usually the length of the cutting part is 10-15 cm. Only for some works, for example, when chiselling notches in planers or jointer planes under the knife, the length of the pen is 20-22 cm. The feather in the broad face should be slightly wider by the end (1-2 mm) . It is difficult to work with wedge-shaped chisels, they get stuck in the nest and make the work sloppy. The angle of sharpening wide chisels 20-25 °, narrow - 15-20 °. In the first case, the bevel width should be 2.5 thicknesses, in the second - 3-3.5 thickness of the chisel at the cutting end.

To select the rounded recesses, semicircular chisels of different radius of curvature are used - from almost flat to semicircular. Sharpen them both externally and internally, depending on the nature of the work ahead. In addition, for simple carvings, chisels with a slanting edge are used, shorter and thinner, as well as semicircular, curved like a scoop, the so-called klukarzy. The industry does not produce this tool; it is made in a cunning, blacksmithing way, from bearing rings, springs or thick springs.

Chiselling is the process of removing unnecessary wood from a workpiece by inserting chisels or chisels into it. Using hollowing in the blanks, nests, grooves and eyes are selected.

Slotting tools

For chiselling, chisels and chisels (flat and semicircular) are used.

Joiner's chisel  consists of a steel sheet, a handle, a ring and a cap (Fig. 1.35, but).  The bit handle is made of hardwood or impact-resistant plastic. Chisels are made with a length of 315, 335 and 350 mm with a width of blades of 6 ... 20 mm. The angle of sharpening of the chamfer of the bit is 25 ... 30 °, and the angle of sharpening of the side faces is 10 °.

For sampling small nests, stripping quarters, grooves, spikes, eyelets, chamfering and fitting joints of wooden parts, use flat chisels  (Fig. 1.35, b)

When processing rounded surfaces of workpieces and nests semicircular chisels.

The length of the chisels is 240, 250 and 265 mm; the width of flat chisels - 4 ... 50 mm, semicircular - 4 ... 40 mm; sharpening angle - 25 ... 30 °.

Preparation of chisels and chisels for work

Chisels are sharpened on a mechanical sharpener, ruled on a whetstone and a donkey, as are planer knives. The sharpening of the bit must be one-sided with a chamfer and a rectangular blade. Flat chisels are sharpened in the same way as chisels, with a cutter angle of 25 ... 30 °. The semicircular chisel blades are ground with a whetstone and a personal file.

Wood Chiselling Techniques

To obtain a through socket, it is preliminarily marked out on two opposite sides of the workpiece, and non-through - on one side. When through hollowing, a board is placed under the workpiece so as not to damage the lid of the workbench. Recessing techniques are shown in Fig. 1.36. The bit is selected according to the width of the marked nest, placed vertically near the nearest marking line (chamfer inward), departing from the line by a distance of 1 ... 2 mm, after which the first blow is applied to the bit with a mallet and then the second blow to the bit tilted into the socket and cut off the first shavings. Then repeat the same and hollow out approximately 2/3 of the length of the socket. Then the chiselling process is continued at the opposite marking line. Then the workpiece is turned over and chiselled on the opposite side in the same sequence. It is undesirable to cut thick chips when chiselling, as as a result

  this deteriorates the quality of the workpiece.

Chisel cutting techniques

  When trimming and cleaning surfaces, the chisel is held in the girth with the palm of the right hand at the end of the handle, and the palm of the left hand is wrapped around the chisel. With the right hand, they press the end of the handle, as a result of which the chisel cuts into the wood and moves forward. With the left hand, adjust the thickness of the removed chips and the cutting direction. At the same time, to make cutting easier, the cutting edge of the chisel is placed at an acute angle to the wood fibers. Chisel cutting techniques are shown in Fig. 1.37.

Safety

Careless handling of the chisel and chisel and non-observance of labor safety rules can cause serious injuries. When working with a chisel and a chisel, it is forbidden to cut onto yourself, on weight, with the emphasis of the part in the chest, with the location of the part on the knees. When cutting a chisel, the fingers of the left hand should always be behind the blade. Before starting work, make sure that the chisels and chisels are well and correctly sharpened. A chisel or chisel can be passed alongside only the handle, not the blade forward. On wooden handles of chisels and chisels there should not be chips, cracks, sharp corners and other defects that can lead to injury to the skin of the hands of the worker.

Useful advice to the joiner

To make it easier to recess the nest in the workpiece, it is necessary to moisten the selected area by putting a rag moistened with hot water on it. After wetting the upper layer, it is easily removed with a chisel. Then the soaking is repeated and hollowed out until the nest reaches the desired size.

Wood drilling

Drilling is a carpentry operation performed to obtain round holes for pins, screws, bolts and other pivotal fasteners of wooden parts. Drilling also removes wood defects - knots with their subsequent sealing with wooden corks on glue. Drills are used for drilling wood: spiral, center, screw and countersink (Fig. 1.38).

Drilling tools

For drilling using various types of drills.

Twist drills  with conical sharpening (see Fig. 1.38, but)used for drilling wood along and across the fibers, as well as at an angle to the surface of the part. Twist drills with a guiding center and cutters (see Fig. 1.38, b)  serve to drill wood across the fibers. Twist drills have helical grooves on the surface of the shaft to remove chips from the hole. They choose deep and precise holes.

Center drills  with flat (see Fig. 1.38, at)  and a cylindrical head (see Fig. 1.38, d)  are used for drilling through and shallow holes across the fibers in wood. Center drills with a cylindrical head are also used for drilling holes for hinge loops. Center drills drill shallow holes with a diameter of 12 ... 50 mm. Such a drill consists of a core with downward cutters, a cutting edge (blade) and a guiding center (tip).

During operation, the drill often has to be removed from the hole to remove chips.

Auger drills  (see Fig. 1.38, e)  used for drilling wood across the fibers. The diameter of screw drills is 10 ... 30 mm.

Countersink drills,  or countersinks  (see Fig. 1.38, e)  serve for countersinking holes for screws and bolts.

Preparation of drills for work

Drills are sharpened with fine-grained grinding wheels on a sharpener or manually files. When sharpening with a file, the hardness of the drill should be less than the hardness of the file. The cutting blade of the drills with the guide center is sharpened from the back side, the cutter is on the inside, the guide center is along the edges of the pyramid. In spiral drills with conical sharpening, the back face is grind along the generatrix of the cone. Sharpening
  made manually or using sharpening devices.

Hole Drilling Techniques

  When drilling a hole, the drill must make two movements: rotational (clockwise) and translational (deep into the hole). To rotate the drill, it is better to use a rotary collar with a ratchet (Fig. 1.39), which is a cranked rod in the middle of which there is a handle for its rotation. A push head is located at the upper end of the shaft, and a chuck for attaching the drill is located at the lower end. Kolovorot should rotate to the right and to the left. The direction of its rotation is set by a ring - switch. Screws, bolts and nuts can be wound with a collar if a screwdriver or socket wrench is inserted into the chuck. You can drill holes up to 10 mm in diameter with a rotary swivel. Drilling techniques using a rotary rotor are shown in Fig. 1.40. In addition to the rotor, a manual drill is used for manual drilling (Fig. 1.41).

To perform drilling, the workpiece is fixed on a workbench, then the center of the hole is marked and punctured with an awl. After determining the center of the hole, drilling begins. Through holes in thick parts are usually drilled from two sides. In thin workpieces, one-sided through drilling is made with a backing board on the reverse side. When drilling at an angle to the surface of the workpiece, a vertical hole is first drilled to a shallow depth, and then the drill, without stopping rotation, is rotated at the desired angle to the surface of the workpiece. When drilling at an angle, you can first
  cut down the top of the nest with a chisel, and then drill.

Often, overhead templates are used to drill several holes, which have holes of the required diameter and exclude marking. Patterns (conductors) made of hardwood, are bars in which 2 ... 3 holes are drilled equal to the diameter of the drill. The conductors are fixed on the workpiece with a clamp and drilled holes to the desired depth. The resulting holes should have an exact size, and their axis should be strictly perpendicular to the upper surface of the workpiece. When drilling wood, you need to use correctly sharpened drills without cracks and defects. The drill must be fed deep into the hole easily and smoothly.