Elements of a hacksaw: what are the main parts
The instrument has become popular also because of its structure. Outwardly, it resembles the letter C, to the ends of which a cutting blade is fixed. This tool contains the following elements:
- A pen. Modern hand saws have handles that are made using two-component materials. This allows for a longer tool life. The shape of the handle is made in such a way that it is very convenient to use it. Usually it is located either at the top or on the side. In the first case, the tool is used to work in places where it is difficult to get close.
- Frame. It takes on the main load. It is she who extinguishes all vibrations that arise during work. Modern hacksaw frames are made from a wide variety of materials. Very often, an element is installed on the tool that regulates the tilt of the blade, which allows you to work in places with difficult access. The frames are made in two versions. They can be solid or have the ability to move apart. It is possible to put a canvas of any length on a sliding frame.
- Canvas. To cut metal, it is made from very hard alloys. It is very thin and fragile. There are many small teeth along the entire length. The work requires special care. You need to buy a canvas that is hardened. If it is not there, then it will fail very quickly. The element with sparse teeth is more efficient. A high-quality cut can be provided only by the one in which the teeth are often located. Recently, bimetallic blades began to appear on sale.
Scope of application of the hacksaw
Tools are made not only by hand, but also electric. Their main task is to cut metal. Naturally, you can make grooves with them, as well as much more. The canvas is made of various materials, therefore, its properties may be different. A locksaw’s hacksaw is available not only for sawing metal parts. By changing the type of blade, you can cut objects made of plastic, ceramic or plexiglass. Among the entire range of hacksaws, there are three main types:
- For household use. Such models are the most common. They are ideal if you need to do something that is not very difficult. It is very easy to use them. To fix it, you need to insert it into the grooves and tighten the special screws. The main thing is to remember that the canvas should be well stretched so as not to damage it during operation. Such hacksaws are much cheaper than the others.
- Hand tools are also of a professional type. They are used when you have to work for a long time, and the cut must be clean and even. A feature of such tools is a convenient handle, as well as a mechanism for quickly changing the saw element. If you need to cut something very often, then it is better to use just such models.
- Hacksaw handle. The appearance of this tool resembles a staple. They do not need to have great physical strength to work. They use it exclusively where it is simply impossible to crawl with the usual variety. Due to its design, it is permissible to install broken blades into a locksaw.
What are the main parts of a hacksaw
Any owner has, albeit a minimal, but set of tools. It is individual for everyone, but everyone has a hacksaw for wood and metal. Its main parts are a handle, a frame, a canvas.
Features of using a hacksaw
To work the tool comfortably, you need to stand in front of the vice with a half-side. The left leg should be in front. It is she who is the supporting one. The handle rests on the palm of the right hand, with the thumb it is held on top, and the rest is wrapped around the bottom. Place your left hand on the front end of the hacksaw.
When working with a saw, it is usually held horizontally. The movements are smooth, you should not pull. The scope of the tool is needed such that the entire length of the blade takes part in the process. As a rule, two-thirds of the length is involved in the working rhythm.
A typical hacksaw speed is up to sixty strokes per minute. Moving is meant moving forward and backward. At the same time, when working with hard metals, the speed decreases, and soft ones are cut faster.
When the hacksaw goes forward, you should press on it, it comes back easily. Its strength should match the hardness of the metal under the saw blade. The harder it is, the more pressure is needed. Under normal conditions, 0.1 millimeter of the thickness of the web has a pressure of one kilogram. At the end of the process, when the part is almost cut, the pressure should be loosened.
Hand tools, as a rule, do not need cooling after work. To reduce friction, grease is applied to the cut.
If the blade is not tight enough, then the tool is often pulled to the side. This can negatively affect not only the evenness of the saw cut, but also the integrity of the cutting element itself. If this happens, it is best to back off and start a new cut. If you try to fix a cut that has gone to the side, it will lead to damage.
Incorrect hardening of the hacksaw blade contributes to tooth breakage. This can happen if the tool is pressed very hard or if the metal is interspersed with harder particles.
If even one of the teeth breaks, it is better to immediately change the blade, because others will break behind it. You can use the old one, but then you need to restore it first. For this, the nearest teeth are ground near the broken tooth. It will be enough to grind off two or three. After this procedure, you can use the canvas again.
What is a hacksaw for??
Having dealt with the definition of what a hacksaw is, it is worth dwelling in more detail on the areas of its application:
- This tool is widely used in horticulture for pruning trees and shrubs, cutting knots and rough parts of wood.
- A hacksaw is used to cut wooden parts during construction and household repairs.
- She cut out figures from plywood, make curved cuts or make through holes.
- There are special varieties for sawing metal sheets and pipes, aerated concrete blocks.
- Some modifications cut grooves, spikes and recessed holes.
How to sharpen a hacksaw?
After carrying out a certain amount of work with a hacksaw, the saw teeth are simply dull. The first signs of the need for sharpening include:
- Heavy and uneven sawing.
- Uneven cut.
- The web often gets stuck.
- It is difficult to keep the given trajectory.
When the above “symptoms” appear, each master must understand how to sharpen a hacksaw while maintaining the working profile of the teeth:
- Clamp the tool securely in a vise or clamp.
- Carry out the setting of the teeth. This procedure involves alternately bending each tooth in different directions by the same amount by about 1.5-2 mm with a special tool.
- A triangular file with a fine cut is selected.
- The angle of sharpening of the teeth is determined by eye, which is approximately equal to 15-30º.
- Carry out the same number of file strokes in the selected direction on one side. Repeat the process for the other side.
- The teeth are aligned in height.
A special type of tool that has appeared relatively recently is a cordless reciprocating saw, which is also called an electric hacksaw. Such a device will come in handy when performing a large number of construction or garden work. The compact size allows the electric hacker to be used in confined spaces that would be difficult to handle with a conventional saw. Such a hacksaw should be selected, guided by the following characteristics:
- Battery capacity, which directly affects battery life. Professional models can last about 5 hours before changing the battery.
- Voltage affecting the power and number of movements made by the saw per unit of time.
- The ability to connect additional batteries to increase performance.
Types of hacksaw teeth
All the models described above differ not only in the shape of the blade for a hacksaw for metal or wood, but also in the size and angle of sharpening of the teeth. In terms of shape and sharpening, all teeth are divided into:
- Rip sawing equipment along the grain. It has large, right-angle sharpened teeth.
- For crosscutting layers of workpieces. Tooth edges are sharpened at an angle and slightly slanted back.
- The so-called Japanese cross-cut teeth. They differ from the standard counterpart in longer teeth and a double slope of the cutting edge.
- Symmetrical universal teeth, sharpened along the edges. Suitable for ripping and cross cutting.
The size of the teeth are:
- Small, about 2-2.5 mm long.
- Medium, the size of which is in the region of 3-3.5 mm.
- Teeth with a length of 4-6 mm are considered large.
Hacksaw. what is it, a device, what is it for, how it differs from a saw, the main types
One of the main tools for working with various materials from a home craftsman is a hacksaw. It has several varieties, which are used depending on the type of surface to be treated. It is important for each of them to be able to use correctly.
Types of hacksaws
The whole variety of hacksaws can be roughly divided into tools for:
- Works with wood surfaces. This includes both the universal saw and the garden hacksaw, and some other special varieties.
- Metal surface treatments. This group also has its own modifications for masters of different classes.
Works with aerated concrete
By structure, the instrument is:
- Standard single handle.
- Modifications with a solid frame are found.
- A specialized tool is a folding hacksaw, which is an attribute of the traveler’s tool kit.
What is a hacksaw?
In joinery, a hacksaw is a special type of hand saw designed for sawing wood, metal, aerated concrete, plastic and other materials. Scientists find mentions of the first such instruments in ancient times in the civilizations of Egypt, Greece and Rome. During the centuries-old history, the hacksaw has undergone significant changes, but has not lost its relevance and is always stored in the set of basic tools of the home craftsman.
Practice report: Locksmith, mechanical, dismantling and assembly work
Bending and straightening of metal.
Assembly and disassembly operations.
The repair ensures the restoration and maintenance of the operability of the rolling stock of road transport, the elimination of failures and malfunctions that have arisen in operation or identified during maintenance. During repairs, faulty units, assemblies and parts are replaced with serviceable ones, taken from the circulating fund, and also carry out disassembly, adjustment, assembly, locksmith, mechanical, welding, electrical and other types of work. 2. Technical measurements. Multidimensional fixed tools: a) folding metal meter. accuracy up to 0.5 mm. b) Steel scale bar. accuracy up to 0.5 mm. The rulers are 150, 200, 300, 500, 750 and 1000 mm long. C) Probe. used to determine the gap in the joints of parts during assembly. Usually has a set of up to 10-20 plates with a thickness of 0.05 to 2 mm.
a) Vernier caliper. accuracy up to 0.1 mm sometimes accuracy up to 0.05 mm. It is designed to measure external and internal dimensions: thickness, depth, diameter. (ШЦ-I. accuracy up to 0.1 mm. ШЦ-II. Accuracy up to 0.05 mm.
SHTs-III. accuracy up to 0.1-0.05 mm). It consists of a rod, fixed jaw, movable jaw, frame, clamp, micrometer feed frame, nut and screw, depth gauge.
b) Micrometer. used to measure the thickness of the sheet (metal) accuracy up to 0.01mm. It consists of a bracket, a micrometer screw, a stem sleeve, a fixed heel, a ratchet, a drum.
One-dimensional instruments: Gauges are extremely smooth, non-adjustable. used to measure the outer dimensions of parts (in the form of staples) and to measure the inner dimensions of parts (in the form of plugs). Tools for measuring angles: a) Squares. serve to check the correctness of the angles, as well as the flatness of the machined surface. come with angles 90, 60, 120, 135. b) Malka. measure the angle between the edges of the part. All measurements with these tools are carried out in direct contact with the part being measured.
What was measured: Measurement with a caliper and a micrometer of the “Stepped shaft” part.
What tool: Measuring vernier caliper ШЦ-I, ШЦ-II, micrometer 0-25
With what accuracy: ШЦ-I. accuracy up to 0.1 mm. ШЦ-II. accuracy up to 0.05 mm. Micrometers with measuring ranges from 0-25mm to 477-500mm.
Sequence of markup execution:
It is necessary to carefully study the working drawing of the part to determine the suitability of the material and find out the technological process of manufacturing the part. Having understood the working drawing, you should draw up a layout plan, i.e. finding the method and order of drawing lines on the marked material and punching them.
Before proceeding with the marking, they carefully check whether the workpiece has defects: cracks, cavities, gas bubbles, distortions and other defects, and also check the dimensions and processing allowances with the drawing. Blanks from sheet, strip and round material must be aligned on a special plate with hammer blows or under a press.Before installing the blank or part on the marking plate, those surfaces on which the marking marks should be applied are covered with chalk, diluted inlet to the thickness of milk; wood glue (for bonding) and desiccant (for quick drying) are added to this solution. The surfaces of purely processed workpieces are painted with a solution of copper sulfate. After the solution dries, a thin and very strong copper layer remains on the surface of the part, on which the marking marks are clearly visible. Marking parts have to be painted, because a scribe, thickness gauge or compass leave a very dull mark on unpainted surfaces. If the marked places are covered with one of the above solutions, then the risks against the background of the paint are clearly visible and persist for a long time.To measure when marking the lengths, steel rulers with millimeter divisions are used. For straight lines, it is recommended to use a steel ruler with a beveled side; such a ruler is applied with the beveled side directly to the part to be marked and the dimensions are transferred from it. When measuring long lengths, it is recommended to use a steel tape. When laying down dimensions vertically, it is convenient to use a scale ruler with a stand. The measurement accuracy with this ruler is 0.5. 1.0 mm. The angular caliper allows you to determine the hypotenuse of a right triangle for given legs without calculations. This caliper is convenient to use in cases where you need to postpone the size between two points that do not lie in the same plane, but are interconnected by the dimensions L and L. Risks are usually applied in the following order: first all horizontal risks, then vertical, then oblique risks and last but not least, circles, arcs and rounds. Spatial markup is used for graphic constructions carried out on the surfaces of workpieces and parts located in different planes at different angles to each other. In its techniques, spatial marking is significantly different from planar. The difficulty of spatial marking lies in the fact that the locksmith has not only to mark the individual surfaces of the part located in different planes and at different angles to each other, but also to link the marking of these surfaces to each other. For drawing marks and punching during marking, scribes, thickness gauges and center punch are used. Marking marks are applied to the surface of the part with a scribe with a hardened and sharply sharpened end. When drawing marks, the scribe should have a double slope: one. to the side of the ruler and the other. in the direction of movement of the scribe. The risk should only be carried out once; it should be as thin as possible. A gum, or scribe on a tripod, is used for drawing horizontal and vertical marks, as well as for checking workpieces installed on a marking plate on cubes or other devices.. indicating the marking risks, their intersections and the centers of the circles of the marked workpieces and parts. The center punch is carried out so that the marking marks are clearly visible. The center punch is taken with three fingers of the left hand and, with a sharp end inclined away from you, is pressed to the point marked at the risk so that the center point coincides with the middle of the marks. Before hitting with a hammer, the center punch is placed in a vertical position, and then it is fixed by resting the finger on the part and a light blow is applied to the center punch with a hammer weighing 50. 100 g. Marking compasses are used to mark circles and arcs, dividing circles and segments into parts and other geometric constructions when marking blanks. They are also used to transfer dimensions from a measuring ruler to a workpiece.
Give a sketch of the part to be marked:
What tool was used: scribe, hammer, marking compass, vernier caliper.
Cutting is called a locksmith operation, in which with the help of a cutting (chisel, cross-cutter, etc.) and percussion (metalwork hammer) tool, excess metal layers are removed from the surface of the workpiece (part) or the workpiece is cut into pieces.
Depending on the purpose of the workpiece being processed, the felling can be fine or rough. In the first case, a layer of metal with a thickness of 0.5 to 1 mm is removed with a chisel in one working stroke, in the second. from 1.5 to 2mm.
The processing accuracy achieved during felling is 0.4. 1mm. When cutting, cutting is carried out. the process of removing an excess metal layer in the form of chips from a workpiece (part) being processed by a cutting tool. The cutting part (blade) is a wedge (chisel, cutter) or several wedges (hacksaw blade, tap, die, cutter, file).
Chisel. This is the simplest cutting tool in which the wedge shape is especially pronounced. The sharper the wedge, that is, the smaller the angle formed by its sides, the less effort will be required to deepen it into the material. On the workpiece, a distinction is made between the machined and machined surfaces, as well as the cutting surface. The processed surface is the surface from which the layer of material will be removed, and the processed one. the surface from which the chips are removed. The surface on which the chips come off during cutting is called the front, and the opposite is the back.
Cutting tools. A chisel is a steel rod made of tool carbon or alloy steel (U7A, U8A, 7HF, 8HF). The chisel is made in lengths of 100, 125, 160, 200 mm, the width of the working part is 5, 10, 16 and 20 mm, respectively. The working part of the chisel at a length of 0.3. 0.5 is quenched and tempered. The degree of hardening of the chisel can be determined with an old file, which is carried out over the hardened part.
A cross cutter differs from a chisel by a narrower cutting edge and is intended for cutting narrow grooves, keyways, etc. For cutting profile grooves. semicircular, dihedral and others. special crosscutters are used, called grooves.
Grooves are made of U8A steel with a length of 80, 100, 120, 150, 200, 300 and 350 mm with a radius of curvature of 1; 1.5; 2; 2.5 and 3 mm. Tool sharpening on the machine by hand. Chisels and crosscutters are sharpened on a sharpening machine. Before sharpening the tool, the tool is placed as close as possible to the grinding wheel. The gap between the hand-hand and the grinding wheel should be no more than 2.3 mm so that the sharpened tool cannot get between the wheel and the hand-hand. Checking the sharpening angle of the tool. After sharpening the chisel or cross-cutter, the burrs are removed from the cutting edges. The angle of sharpening is checked with a template, which is a plate with angular notches of 70, 60, 45 and 35 degrees.
Locksmith’s hammer. it is a tool for working with various locksmith tools. Locksmith’s hammers with a round striker are made of six numbers: No. 1 (200 g) is used in marking and editing; No. 2 (400 g), No. 3 (500 g) and No. 4 (600 g). for locksmith work; No. 5 (800 g) and No. 6 (1000 g) are rarely used. Locksmith hammers with a square buoy are manufactured in eight numbers: No. 1 (50 g), No. 2 (100)
Give a sketch of the part:
What tool was used: Locksmith hammer, chisel.
T.B. The tool must be free of defects (cracks or chips). the hammer must not be oiled.
Cutting is the separation of parts (blanks) from bar or sheet metal. Cutting is performed with or without chip removal.
The essence of the scissor cutting process is the separation of parts of the metal under the action of a pair of cutting knives. The sheet to be cut is placed between the upper and lower knives. The upper knife, going down, presses on the metal and cuts it. Knives are made of U7, U8 steels; the side surfaces of the blades are hardened to HRCэ52. 58, ground and sharpened.
Cutting with hand scissors
Ordinary hand shears are used for cutting steel sheets with a thickness of 0.5. 1mm and non-ferrous metal sheets up to 1.5mm thick. Manual shears are made with straight and curved cutting blades.
According to the location of the cutting edge, the scissors blades are divided into right-hand ones (the bevel on each part of the cutting half is on the right side); left. (the bevel on each part of the cutting half is on the left side). The length of the scissors is 200, 250, 320, 360 and 400mm, and the length of the cutting part (from the sharp ends to the hinge). respectively 55.65, 70.82, 90.105, 100.120 and 110.130mm. Well-sharpened and well-adjusted scissors should cut the paper.
Chair scissors differ from ordinary scissors in large sizes and are used when cutting sheet metal up to 3mm thick. Chair scissors are not productive, they require significant efforts during work, therefore they are not used for cutting large batches of sheet metal.
Hand-held small-sized power shears are used for cutting sheet steel up to 2.5 mm thick and bars up to 8 mm in diameter. Scissor knives. removable and attached to levers with blind rivets. These knives are interchangeable and fit into the disc slot. For cutting bolts (studs) in the bushings of one of the discs there is a thread (several threads), which protects the thread of the bolts during cutting from crushing.
Lever shears are used for cutting sheet steel up to 4mm thick, aluminum and brass. 6mm. The upper articulated knife is operated by a lever. The lower knife is fixed. Knives are made of U8 steel and hardened to HRCe52 hardness. 60. The angles of sharpening of the cutting edges are equal to 5. 85 degrees. Before work, check the presence of grease on the rubbing surfaces, the smoothness of the lever stroke, the absence of a gap between the cutting edges.
The flywheel shears are widely used for cutting 1.5 sheet metal. 2.5 mm with a tensile strength of 450.500 MPa (steel, duralumin, etc.). These scissors cut metal of considerable length.
Shears with inclined knives (guillotine) allow cutting sheet metal up to 32mm thick, sheets with dimensions 1000. 32000mm, less often. strip products, as well as sheet non-metallic materials.
Hand hacksaw (saw) a tool designed for cutting thick sheets of strip, round and profile metal, as well as for cutting slots, grooves, trimming and cutting out workpieces along the contour and other works.
A hacksaw blade is a thin and narrow steel plate with two holes and teeth on one or both edges. The canvases are made of U10A and Kh6VF steels, their hardness is HRCe61. 64. Depending on the purpose, hacksaw blades are divided into manual and machine.
The size (length) of a hand-held hacksaw blade is determined by the distance between the centers of the holes for the pins, the length of the hand-saw blade is L = 250. 300mm, height b = 13 and 16mm, thickness h = 0.65
For cutting metals of various hardness, the angles of the teeth of the hacksaw blade are performed as follows: the rake angle is 0. 12 degrees; and the rear angle of the teeth is 35.40 degrees; the taper angle is 43.60 degrees.
For cutting harder materials, blades are used, in which the angle of sharpening of the teeth is greater, for cutting soft materials, the angle of sharpening is less. Blades with a large taper angle are more wear-resistant.
Setting the teeth of the hacksaw blade. When cutting with a hand hacksaw, at least two should participate (cut metal at the same time). three teeth. To avoid jamming (jamming) of the hacksaw blade in the metal, the teeth are set apart so that the width of the cut made with the hacksaw is much greater than the thickness of the blade. over, it will make the job much easier. The distribution of the hacksaw blade should end at a distance of no more than 30 mm from the end.
Preparing to work with a hacksaw. Before working with a hacksaw, the material to be cut is firmly fixed in a vice (the level of fastening must correspond to the height of the worker). For long cuts, hacksaw blades with a large tooth pitch are used, and for short ones. with small.
The hacksaw blade is installed in the slot of the head so that the teeth are directed away from the handle, and not towards it. In this case, the end of the web is first inserted into the fixed head and fixed with a pin, then the second end of the web is inserted into the slot of the movable pin and also secured with a pin. At the same time, due to the fear of rupture of the blade, the hacksaw is kept away from the face. The degree of tension of the web is checked by lightly pressing it with your finger from the side; if the blade does not flex, the tension is sufficient.
When cutting with a hand hacksaw, they stand in front of the vice straight, freely and steadily, half a turn in relation to the jaws of the vice or the axis of the workpiece being processed. The feet are placed so that they form an angle of 60.70 degrees with a certain distance between the heels.
Hand position (grip). The handle is wrapped with four fingers of the right hand so that it rests on the palm; the thumb is placed on top along the handle. The fingers of the right hand grasp the nut and the movable head of the hacksaw.
When cutting with a hacksaw, as well as when filing, strict coordination of efforts (balancing) must be observed, which consists in the correct increase in hand pressure.
There are two strokes during the cutting process. worker, when the hacksaw moves forward from the worker, and idle, when to the worker. When idling, the hacksaw is not pressed, as a result of which the teeth only slide, and during the working stroke, light pressure is created with both hands so that the hacksaw moves in a straight line.
When working with a hacksaw, the following rules must be followed:
Cut short workpieces on the shortest side; when cutting rolled corner, tee and channel profiles, it is better to change the position of the workpiece than to cut along the narrow side; the entire hacksaw blade must be involved in the work; do not allow the blade to heat up when cutting; to reduce the friction of the blade against the walls in the cut of the workpiece, periodically lubricate the blade with mineral oil or graphite grease, especially when cutting viscous metals; cut brass and bronze only with new blades, since even slightly worn teeth do not cut, but slide; in case of breakage or chipping of at least one tooth, immediately stop work, remove the remnants of the broken tooth from the cut, replace the blade with a new one or grind two off on the machine. three adjacent teeth; after that you can continue working.
Hacksaw cutting round, square, strip and sheet metal.
Round metal of small sections is cut with hand hacksaws, and workpieces of large diameters. on cutting machines, powered hacksaws, circular saws, etc. Previously, the blade is lubricated with oil using a brush.
For the correct start of the cut on an unmarked workpiece, at the place of the cut, place the thumb of the left hand with a fingernail and put the blade of the hacksaw close to the nail. The hacksaw is held only with the right hand. The index finger of this hand is pulled along the side of the handle, which ensures a stable position of the workpiece during cutting.
The workpiece is fixed in a vice and a shallow cut is made in the place of the future cut with a triangular file for a better direction of the hacksaw. Then the workpiece is cut with the hacksaw in a horizontal position. For very deep cuts, the left hand is rearranged, taking the top of the frame.
It is more rational to cut strip metal not along the wide, but along the narrow side.
Cutting with a hacksaw with a turn of the blade is carried out with long (high) or deep cuts, when it is not possible to bring the cut to the end from. because the hacksaw frame rests against the end of the workpiece and interferes with further sawing. In this case, you can change the position of the workpiece and, cutting into it from the other end, finish cutting. Can be cut with a hacksaw, in which the blade is rearranged 90 degrees. This method is used to cut metal in parts with closed contours.
Billets, parts made of thin sheet metal are clamped between wooden blocks one or more pieces and cut together with the bars.
To cut a shaped window (hole) in metal (sheet), drill or cut a hole with a diameter equal to the width of the blade of a hacksaw or jigsaw.
Large slots are cut with ordinary hacksaws with one or two (depending on the width of the slots) blades connected together.
Cutting pipes with a hacksaw and pipe cutter
Before cutting, the pipe is marked according to a template made of sheet metal bent along the pipe. The template is applied to the cut site and marking risks are applied along the pipe circumference with a scraper. Pipes are cut with hacksaws and pipe cutters.
Cutting with a hacksaw. The pipe is clamped in a parallel vise in a horizontal position and cut at the risk. When cutting the pipe, the hacksaw is held horizontally, and as the blade is cut into the pipe, it is slightly tilted towards itself. If the hacksaw curls away from the marking risks, the pipe is turned around the axis and cut at the risk in a new place
Give a sketch of the part:
What tool was used: Hacksaw for metal, locksmith files, vernier caliper ШЦ-I, ruler, square, radius gauge, hammer, pliers.
Sawing is the processing of holes in order to give them the desired shape. Round holes are processed with round and semicircular files, triangular. triangular, hacksaw and rhombic files, square. square files.
Sawing a square hole knob in the workpiece. First, mark the square, and in it. hole, then drill the hole with a drill, the diameter of which is 0.5 mm less than the side of the square.
Further processing of the sides is carried out until the square head easily but tightly fits into the hole.
Sawing a triangular hole in the workpiece. Mark out the outline of the triangle, and in it. hole and drill it with a drill, without touching the marking lines of the triangle. The gap between the sides of the triangle and the liners when checking with a feeler gauge should be no more than 0.05mm.
Give a sketch of the part:
Tool used: Round file.
Bending and straightening of metal.
Flexible. This is a method of metal working by pressure, in which a workpiece or part of it is given a curved shape. Locksmith’s bending is performed with hammers (preferably with soft strikers) in a vice, on a plate or using special devices. Thin sheet metal is bent with mallets, wire products up to 3mm in diameter. pliers or round nose pliers. Only plastic material is bendable.
When bending parts at right angles without rounding on the inside, the bend allowance is taken from 0.5 to 0.8 of the material thickness.
Bending of sheet and strip metal parts.
The bending of a rectangular staple made of strip steel is performed in the following order: the length of the blank is determined by adding the length of the sides of the staple with an allowance for one bend equal to 0.5 of the strip thickness, i.e. L = 17.5115120115117.5 = 89mm; mark the length with an additional allowance for processing the ends of 1 mm per side and chop off the workpiece with a chisel; straighten the cut blank on the plate; sawn to size according to the drawing; inflict bending risks; clamp the workpiece in a vice between the squares. with mouthpieces at the level of risks and hammer blows, bend the end of the bracket (first bend); rearrange the workpiece in a vice, clamping it between the square and the bar. a mandrel longer than the end of the staple; fold the second end, making a second fold; remove the workpiece and take out the bar. mandrel; mark the length of the legs at the bent ends; put the second square on the vice and, putting the same bar inside the bracket. the mandrel, but in its other position, clamp the bracket in a vice at the level of the marks; unbend the first and second legs, make the fourth and fifth folds of the first and second legs; check and straighten the fourth and fifth bends along the square; remove burrs on the edges of the staple and saw off the ends of the legs to size.
The bending of a double square in a vice is carried out after marking, cutting the workpiece, straightening on a plate and filing in width to a given size. At the end of bending, the ends of the square are sawn to size and deburred from sharp edges.
The collar is flexible. After calculating the length of the workpiece and marking it at the bend points, the mandrel is clamped in a vice in a vertical position. The diameter of the mandrel must be equal to the diameter of the collar hole. The final shaping of the clamp is carried out on the same mandrel with a hammer, and then on a straightening plate.
Bending the ear with round-nose pliers. An eyelet with a thin wire rod is made using round-nose pliers. The length of the workpiece must be 10.15mm longer than required by the drawing. After the end of the work, the excess end is removed with nippers.
Sleeve bending. Suppose it is required to bend a cylindrical sleeve from strip steel on round mandrels. First, the length of the workpiece is determined. If the outer diameter of the sleeve is 20mm, and the inner. 16mm, then the average diameter will be 18mm. Then the total length of the workpiece is determined by the formula L = 3.14×18 = 56.5mm.
Editing and straightening.
Straightening and straightening are operations for straightening metal, blanks and parts with dents, bulging, waviness, warping, curvature, etc. Straightening and straightening have the same purpose, but differ in the methods of execution and the tools and devices used.
The metal is straightened both in the cold and in the hot state. The choice of method depends on the deflection, dimensions and material of the product. The straightening is done manually on a straightening plate or anvil. machine on rollers or presses.
Straightening heads are used for straightening (straightening) hardened parts; they are made of steel and hardened.
For straightening, hammers with a round smooth polished striker are used.
For straightening hardened parts (straightening), hammers with a radius striker are used; the hammer body is made of U10 steel; the weight of the hammer is 400.500 g.
Hammers with push-in strikers made of soft metals are used for straightening finished parts.
Ironers (wood or metal bars) are used when straightening thin sheet and strip metal.
The curvature of the parts is checked by eye or by the gap between the plate and the part.
When editing, it is important to choose the right places to hit. Straightening is performed on an anvil, a straightening plate or reliable pads, excluding the possibility of parts slipping from them upon impact.
Strip metal is straightened in the following order.
The strip is placed on a regular slab so that it lies with the bulge upward, contacting the slab at two points. The blows are applied to the convex parts, adjusting their strength depending on the thickness of the strip and the magnitude of the curvature; the greater the curvature and the thicker the strip, the stronger the blows should be. The result of straightening (straightness of the workpiece) is checked by eye, and more precisely. on a marking plate along the lumen or by overlaying a ruler on a strip.
Bar straightening. After checking by eye on the convex side, the boundaries of the bends are marked with chalk. Then the bar is laid on a slab or anvil so that the curved part is convex upwards and blows with a hammer.
Sheet metal editing is more difficult than previous operations.
When straightening workpieces with bulges, warped areas are identified, and it is established where the metal bulges more. Editing begins from the edge closest to the bulge, along which one row of hammer blows is applied within the limits indicated by the blackened circles. Then hitting the second edge.
After that, a second row of blows is applied along the first edge and move again to the second edge and so on until they gradually approach the bulge.
Thin sheets are ruled with light wooden hammers. mallets, copper, brass or lead hammers, and very thin sheets are laid on a flat plate and smoothed with metal or wooden bars.
Straightening (straightening) of hardened parts. Steel parts sometimes warp after hardening. Straightening curved parts after hardening is called straightening. The straightening accuracy can be 0.01. 0.05mm.
Depending on the nature of the straightening, hammers with a hardened striker or special straightening hammers with a rounded side of the striker are used.
Products with a thickness of at least 5 mm, if they are hardened not through and through, but only to a depth of 1.2 mm, have a viscous core, therefore they are straightened relatively easily; they need to be straightened by striking bulging places. In the case of warpage of the product along the plane and along the narrow edge, straightening is performed separately. first along the plane, and then along the edge.
Straightening of short bar material is performed on prisms, straightening plates or simple shims. Straightness is checked by eye or by the gap between the bar and the plate.
Shafts (up to 30 mm in diameter) are straightened on hand presses using a prism.
Straightening by work hardening is carried out after laying the curved shaft on a flat plate with the bulge downward, inflicting frequent and light blows on the surface of the shaft with a small hammer, after the appearance of the hardened layer on the surface, the gap between the shaft and the plate disappears. editing is stopped.
Mainly, enterprises use machine straightening on straightening rollers, presses and special devices.
Bending rolls are available as manual or powered. On manual and driven three-roll bending rolls, workpieces are straightened and curved along the radius, with bulges and dents on the surface.
The three-roll plate bending machine has rolls located one above the other, which are adjusted depending on the thickness of the workpiece, moving away from each other or approaching. The workpiece is placed between the two front rolls and, turning the handle clockwise, is passed between the rolls until the bulges and dents are completely eliminated.
Straightening of shafts and angle steel on screw presses, is used in cases where straightening with a hammer does not provide the desired result.
Straightening of angle steel has some peculiarities. The deformed corner is installed in a prism on the press table, a hardened steel roller is installed between the corner shelves. When pressed with a press screw, the roller gives the corner an appropriate shape. Sheets, strips and ribbons are straightened on sheet-straightening machines, horizontal correctly. stretching machines and pneumatic hammers.
Warped welded joints are cold straightened.
By hand with wooden and steel hammers on slabs, anvils, etc. Cold straightening is done with extreme care.
Safety. When straightening and straightening metals, it is necessary to comply with the following safety requirements: work only with a serviceable tool (correctly fitted hammers, no cracks on the handles and spalling on hammers);
Sawing is an operation for the processing of metals and other materials by removing a small layer with files manually or on filing machines.
Files are used to process planes, curved surfaces, grooves, grooves, holes of any shape, surfaces located at different angles, etc. The filing allowances are kept small. from 0.5 to 0.25mm. The filing precision is 0.2. 0.05mm (in some cases. Up to 0.001mm).
A file is a steel bar of a certain profile and length, on the surface of which there are notches (cuts) that form depressions and sharpened teeth (teeth) that have a wedge-shaped cross-section. Files are made of steel U10A, U13A, ShKh15, 13X, after incision they are heat treated.
Files are subdivided according to the size of the notch, its shape, length and shape of the bar.
Types and basic elements of notches. Notches on the surface of the file form teeth that remove chips from the material being processed.
Single cut files can cut wide chips equal to the length of the entire cut. They are used for filing soft metals and alloys with low cutting resistance, as well as non-metallic materials. A single cut is applied at an angle of 25 degrees to the file axis.
Double (cross) cut files are used for filing steel, cast iron and other hard materials with high cutting resistance.
Files with a rasp (dot) cut (rasps) are used for processing very soft metals and non-metallic materials. leather, rubber, etc.
The rasp (point) notch is obtained by pressing the metal with special chisels.
Arc cut files are used when processing soft metals.
An arc cut is obtained by milling; it has large tooth spaces and an arched shape for high productivity and improved surface quality.
According to their purpose, files are divided into the following groups: general purpose; special purpose; needles; rasps; machine.
General purpose files are intended for general metalwork. According to the number n of notches (teeth) per 10mm of length, files are divided into six classes, and the notches are numbered 0, 1, 2, 3, 4, and 5;
the first class with a notch number 0 and 1 (n = 4. 12), called fights;
the second class with a notch number 2 and 3 (n = 13. 24) are called personal;
third, fourth and fifth grade with
notches No. 4 and 5 (n = 24.28), called velvet.
Files are divided into the following types:
B. flat sharp-nosed files are used for filing external or internal flat surfaces;
B. square files are used for sawing square, rectangular and polygonal holes;
D. triangular files are used for filing sharp angles equal to 60 degrees or more, both on the outside of the part and in grooves, holes and grooves;
E. round files are used for sawing round or oval holes and small radius concave surfaces;
E. semicircular files with a segmented section are used for processing concave curved surfaces of significant radius and large holes (convex side);
J. rhombic files are used for filing gear wheels, discs, and asterisks;
Z. hacksaw files are used for filing inner corners, wedge-shaped grooves, narrow grooves, planes in triangular, square and rectangular holes.
Flat, square, triangular, semicircular, rhombic and hacksaw files are made with serrated and cut teeth.
Rhombic and hacksaw files are made only with cuts No. 2, 3, 4 and 5, respectively, length 100.250mm and 100.315mm.
Special-purpose files for processing non-ferrous alloys, in contrast to general-purpose plumbing files, have other, more rational for a given alloy, incline angles of notches and a deeper and sharper notch, which ensures high productivity and durability of files.
Files for processing bronze, brass and duralumin have a double cut. the upper one is made at angles of 45, 30 and 50 degrees, and the lower one. respectively at angles of 60, 85 and 60 degrees. Files are marked with the letters CM on the shank. And also there are for processing products from light alloys and non-metallic materials, tared and diamond files.
Needle files. these are small files used for curving, engraving, jewelry work, as well as for cleaning in hard-to-reach places (holes, corners, short sections of a profile, etc.).
Needle files are made from steel U13 or U13A (U12 or U12A is allowed). File lengths are set to 80, 120 and 160mm.
Depending on the number of notches per 10mm of length, the files are divided into five types. Nos. 1, 2, 3, 4 and 5. The files have on the handle engraved notch numbers: No. 1. 20. 40; No. 2. 28.56; Nos. 3, 4 and 5.40.112 notches per 10mm length.
Diamond needle files are used for processing carbide materials, various types of ceramics, glass, as well as for finishing carbide cutting tools. When processing with files, surfaces with a roughness of Ra 0.32 are obtained. 0.16.
Rasps are intended for processing soft metals (lead, tin, copper, etc.) and non-metallic materials (leather, rubber, wood, plastics), when ordinary files are not suitable. Depending on the profile, the rasps are blunt and pointed, as well as round and semicircular with notches No. 1 and 2 with a length of 250.350 mm.
The filing of the outer flat surfaces begins with checking the machining allowance, which could ensure the manufacture of the part in accordance with the drawing. When filing flat surfaces, use flat files. fierce and personal. Sawing is carried out with cross strokes. The parallelism of the sides is checked with a caliper, and the quality of filing. a straight edge in various positions (along, across, diagonally).
Straight rulers are used to check the straightness of the sawn surfaces against light and paint. When checking the straightness in the light, a curved ruler is placed on the controlled surface and, according to the size of the light slit, it is determined in which places there are irregularities.
Sawing the surfaces of the square located at right angles is associated with the fit of the inner corner and is associated with some difficulties.
Sawing the end of the rod into a square begin with filing the face, check the size with a caliper.
Safety. When filing work, the following safety requirements must be observed:
when filing workpieces with sharp edges, do not squeeze the fingers of the left hand under the file during the return stroke;
the chips formed during the filing process must be swept from the workbench with a hair brush; it is strictly forbidden to dump the shavings with bare hands, blow them away or remove them with compressed air;
when working, use only files with firmly attached handles; do not work with files without handles or files with cracked, split handles.
Give a sketch of the part:
What tool was used: Twist drills, vernier calipers, bench files, metric ruler, hammer, drilling machine, square, radius gauge, center punch, chisel, hacksaw.
TB The file handle must be firmly seated.
Assembly and disassembly operations.
General rules for disassembly and assembly. Any unit or unit of the car will work reliably only if it is correctly assembled, in compliance with all the necessary conditions and requirements. First of all, the parts must be completely clean during assembly. Before staging, be sure to carefully examine the details. If there are risks, burrs, scratches on their mating surfaces, they should be cleaned with a small (velvet) file or a fine-grained bar. Especially carefully you need to clean the threads, if necessary, they should be “driven out” with a tap or a scraper. The bolt or nut must be loosely screwed without jamming from the corresponding part. However, the latter does not apply to self-locking threaded connections used in some parts of the car.
All parts must be lubricated with grease of the type that is used in this unit before assembly. All threads must be lubricated, preferably with grease (grease, Litol-24). If the threaded hole goes into the cavity of some unit and oil can seep through the thread, then in this case the thread should be lubricated with a sealant or glue (the use of adhesives will be discussed below).
It should be borne in mind that some parts of the car are not interchangeable. During production, they are processed on machines assembled together with the mating part. For example, a hole in the bottom (crank) end of the connecting rod is bored after the head cover is in place and bolted with proper torque. It is clear that such parts during disassembly and assembly cannot be interchanged, turned over the other side, etc. The group of non-interchangeable parts includes: crankshaft main bearing caps, connecting rod caps, differential bearing caps, clutch housing. Usually, special marks are put on these parts at the factory so that they cannot be confused. If there are no such marks, then during disassembly they need to be applied with paint or punching.
Other parts of the car are fundamentally interchangeable, but since each of them has already been worked in with the mating part, then during assembly it should also be put in the same place, otherwise increased wear is inevitable in the future. Such parts include, for example, pistons with connecting rods, valves, tappets and others.
This implies a general important rule: when assembling, all parts must be put in their original places, for which they should be marked during disassembly.
Bolts and nuts securing components and assemblies should be tightened evenly, in two or three steps and in the sequence recommended by the instructions. Be sure to tighten the most critical bolts with a torque wrench with the required effort (moment). These primarily include the nuts or bolts that secure the cylinder head. If you tighten these bolts, for example, more than it should be, or in a different order than it should be, then the block and the head are slightly deformed, the cylinders lose their correct geometric shape, which leads to increased wear of the pistons and cylinders. It is also possible that a coolant leak occurs, a head gasket burns out, etc. If the tightening is weak, a reliable seal will not be ensured.
The bolts of the connecting rod caps and the main bearings of the crankshaft, as well as bolts and nuts in some other joints of the car, must also be tightened with a certain torque.
Wrenches must always match the size of the bolts (nuts). If the edges of the bolt (nuts) are slightly damaged (crumpled), they need to be corrected with a file.
Pay attention also to match the length of the wrench to the size of the nut. The fact is that if the key is too large, then the thread can be easily ripped off. Therefore, it is not recommended to lengthen the wrenches in any way or use a long adjustable wrench to work with small nuts.
It must be said that excessive tightening of threaded connections up to thread breaking is a common “disease” of insufficiently experienced motorists. To avoid this, it is recommended, while tightening small, 6.8 mm, bolts, to hold and turn the wrench not with the whole hand, but only with one or two fingers, thereby limiting the applied force. The casings of ball and roller bearings are pressed onto the shaft (or into the sleeve) using special mandrels by press force or light hammer blows. Mandrels must be made in such a way that the pressing force is not transmitted through the balls.
The following techniques are recommended for loosening very tight bolts and nuts. First of all try to slide the bolt or nut slightly in the direction of tightening. It happens that after that they turn away without much difficulty. Next, try to knock on the nut with a hammer. You can put a tampon abundantly moistened with kerosene on the end of the bolt for several hours (gasoline is not good, as it evaporates quickly). This method usually leads to success. In extreme cases, heat the nut with a large soldering iron and let it cool down, repeating this operation 2. 3 times.
The studs are screwed into the threaded socket and turned out with a special wrench with an eccentric clamp. In the absence of a key, two nuts are screwed onto the stud, tightened relative to each other and then use a regular wrench. In some parts of the car, fasteners with a left-hand thread are used (for example, nuts for fastening the front wheel hub of the Zhiguli, nuts of the steering rods and the plug of the steering box of the Muscovites). On the edges of such nuts, to distinguish them from ordinary ones, grooves (notches) are made.
Bolts for critical connections are made of high quality steel and heat treated. To distinguish these bolts have an “x” on the head. These bolts cannot be replaced with ordinary ones, especially the first ones that come to hand, since the necessary strength will not be provided. Such bolts are used, for example, for connecting flanges of universal joints and in the front suspension of a car.
Features of disassembly and assembly of some parts of the car. Cardan joints must not be disassembled and assembled by hammer blows, as this will inevitably disrupt the alignment of the holes in the forks, which will lead to accelerated wear of the bearings and trunnions of the cross.
As a press for disassembly and assembly, a fairly powerful table vise is used.
When assembling universal joints, bearings and locking rings, they should be placed in the same holes of the forks from which they were removed. The crosspiece and forks must also be installed in the same position relative to each other. Failure to comply with these requirements will cause imbalance in the driveline and, as a result, vibration and noise when driving. Therefore, before disassembling it, all parts should be marked with paint.
The ball pins of the steering linkages can be easily removed from their seats using a screw puller. In the absence of the latter, the operation becomes significantly more difficult. Hammering the threaded end of a finger usually does not work, and there is a risk of damaging the thread. The following technique is much more effective. Unscrew the nut and tap the socket on all sides with a hammer that holds the tapered end of the ball pin (you do not need to hit the finger itself). After a few strokes, the finger will loosen and can be removed. When assembling, lubricate the seating surface of the pin with oil: this will facilitate subsequent disassembly.
The nuts of the step-ladders of the springs (Moskvich, Volga cars) should be tightened with a torque wrench with a certain moment specified in the manufacturer’s instructions for the car. If the tightening is weak, the bridge may shift when hitting a road obstacle. If the tightening is too strong, this will cause deformation of the rear axle beam and, as a result, incorrect (skewed) operation of the axle shaft bearings. As a result, the bearings will fail prematurely, and the axle shafts may also break. The nuts of the ladders must be tightened one by one, and the final tightening must be done when the springs are loaded. At the same time, load the trunk of the car so that the springs are fully straightened. Failure to do so will result in insufficient tightening of the ladder nuts when the vehicle is under operational load.
Rubber bushings and rubber-metal hinges (silent blocks) of the front and rear suspensions of the car are designed so that the swing of the suspension arms occurs only due to the deformation of the rubber. These bushings must not rotate in the cages or on the pins. To ensure that the rubber bushings twist approximately equally in both directions during operation, the fastening nuts should only be tightened completely when the suspension is loaded with the weight of the vehicle (that is, the unloaded vehicle is on its wheels). Due to the peculiarities of its design, the Zhiguli car should also be fully loaded (4 adults and 40 kg of luggage, that is, only 320 kg).
When replacing the rubber bushings of the springs, for better adhesion, it is recommended to dip them in gasoline for 1 min and, without letting dry, quickly mount them into the hinge.
If you removed the steering column, then it is necessary to install it back and fix it in the following order. First you need to attach (without tightening) the bolts securing the steering box housing to the frame side member. Then pull the column to the car dashboard, secure it with a bracket and only then finally tighten the crankcase mounting bolts. If you do not follow the specified sequence, but first tighten the bolts securing the crankcase to the frame, then when tightening the bolts of the upper steering column support (to the instrument panel), the column itself and the steering shaft may bend slightly, as a result of which the steering wheel will rotate tightly. In addition, this will lead to increased wear of the steering gear bearings and may even cause damage to the steering shaft. I must say that almost all cases of shaft breakdowns encountered in operation are caused precisely by improper assembly.
When performing maintenance and repair work on brakes, remember that cuffs, O-rings, flexible hoses are made of rubber that is not resistant to oil products. Even small amounts of gasoline or oil that enter the brake system (for example, from dirty dishes or even from hands) can damage the brakes. Rinse the lines and parts of the brake system only with fresh brake fluid, observing the necessary cleanliness, and wipe with a clean cloth that does not leave lint. When replacing the brake hoses of the front wheels, make sure that they do not touch the tires when the steering wheel is turned the most to the left and right.
The engine crankshaft is balanced at the factory with the flywheel and clutch. Therefore, install the removed clutch mechanism back on the flywheel in accordance with the existing marks. Otherwise, an imbalance of the crankshaft, strong shaking of the engine and various malfunctions in its operation may occur. The cylinder head bolts or nuts should be tightened in the sequence recommended by the manufacturer only on a cold engine. If this operation is performed on a warm engine, the tightening will be insufficient after it has cooled down. The reason for this is the different thermal expansion of the steel bolts and the aluminum head.
Tighten the spark plugs only on a cold engine, as a spark plug wrapped in a hot head is then difficult to unscrew. Do not overtighten the plugs; at the same time, the gasket is excessively wrinkled, and its sealing effect becomes worse.
The wing nuts used on some vehicles to secure the battery and air cleaner are designed to be tightened by hand only. When trying to tighten them tighter, for example with pliers, it is easy to damage the battery case or bend the air cleaner cover.
Application of adhesives. In modern mechanical engineering, synthetic adhesives are widely used to simplify and facilitate assembly operations, as well as to achieve tightness at the joints between parts and greater reliability of threaded connections. When repairing a car or performing maintenance on it, you may in some cases use glue.
All mounting studs can be “glue-down” by lubricating the threaded end of the stud before screwing into the socket. Due to this, the overall strength of the connection increases, a reliable locking of the stud and complete tightness of the thread is achieved. The latter circumstance is important in cases where the hole for the pin goes into the oil cavity (for example, in the UMZ-412 engine, the holes for the studs of the intake pipe attachment exit into the valve box). The most reliable glue for these purposes is epoxy; you can also use BF-2 glue or bakelite varnish. Fastening bolts in various parts of the car can also be “put on glue” if you need reliable protection against self-loosening and tightness of the thread. The adhesives are used the same as for the studs, however, if the assembly must be disassembled periodically, then it is better to use BF-2 glue, since the epoxy is quite strong and the bolt will then be difficult to unscrew. It is advisable to “put on glue”, for example, the bolts of the rear axle gearbox, Gaskets and joints between parts in those joints of the car that are never disassembled during operation or are very rarely disassembled, it is also recommended to “put on glue”, due to which complete tightness of the joint. This applies, for example, to the gaskets for the engine oil sump, the rear axle reducer flange, the cylinder block side covers, the gas intake tube flanges and the fuel level sensor. When the adhesive joint is subsequently disassembled, the gasket will of course be destroyed. Keep in mind that the surfaces of the parts and gaskets must be cleaned and degreased before applying the adhesive, otherwise the connection will not be reliable. To do this, the surfaces to be glued should be washed with gasoline, wiped with a clean cloth soaked in acetone, and then dried.
Car repair and maintenance work can be successful only with the necessary tools and devices. The toolkit that comes with your vehicle is designed primarily for minor troubleshooting on the road. Therefore, a motorist who wants to independently carry out more or less complex maintenance and repair operations on a car should acquire some more devices and tools.
Fitting and assembly tools. It is desirable to have open wrenches in a full range, and it is better in two copies. Combination and adjustable wrenches, special pliers for nuts are not recommended, as they are inconvenient to work, usually do not allow creating a lot of effort when tightening or unscrewing a nut or bolt and damage the named parts
It is imperative to purchase a set of socket wrenches (heads) with a knob and an extension cord. The heads are 6 and 12-sided. The latter allow you to rearrange the key to its original position after turning a small angle and thus facilitate work in confined spaces. In addition, they securely hold the head of the bolt or nut, even if its edges are slightly damaged.
Almost every car has such inconvenient bolts or nuts on which it is impossible to put the socket wrench head on: neighboring, closely spaced parts interfere. Heads designed for such bolts or nuts are recommended to be turned from the outside on a lathe to slightly reduce their diameter.
Critical threaded connections must be tightened with a certain force (torque). Therefore, it is highly desirable for a motorist to have a torque wrench. These keys are commercially available. There should be several screwdrivers, with different blade widths and different lengths. Tightening tightly tightened screws requires a particularly powerful, durable screwdriver. It is best to make them in the form of a set of interchangeable blades of various widths that could be inserted into the brace cartridge.
The blade of the screwdriver must be properly sharpened. An incorrectly sharpened screwdriver makes it impossible to apply the necessary force to the screw and spoils its head.
The center punch is a hard steel rod with a pointed end. It is used to apply recessed dots on metals and plastics. They mark the places of drilling, apply various marks, etc. A good center punch can be made from a fragment of a drill or an old tap, sharpening them on a grinder.
The set of tools should include at least two hammers. one weighing 200 g, the second heavier, 500 grams. When assembling and disassembling car mechanisms, in many cases, you need pins. cylindrical rods made of soft metal (brass, duralumin). It is desirable to have punches with a diameter of 6. 8 and 14. 16 mm, a length of 150.200 mm. Punches are essential for making correct round holes in spacers made of paper, cardboard, rubber and other materials. The punch is a metal tube with a pointed end. The blank material is placed on the end surface of a wooden block, a punch is installed and a hole is cut through with a strong hammer blow. A threading tool is also required, tools. taps and dies. In automotive practice, they are most often used for driving (cleaning) threads before assembly. First of all, a motorist needs taps and taps of the following sizes: М5Х0.8; M6X1; M8X1; M8X1.25; M10X1; M10X1.25; М10Х1,5.
Special tools and devices greatly facilitate the work of car repair and maintenance. It is much more convenient to tighten the clamps on rubber hoses with a special wrench than with pliers, as many people usually do. The key is a steel rod with a diameter of S. 4 mm and a length of 50. 60 mm, the end of which 10 mm long is bent at an angle of 45 °. An excellent blank for such a key is a piece of a drill of suitable sizes. To remove the oil seal from the front wheel hub, it is recommended to make a special blade from a strip of steel. The blade is inserted with the curved end into the gap between the outer ring of the bearing and the oil seal and, tilting it with some effort in both directions, the latter is gradually pressed out.
Sometimes the threads in the spark plug hole are contaminated with carbon particles. It is best to clean it with a tap, but it is not easy to get such a tap with SPM14X1.25 thread. Therefore, a replacement tool can be made from an old candle with a long thread. Remove the insulator from the candle by knocking it out with a narrow chisel, sawing the threaded part with a hacksaw crosswise and slightly filing the thread to get four cutting edges, like a tap. Excellent Thread Cleaning Tool Ready.
For pressing out the bearing races, for extracting the ball pins of the steering drive from the seat and in many other cases, special pullers are required. Strippers can be purchased or made by yourself.
The basis of all types of cutting processes is turning, and the main means of metal processing is a turning tool.
To carry out the cutting process, it is necessary to have two movements. the main (working) movement and the feed movement.
The main movement when turning. this is the rotational movement of the workpiece being processed. The forward movement of the cutter in the longitudinal or transverse direction is the feed movement in turning. On some machines (for example, automatic lathes), the workpiece has feed movements.
Incisors are the simplest and most commonly used tools. The cutter consists of a head (working part) and a holder. The holder is used to fix the cutter in the machine support. Distinguish between passing, cutting, scoring, boring, threaded and shaped cutters. Through cutters (straight and bent) are used for turning external surfaces, chamfering. Scoring. for trimming the ends of the workpiece, threaded. for cutting external and internal threads, cutting. for cutting off the workpiece. Boring cutters are used for boring through and blind holes.
Distinguish between rough and finish turning. In rough turning, processing is carried out with the maximum permissible depth of cut and cutter feed according to the processing conditions. Finished turning produces parts with the final dimensions and surface of a high roughness class.
Milling cutter. multi-edge cutting tool, usually in the form of a disc with teeth around the circumference, with a rotary motion, designed for surface treatment.
Milling processing. a method of metal processing in which the main motion is the rotation of the cutter, and the feed motion is the translational movement of the workpiece being processed in the longitudinal, transverse or vertical directions.
Milling is done with a cutting tool called a milling cutter. Cutting teeth can be located both on the cylindrical surface and on the end. Each cutter tooth is the simplest tool. a cutter. Cutters, as a rule. multi-flute tool, but sometimes single-flute cutters are used. The main types of cutters: disk, cylindrical, end, keyway, corner, end, slot (cut), shaped. Structurally divided into one-piece, with replaceable teeth and prefabricated.
On horizontal milling machines, the axis of rotation of the cutter is located horizontally, and on vertical milling machines. vertically, but can be rotated at an angle of /. 45 ° in the vertical plane.
Examples of work performed on horizontal milling machines: processing of rectangular and shaped grooves with disk cutters, processing of vertical surfaces with end mills. Vertical milling machines perform such work as processing horizontal surfaces with end mills, processing bevels and vertical surfaces, processing closed and open keyways with end mills.
Grinding is the process of cutting with abrasive wheels.
With circular and surface grinding, the main movement is always rotational; it is done with a tool (grinding wheel). With cylindrical grinding, the workpiece rotates, which ensures the circumferential feed. However, the circle in some cases does not cover the entire length of the workpiece, therefore, a longitudinal feed is also needed, which is performed by the workpiece or the circle. In surface grinding, the workpiece most often has a longitudinal feed, and a transverse one. circle or blank.
The abrasive grains in the wheel are randomly arranged and held together by the bonding material. A very large amount of thin chips is cut from the workpiece (up to 100 million per minute). Grinding wheels operate at very high cutting speeds: up to 30 m / s and more. With the help of grinding, finishing and finishing processing of parts is carried out with high precision. The cutting component of the abrasive tool is the grains of abrasive materials: aluminum oxide, silicon carbide, diamond, cubic boron nitride. The bond of abrasive material in the tool can be ceramic, bakelite, vulcanite, glyphthalic and polyvinyl formal.
An important characteristic of an abrasive tool is its hardness, i.e. resistance of the bond to the pulling out of abrasive grains from the surface of the tool under the influence of cutting forces. The harder the circle, the more force is needed to pull the grain out of the bond, but at the same time, the more the tool’s tendency to “salting” (clogging of pores with chips) especially when sanding viscous materials.
A process in which machining is performed with a single-edged tool that reciprocates. planing.
With this type of processing on planing machines, the main movement is imparted to the workpiece, and the feed movement. tool (cutter). When planing on cross-planing machines and processing blanks on slotting machines, the main movement is imparted to the tool (cutter), and the feed movement. workpiece or cutter.
For a more complete use of the power of the machine, multi-cutter planing is used.
High-performance finish planing is carried out with wide planing tools equipped with carbide-tipped plates: the process is carried out at high feed rates. up to 20 mm / dv. stroke and more. The rational cutting mode during planing is determined by the same method as for turning, taking into account the corresponding correction factors.
The main disadvantages of planing: the impact of the tool (cutter) at the beginning of each working stroke and the presence of an idle stroke, which reduces tool life and processing productivity.
Drilling is the formation of holes in a solid material by chip removal with a cutting tool. drill. Drilling is used to obtain holes of a low degree of accuracy, and to obtain holes for threading, countersinking and reaming. Drilling is used: to obtain irrelevant holes with a low degree of accuracy and significant roughness, for example, for fastening bolts, rivets, studs, etc.; for making holes for tapping, reaming and countersinking.
Drilling can get a hole with an accuracy of 10th, in some cases. 11th grade and surface roughness Rz 320. 80. Drills are of various types and are made of high-speed, alloy and carbon steels, and are also equipped with carbide plates. The drill has two cutting edges. For processing metals of various hardness, use drills with a different angle of inclination of the helical groove.
For drilling steel use drills with an angle of inclination of the groove 18.30 degrees, for drilling light and ductile metals. 40.45 degrees, when processing aluminum, duralumin and electron. 45 degrees. Twist drill shanks can be tapered and cylindrical. Tapered shanks have drills with a diameter of 6.80mm. These shanks are formed by a Morse taper. The drill neck connecting the working part with the shank has a smaller diameter than the diameter of the working part.
The drills are equipped with carbide inserts, with helical, straight and oblique flutes, as well as with holes for supplying coolant, carbide monoliths, combined, centering and tip drills. These drills are made from U10, U12, U10A and U12A tool carbon steels, and more often. made of high-speed steel R6M5.
Sharpening of twist drills. To increase the durability of the cutting tool and get a clean hole surface, coolant is used when drilling metals and alloys. Drillable Recommended coolant fluid. Steel Soap emulsion or a mixture of mineral and fatty oils, Cast iron Soap emulsion or dry processing, Copper Soap emulsion or rapeseed oil, Aluminum Soap emulsion or dry processing, Duralumin Soap emulsion, kerosene with castor or rapeseed oil Silumin Soap emulsion or a mixture of alcohol with scin. ebonite, fiber Dry processing Sharpening is carried out with protective goggles (if there is no transparent screen on the machine).
The sharpening angle has a significant effect on cutting conditions, drill life and therefore productivity. The quality of the sharpening of the drills is checked with special templates with cutouts. Three-notch template allows you to check the cutting edge length, sharpening angle, taper angle, as well as the angle of inclination of the transverse edge.
Features of drilling in difficult-to-machine alloys and plastics
Drilling of heat-resistant steels is carried out with abundant cooling with a 5% emulsion or an aqueous solution of barium chloride with the addition of 1% sodium nitrate.
Drilling in light alloys requires special attention. Drills for machining magnesium alloys have large rake angles; small apex angles (24. 90 degrees); large back angles (15 degrees). For machining aluminum alloys, the drills have large apex angles (65.70 degrees), an angle of inclination of the helical grooves (35.45 degrees), and a clearance angle of 8.10 degrees.
Drilling of plastics can be done with all types of drills, however, their mechanical properties must be taken into account. When drilling some, air is used for cooling, while others are cooled with a 5% solution of emulsol in water. To prevent the exit side from crumbling during drilling, a rigid metal support is placed under it. Drilling in plastics is carried out only with sharpened cutters.
Give a sketch of the part:
What tool was used: twist drills, vernier calipers, locksmith files, metric ruler, hammer, drilling machine, square, radius meter, center punch, chisel, scribe, NS-KS drilling machine.
Safety. When working on a drilling machine, the following safety requirements must be observed: correctly install, securely fix the workpiece on the machine table and do not hold them with your hands during processing; do not leave the key in the drilling machine after changing the cutting tool; start the machine only with firm confidence in the safety of work; do not touch the rotating cutting tool and spindle; do not remove the broken cutting tools from the hole by hand, use special devices for this; use a special wrench or wedge to remove the drill chuck, drill or adapter sleeve from the spindle; not transmit or receive any items through a running machine; do not work on the machine with gloves; do not lean on the machine while it is running.
In the course of this practical work, I learned how to use measuring instruments; learned how to correctly mark out parts; to correctly cut metal; metal cutting; straighten and bend metal; manual filing of metal; drilling, countersinking, reaming; disassembly-assembly of the piston group of the snowmobile “Buran”.
1.Makienko N.I. Locksmith with the basics of materials science 1976,
Pokrovsky B.S., Skakun V.A. Plumbing. 2004y,
3.Kataev A.M. Plumbing. Tutorial,
Gladilin A.V. Industrial training course in engineering technical schools, part 1-2.1987,
Vishnevetsky Yu.T. Car repair mechanic: Device, maintenance and repair of cars. 2006,
6.Brushtein B.Ya., Dementyev V.L. Turning business 1998,
Presentation “Locksmith processing. Metal cutting
This Labor Training Presentation “Locksmith processing. Metal cutting ” allows students to familiarize themselves with the metalworking operation in the simplest form “Cutting metal with a hacksaw” All photos in this presentation. photographs of my students. They really like it.
billets from long products using a hacksaw
This is a locksmith tool. Serves
for cutting zago-
products from varietal
A hacksaw consists of
The hacksaw blade must be secure
fixed in the frame with a tension screw, and the teeth
directed forward from the handle
The forward movement of the hacksaw is working,
since at this time the teeth of the blade cut
metal, but backward movement. single
when working with a hacksaw
Clamp the workpiece securely in a vice
Work with a hacksaw smoothly, without jerking
Cannot cut exactly along the line markings,
because the size of the part will be smaller,
which will lead to an irreparable marriage
When finishing cutting, it is necessary to loosen
press on the hacksaw and hold the cut-off part from below
Do not blow off the shavings and sweep them by hand.
It is necessary to use a broom brush
Test your knowledge
To cut billets from long products, use.
A. hammer and chisel
B. hand saw
B. locksmith file
Test your knowledge
How to install the hacksaw blade correctly?
A. teeth back to the handle
B. teeth forward from the handle
B. teeth up
Test your knowledge
What is the name of this tool?
B. locksmith scissors
B. hand saw
Test your knowledge
What is a hacksaw used for??
A. for cutting billets from long products
B. for filing metal
B. for cutting metal
Test your knowledge
Cutting metal is.
A- dividing the workpiece into parts using a chisel
B. cutting billets from long products at
Turn Rusty Hacksaw Blade into Straight Razor | Wooden DIY. Restoration
using a hacksaw
B. carpentry operation
Test your knowledge
Why you can’t cut exactly along the line markings?
A- the hacksaw blade will break
B. because the part size will be smaller
B. the part will jump out of the vice
Test your knowledge
You need to work with a hacksaw.
A. very, very fast
B. smoothly, without jerking
B. holding a hacksaw with one hand
Test your knowledge
Finishing cutting you need.
A- increase pressure on the hacksaw
B. loosen the pressure on the hacksaw and hold the cut-off part from below
B. take a hacksaw with one hand
Test your knowledge
After cutting, the chips need.
Upgraded Wet Wood Hand Saws
Wet wood hand saw.
The size of the teeth of such a saw. medium or small, shape. triangular. Main distinguishing feature. large semicircular notches every 4.8 teeth.
Saws are used for cutting wet wood. The gaps between the teeth are designed for chips from wet wood, with such a blade, they do not clog the teeth, the speed and accuracy of work increases.
Upgraded saws work along and across the grain with dry and damp wood.
Saw varieties according to the shape and size of the blade
Varieties of hand saws.
Narrow blade saws. Small saws are equipped with a narrow blade. Usage: branches in the garden, small curved workpieces, chipboard, fiberboard, small lumber (slats, bars). Features: it is difficult to make a long cut straight because of the narrow blade; fine teeth make it difficult to cut along grain and damp wood.
Wide blade saws. The most common type of saw, used for cutting different types of wood, along or across the grain. When choosing a blade, first of all, pay attention to the size and shape of the teeth. Usage: small and medium-sized workpieces, along and across the grain, wet and dry wood. Features: the scope of use depends on the size and shape of the teeth, the most convenient saws for self-sharpening.
Butt saw. In such saws, the upper edge of the blade is reinforced (a thicker layer of metal). The rigid blade does not bend during operation. this allows a smooth cut. Usage: shallow, but even cuts in wood of any hardness (grooves, notches). Features: not suitable for sheet material (fiberboard, chipboard), wet wood, sawing along the grain, fine teeth are difficult to sharpen yourself.
Bow saws. In these saws, a narrow blade is attached between the two ends of a steel pipe or wood structure. Usage: a universal saw, they perform most types of work, except for narrow-profile ones, for which they use butt or two-handed saws. Features: the blade changes depending on the work, at first it is difficult to master the cutting technique.
Two-handed saws. They consist of two handles connected by a long and wide blade with large teeth. Used for rough sawing of logs and thick boards or squared beams. The size of the teeth is up to 2 cm, the length of the saw is up to 1.75 cm. Application: initial sawing of large pieces of wood. Features: Only 2 people work, not suitable for small workpieces or sheet material.
Cross-cut hand saws. features of the shape and sharpening of teeth
Tooth shape. equilateral triangle. Tooth size. different. The saw with large teeth is used for softwood cutting and rough cuts. Small toothed saw is used for hardwoods and for finishing cuts.
These saws are designed to work across grain and dry wood. Wet wood clogs up the space between the teeth. productivity and quality of work deteriorates. It is possible to cut along the grain with cross-cut saws, but only small cuts in dry wood and a saw with small teeth.
Cut across the grain of small workpieces with any saw.
Varieties of hand saws for the intended purpose
Garden hacksaw. narrow, often curved cloth, about 30 cm long. The handle is straight or slightly curved. Minimum weight. often sawing branches with an outstretched hand. The sharpening of the teeth is symmetrical so that the cut is made when moving forward and backward. The size of the teeth is small. minimal injury to the tree. The distance between the teeth is increased. wet sawdust clogs less. Using. pruning branches on trees, shrubs.
Hacksaw. this is a hand saw for metal. Canvas. narrow, with fine teeth. During operation, the teeth look from a person, we make the main effort with our hands when moving away from ourselves. Using. cut pipes, corners, rods, cables from metal, plastic. The canvas is tightened with a wing nut. A poorly tensioned blade breaks quickly.
Aerated concrete hacksaw (foam blocks). wide blade 60.80 cm long. Teeth are large, often trapezoidal, with hard alloy surfacing. Using. cutting of aerated concrete building blocks.
Folding hacksaw. these are tourist or garden hacksaws. The canvas is about 30 cm, the handle is slightly longer. Fine, straight teeth, double-sharpened. The blade pivots at the attachment point with a handle. When folded, the teeth are hidden in a groove on the handle. Using. cutting thin branches, boards, slats.
Joiner’s hacksaw. the most common type of hacksaw for wood. Used by joiners, carpenters and ordinary home craftsmen. Using. cut of any construction lumber (timber, board, lath, plywood, fiberboard). The size, shape and sharpening of the teeth vary widely and are selected depending on the work being done.
Hand hacksaw tooth setting
Hand saw tooth setting.
The setting of the saw teeth is necessary so that the blade does not clamp the piece of wood. If you do not do the routing, the cut in thickness will be like a blade, as the cut deepens, the friction force between the tree and the saw increases, the person gets tired faster and the cut is not so accurate.
Hand hacksaw teeth setting. this is the bending of the teeth alternately in different directions from the plane of the blade. As a result of this adjustment, the cut turns out to be slightly thicker than the blade, the friction force is minimal, the person gets tired less, and the work comes out more accurately. Layout is especially important when working with wet wood.
Tools used. Pliers. the least quality wiring. It is difficult to grip the saw tooth all the way from tip to base with pliers. Only the upper part of the teeth is bent. The flexion angle is adjustable “approximately” which also reduces the quality of work. Plates with cuts. captures the tooth along its entire height, bending the teeth completely. But the level of deviation is also adjustable “approximately”.
The most convenient way to set the saw. plate with cuts and a retainer. This tool grabs the teeth along the entire height and sets them apart at a certain angle. Pliers for routing. the wiring angle is adjusted with a screw. The pliers are mounted on the tines and compressed. work done. The fastest and safest way to get the job done.
Sharpening hacksaw teeth
Sharpening a hand saw with a file.
Now a hacksaw is produced with two types of teeth. with heat treatment (hardening) and without. The saw teeth are sharpened only without heat treatment. Saws with hardened teeth are disposable. Hardening increases the hardness of the steel, but makes the teeth brittle and unfit for sharpening. Hardened teeth are darker than the blade. For a saw that can be sharpened by itself, the color of the teeth does not differ from the color of the blade.
Electric machine with special disc. the safest and highest quality option for sharpening teeth. A thin metal disc for an angle grinder is attached to a conventional electric machine, the stop is set at the desired angle and the workplace is ready. Sharpen the edge of the tooth in one pass so that the machine does not grind a lot of metal.
File. a medium-sized triangular file with a fine cut is suitable. A file will not work. small working plane and saw tooth will sharpen unevenly. A large file will not work. it processes only the edge of the tooth, the size does not allow sharpening the entire edge. A file with a large cut will not work. tears metal, instead of a flat edge on the teeth, jaggedness is obtained.
Two options for fixing the saw: deep vise (saw vertically, teeth up the entire length above the vise jaws) or horizontally on the table (teeth hanging from the table). It is more convenient and safer in a vice. While fixing horizontally on the table, press one side with a heavy object, and hold the other with your hand.
File movements over the entire surface of the tooth. The angle of sharpening should be repeated with the manufacturer Effort the file in the direction, as if removing chips from a file. In most cases, 3-4 file movements are enough to sharpen one side of the tooth.
Angle Grinder. At first glance, a quick and convenient way to sharpen a hand saw, but it is not. The disc of an angle grinder removes a lot of metal and after even a slight incorrect hand movement, irregularities remain on the saw teeth or the point is heavily grinded. The saw is fixed in a vise, the movement of the disc from the point to the base of the tooth. Use a thin metal disc and a small angle grinder. it is easier to operate, less hand fatigue and therefore fewer defects in work.
Universal hand saws
Universal hand saw for wood.
Universal hand saws for woodworking come in a variety of tooth shapes and sizes. There are many combinations. Most often, on one blade, teeth of a triangular and trapezoidal shape.
Triangular-shaped teeth make the cut, and trapezoid-shaped teeth widen the kerf and sweep away the chips when the saw moves backwards.
There are saws with standard triangular teeth, but of different sizes. The principle of operation of such a canvas is similar. small teeth act on the tree when moving forward, and large ones during reverse.
Universal saws cut along and across the fibers. Wet wood is also subject to them, but only with short cuts.
A feature in the maintenance of such saws. It is difficult to sharpen the canvas yourself, and in most cases it is impossible. When buying a saw, keep in mind that it is disposable and will become unusable after the first “caught” nail.
We understand the varieties of hand saws for wood
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A DIYer can have one universal saw or 2.3 specialized / In a carpentry or furniture workshop without 5.7 varieties of saws, it is hard and unproductive to work. The saw is selected according to the nature of the cut (along or across the fibers), the density of the material (hard, soft wood or chipboard, plywood), the thickness of the workpiece.