To control the manufacture of parts, assembly and repair of mechanisms and machines, various measuring instruments are used - tools and devices. Measuring tools include vernier tools, micrometers, calibers, rulers, surface plates, etc.
The main characteristics of the measuring instruments are: division and division of the scale, the initial and final values of the scale, the range of the scale readings, and the limits of measurement.
Scale division is the distance between two adjacent strokes.
The scale division is the value of the measured value corresponding to two adjacent scale marks.
The initial and final value of the scale is the smallest and largest value of the measured values indicated on the scale of the instrument or tool.
The range of the scale readings is the range of the scale values, limited by its initial and final values.
Measurement limits are the largest and smallest quantities that can be measured by a given instrument or device.
Linear dimensions in mechanical engineering are usually indicated in millimeters without recording the name. If the size is indicated in other derived units, then it is recorded with the name, for example: 1 cm, 1 m, etc.
The most common instruments for measuring linear quantities in mechanical engineering are metal rulers, vernier tools, micrometric instruments, etc.
Measuring metal rulers used for irresponsible measurements with low accuracy. They are manufactured with upper measurement limits up to 150; 300; 500; 1000 mm. The graduation is usually 1 mm. Measurement error 0.5 mm.
Vernier tools used for more accurate measurements. These include calipers used to measure the outer and inner diameters, lengths, thicknesses of parts, etc. (Figure 1); depth gauges intended for measuring the depths of blind holes, measuring grooves, grooves, protrusions (Figure 2); height gauges, which are used to accurately mark and measure heights from flat surfaces (Figure 3).
In all the indicated caliper instruments, verniers are used, according to which fractional fractions of divisions of the main scales are counted.
Figure 1 Vernier caliper ШЦ-I 1 - barbell; 2 – sponges for measuring internal dimensions; 3 - movable frame; 4 - clamp; 5 - vernier scale; 6 - depth gauge ruler, 7 - sponges for measuring external dimensions
Among caliper tools, the most widely used are calipers ... They are of three types:
ШЦ-I (measurement range 0-125 mm and measurement accuracy 0.1 mm);
ШЦ-II (measurement limits 0-200 and 0-320 mm, measurement accuracy 0.05-0.1 mm);
ШЦ-III (measurement range 0-500; 250-710; 320-1000; 500-1400; 800-2000 mm, measurement accuracy 0.1 mm).
With closed jaws, the zero stroke of the vernier coincides with the zero stroke of the main scale. If you move the jaws of the caliper apart by 0.1 mm, then the first stroke of the vernier coincides with the second stroke of the bar. If you move the jaws apart by 0.2 mm, then the second and fourth strokes will coincide, by 0.3 mm - the third and sixth, etc.
Thus, when measuring with a vernier caliper, whole millimeters are counted directly on the barbell scale to the zero line of the vernier, and fractional (in this case, tenths) of a millimeter - on the vernier scale. In this case, the fractional value (number of tenths of a millimeter) is determined by multiplying the measurement accuracy (0.1 mm) by the ordinal number of the vernier stroke (not counting zero), which coincides with the stroke of the barbell. When reading the readings, the caliper is held directly in front of the eyes (Figure 4).
In any production that involves the manufacture of something, it is impossible to do without measurements. Regardless of whether GOST requires it or you are creating a new product, you still have to measure it. We will now talk about how and what to measure correctly. Discarding specialized geodetic instruments, without returning to antiquity to a string with knots and a stick with notches, and also without looking into the future with laser rangefinders, we will discuss simple, convenient, most commonly used measuring instruments.
Purpose and types
Speaking about their purpose, measuring instruments are classified according to their field of application into:
- construction;
- carpentry;
- locksmiths.
A separate group is a universal measuring tool that can be used in all or several industries.
By types, tools are divided as follows:
Such a division into classes and types of measuring instruments is necessary for their professional use in work, compliance with the rules of storage and operation, purchase in stores and delivery from a warehouse in factories.
Construction Measuring Tools
- Roulette... Used to measure linear dimensions of length, width, height. It is a body made of a solid material (plastic, metal), inside which there is a metal or polymer tape. They are produced in different widths and lengths, but with the same scale, the graduations of which are 1 mm. Roulettes are available with a manual or mechanical (spring) winding principle.
- Water level. It is used for horizontal marking in height. Consists of a flexible polymer tube (length from 5 to 30 m) and two volumetric flasks at the ends. Works on the principle of communicating vessels.
- Level (spirit level). It is necessary to determine both horizontal and vertical indicators of structures. Made from various materials (wood, plastic, aluminum). The length is from 30 cm to 2.5 m. It mainly has three windows with glass tubes. The tubes are not completely filled with antifreeze liquid. The principle of operation is vertical air lift.
- Plumb line... Used to set vertical values during installation and construction. It has a simple construction of a cord on which a cone weight is suspended. Sometimes in strong winds, to compensate for lateral vibrations, the load is placed in a container with water.
- Gon... Made of wood or metal. Has a length of each side up to 1 m. It is irreplaceable in the work on the construction of buildings for checking right angles.
- Malka... Like a square, it can be metal or wood. The difference is that the two wings (clip and ruler) are hinged. It is mainly used in the construction of roofs for the installation of rafter pairs. Having set the desired angle, we fix it with a wing nut and check the structure.
Carpentry measuring tools
Considering the contiguity of some professions and the versatility of the measuring tool, we will single out only the meter and the triangle separately. Roulette is generally a universal tool, and we have already talked about the square and the bevel. They with a shorter side length (up to 50 cm) are widely used by carpenters. A vernier caliper is also used, for example, to select drills or check the diameter of holes, but we will talk about it later.
- Meter... The main material is wood and stainless steel. A plastic version was also produced, but due to its fragility it did not find wide application. The name speaks for itself - meter, graduation 1 mm. Its main difference from the meter ruler is that it consists of separate sections that fold and unfold if necessary.
- Triangle... Everyone from school remembers this instrument and the magnitude of its angles - 90, 60, 45 degrees. That is why it is widely used by all carpenters. Usually, the square has a bevel at 45 degrees, but, firstly, not everyone, and secondly, the dimensions do not always allow them to be used. This is where the triangle comes in handy. The main material is plastic, as well as wood or metal.
Locksmith measuring tools
Taking into account the specifics, the scope of application, as well as the conditions when the dimensions range from 0.1 mm to 0.005 mm, we can say that the locksmith is the most accurate measuring tool. And it's not just about accuracy. The work itself requires care, and the measuring tool requires knowledge and experience. Often, the same device is used to measure different parameters.
Let's look at the irreplaceable assistant - calipers... Its upper lips are used to measure the internal dimensions of parts, and the lower ones are used to measure external parameters. In addition, the caliper has a depth gauge on a movable frame. But that's not all. On the main shaft there is a scale for counting whole millimeters (graduation - 0.5 mm), and in the frame cutout there is a Vernier scale for counting fractions of millimeters (graduation 0.02 mm). There is also a locking screw that secures the frame to the shaft.
Yardstick is a polished steel strip 20-30 cm long with 1 mm graduations. It is used for linear measurements that do not require high accuracy.
For a more accurate measurement, as well as measurement of angles, measuring instruments such as micrometer and goniometer. They also have two scales - basic and vernier. Often used calipers and bore gauge for measuring the outer and inner dimensions of parts, respectively.
In the arsenal of a specialist there is also a variety of control and measuring tools:
- calibration rulers of various configurations (double-sided, three-sided and tetrahedral);
- corner and reference tiles;
- measuring indicator;
- various probes.
Storage conditions
Taking into account the materials from which the measuring instruments are made, it becomes clear that they cannot be stored under the same conditions. If plastic and plastic tools are less susceptible to moisture, then wooden and especially metal ones are afraid of water ingress. In this regard, they must be stored in a dry ventilated area. In addition, the wooden tool must be protected from direct sunlight to prevent it from drying out. Precision instruments are best stored in protective leather cases and some instruments in solid wood or plastic boxes.
Measuring Tool Operation
First of all, the measuring tool you are working with must be in good working order, clean, and free from traces of rust or oxidation. No mechanical impact (shock, pressure, bending) is allowed. Try to avoid dropping the tool, getting water on it. Read the instructions, if any, before work. Skillful correct handling of the measuring tool is the key to quality work.
All cars, machine tools, devices and tools are made up of many parts. Each of them has a specific shape and size. The calculation of the parameters of parts requires high accuracy, which can only be observed when using measuring tools or measuring machines.
Classification of measuring instruments
There are several types of measuring instruments, distinguished by certain parameters.
By type of work.
There are the following types of tools:
- building;
- locksmith;
- carpentry.
Most of the tools used in measuring operations are universal. Therefore, this classification is very arbitrary.
By material of manufacture... Measuring devices can be made from the following materials:
- metal;
- wood;
- plastic.
Any tool can be combined, that is, made of several materials, for example, metal and wood.
By way of use... According to this parameter, manual tools are distinguished, mechanical and automatic.
By design features... The design of the instrument used for measuring work can be simple or complex.
This classification helps ensure the correct use and storage of the tool.
Application of measuring machines
To make accurate measurements, not only hand-held measuring instruments can be used, but also special machines called coordinate measuring equipment. The peculiarity of this equipment lies in the possibility of making measurements in three coordinates, which ensures the maximum accuracy of calculations.
The design of the machines resembles a table with working heads equipped with sensors. To make a control measurement, the workpiece is placed on the table, and the sensors read the parameters of the part.
Machines can take data in two ways:
- contact, providing for the use of a probe;
- contactless, in which reading occurs by directing a light signal to the surface of the part.
Hand construction tool
Roulette... The main tool that no builder can do without is a tape measure. Roulette is a kind of ruler made in the form of a metal tape with divisions equal to 1 mm. The tape is wound into a housing, which can be made of either plastic or metal. The tape can be of various widths and lengths.
Of course, a tape measure is universal, required for measuring work in any field of activity.
Spirit level (level)... With the help of this device, the flatness of the horizontal and vertical surfaces is determined. The length of the level can vary from 0.3 m to 2.5 m. The body of the level is made of any light material, for example, plastic, and is equipped with several windows.
A glass tube, partially filled with a special liquid, is visible through the windows. It is this liquid that allows you to determine the evenness and level of the slope of the surface.
It is the simplest but indispensable measuring tool that every builder uses. The plumb bob represents a rope (twine), at the end of which a metal cone-shaped weight is tied. It is used in cases where it is necessary to control the verticality of the work, for example, when masonry.
Square and malka... The square is made of wood or metal and is used to derive right angles. Malka is made from the same materials. Its design consists of a clip and a ruler, fastened together by a hinge. If the square can be used in any area of construction, malku is most often used when installing rafters.
Hand locksmith tool
Locksmith tools are most often used in the field of metalworking and mechanical engineering and are considered the most accurate. With its help, it is possible to calculate the maximum and minimum dimensions with an accuracy of 0.1 mm to 0.005 mm.
In addition to the universal ruler and tape measure, the locksmith has to use the following devices:
- calipers;
- height gauge mass;
- micrometer.
Calipers... This hand tool consists of a graduated bar and a moving frame. The caliper is also equipped with upper and lower jaws. The upper jaws allow you to measure the inner parts of the workpieces, and the lower ones - the outer ones.
This device differs from a caliper in the presence of a support. The height gauge allows you to mark the details of the height and depth of the holes, as well as the location of other elements.
Micrometer... The design of this device consists of a tube with a scale, a sleeve and a tip. Use a micrometer if you want to calculate the value to the nearest 0.01 mm. The depth of holes in parts is measured with a micrometer depth gauge - a kind of micrometer.
Hand carpentry tools
In addition to universal devices, specialized carpentry measuring tools are used in carpentry workshops. Every joiner uses the following:
- folding rule;
- triangle with angles 90, 60, 30 ° or 2 x 45 °;
- calipers, allowing for marking on wooden structural elements;
- internal gauge - a device for marking and measuring the parameters of grooves and holes;
- goniometer - a device consisting of a scale and an arc mounted on a plate;
- a thickness gauge with or without a vernier helps to draw parallel lines to surfaces.
Equipment operating conditions
Preserving the functionality of the devices allows periodic maintenance and checks of their condition. Measuring instruments with complex design features are most susceptible to breakdowns.
Each device comes with an instruction manual, which must be read before use. The instructions set out all the rules of work that are relevant specifically for this model.
Automatic and electronic models of measuring machines are sensitive to temperature and humidity indicators. Equipment that uses a non-contact measurement method reacts especially sharply to them.
It is equally important to provide the tool with decent storage conditions. Tools made of wood and metal are sensitive to moisture. And plastic is able to deform in direct sunlight and when exposed to high temperatures. Therefore, all instruments should be stored in cases or boxes in a dry place.
Compliance with these guidelines will ensure the quality and accuracy of measurements and will also help extend the life of your instruments.
To determine the actual dimensions of parts, various measuring instruments are used, which are divided into universal, or scale, gauges, or scaleless, and accurate.
Universal measuring instruments include: ruler, meter, vernier caliper, depth gauge, micrometer, shtikhmas, goniometer, etc.
To measure individual elements of parts that cannot be directly measured with conventional instruments, auxiliary tools are used: calipers, internal gauge, reysmass, etc.
Measuring tools are also divided into working and control. The working tool is intended for use in workshops, the control tool is for checking the working tool.
In addition, limit measuring instruments are used in serial production.
No matter how carefully the dimensions of the part are measured, the measurement results are not accurate enough, on the one hand, due to the imperfection of the measuring instruments, on the other, depending on the measurement method. The deviation of the size obtained by measurement from the actual one is called the measurement accuracy, and the magnitude of this deviation is the degree of measurement accuracy. It is clear that the more accurately you need to measure the part, the better the measuring tool and measurement methods should be. Therefore, depending on the accuracy of measurements, measuring instruments are also used, the most common of which are as follows:
Steel ruler. Manufactured in lengths from 150 to 500 mm (Fig. 207) and is used to measure small lengths. The accuracy of measuring with a steel ruler reaches 0.25 -0.5 mm, depending on the skill of the measurer.
Meter... To measure large lengths, meters are used (Fig. 208), which are made of wood and steel. Wooden meters are only folding and are usually used for rough measurements. Steel meters are made folding and in the form of a tape measure. Folding steel meters, like wooden ones, are used for rough measurements. The disadvantage of folding wooden and steel meters is that they loosen the hinges of the joints, as a result of which they give large errors. Therefore, when measuring, it is better to use a tape measure. One- and two-meter tape meters are manufactured. The measurement accuracy with such meters is 0.25-0.5 mm, that is, the same as when measuring with a steel ruler.
Calipers... A caliper serves for more accurate measurements of lengths and diameters (Fig. 209). It consists of a bar 1 with graduations in millimeters marked on it. At its left end there is a fixed jaw 2. Movable jaw 3 with frame 4, vernier and a fixing screw are connected to the slider 6 by means of a micrometric screw 5. A knurled nut 7 is screwed onto the micrometric screw 5. The slider 6 is fixed to the rod with a screw 3.
In addition to what has been described, there are also calipers with a depth gauge (Fig. 212).
With a vernier caliper, you can measure with an accuracy of 0.1 - 0.025 mm.
The vernier caliper is usually divided into 10 equal parts, and each division is 0.9 mm, therefore, 10 vernier divisions are equal to 9 bar divisions, i.e. 9 mm.
If the jaws of the caliper are moved close, then the first stroke of the vernier, indicated by zero, coincides with the zero division of the bar, and the tenth division of the vernier, with its ninth division (Fig. 210). The difference between the first division of the rod and the first division of the vernier is 0.1 mm, for the second division - 0.2 mm, the third - 0.3 mm and the ninth - 0.9 mm. Therefore, if the movable jaw is moved to the right so that the first division of the vernier coincides with the first division of the bar, then 0.1 mm must be added to the whole number of millimeters to the left of the zero division of the vernier; when the second division coincides - 0.2 mm, the third - 0.3 mm, etc.
The accuracy of measurement with a caliper is equal to the ratio of one division of the rod to the number of divisions of the vernier. If the vernier is divided into 10 equal parts, then the measurement accuracy will be 0.1 mm. To set the vernier caliper to a given size, move the movable jaw to the right until the zero division of the vernier coincides with the desired integer number of millimeters on the rod, and continue to move the jaw in the same direction until the required division on the vernier coincides with the nearest to it by dividing on the bar. The division of the vernier, which coincides with any division of the rod, will indicate the number of tenths of a millimeter. If, for example, it is required to install a vernier caliper to 38.4 mm, then to do this, release the screw fixing the frame and move it so that the zero division of the vernier coincides with the 38th division of the rod. If the vernier caliper is equipped with a slider, then the setting of the vernier to a size of 0.4 mm is carried out by rotating the nut 7 until the fourth division of the vernier coincides with the nearest division of the rod (Fig. 211, a).
To read the size of the part measured with a caliper, it is necessary to note with which division of the rod the zero division of the vernier coincides. The coincident division will show the size of the measured element of the part. If the zero division of the vernier does not coincide with an integer number of divisions on the rod, then we notice on the rod the nearest number to the left of the zero of the vernier and add to it the number of fractions of a millimeter on the vernier, which coincides with the closest division of the rod.
FIG. 211, b shows the size of 45.3 mm, respectively, the measured size of the part with a caliper.
FIG. 210 shows a hole measurement with a lower pair of jaws. In this case, the thickness of the ends of the jaws, which is usually 8 or 10 mm, must be added to the size indicated with a caliper.
As already mentioned, some calipers have a device for measuring depth, the so-called depth gauge (Fig. 212).
The depth gauge is attached to the frame of the movable jaw. The measured depth is calculated in the same way as when measuring the thickness or diameter of the part.
Micrometer... A micrometer (Fig. 213) is a more accurate measuring instrument than a vernier caliper. With a micrometer, measurements can be made with an accuracy of 0.01 mm.
The micrometer consists of a flat bracket 7, a heel 2, a spindle 3, a clamping ring 4, a tube with graduations 5, a sleeve 6 and a ratchet 7. A movable spindle 3 with a thread having a pitch of 0.5 mm is connected to the tube 5.
By rotating the sleeve, you can set the spindle to the desired value. In the case when the spindle rests against the heel, i.e. when the distance between the heel and the end of the spindle is zero, the zero division of the vernier should be at the zero division of the tube. The ratchet head is connected to the ratchet inside the micrometer. The ratchet allows you to maintain a certain constant pressure of the spindle on the measured object. If this pressure is exceeded, the head begins to overshoot, producing a crackling sound.
There are divisions on the tube and the beveled edge of the sleeve, the number of which on the sleeve is 50, and on the tube, corresponding to the nominal size of the micrometer. The distance between the marks on the tube is 0.5 mm. With one complete revolution of the sleeve, the spindle moves 0.5 mm. Thus, when the sleeve is rotated one notch, the spindle will move 0.01 mm.
By divisions on the tube, an integer and half millimeters are counted, and by divisions into a sleeve, hundredths of a millimeter.
The sum of the readings on the tube and sleeve shows the distance between the heel and the end of the micrometer spindle.
FIG. 214, a shows the divisions of a micrometer set to a value equal to 14.31 mm, and in FIG. 214, b - by 12.38 mm.
When measuring with a micrometer, in order to avoid errors, it is necessary to rotate not the sleeve, but the ratchet head from the moment the spindle approaches the workpiece at a distance of about 1-2 mm.
Micrometric shtikhmas... Shtikhmas (Fig. 215) is used to measure the diameters of the holes and is similar in structure to the measuring device of a micrometer. Shgikhmas consists of a sleeve equipped with a tip with a spherical surface 2. The sleeve 7 includes a micrometric screw with a spherical end 
surface 5. The measurement results are counted by divisions on the tube 3 (whole numbers and half millimeters) and by divisions of the sleeve 4 (hundredths of a millimeter). Thus, the measurement result is the sum of two readings.
As with a micrometer, there are 50 divisions on the beveled edge of the sleeve, and millimeter divisions are applied to the 3 gauge tube.
If the sleeve 4 makes one full turn, then the screw with the tip 5 will move by 0.5 mm, therefore, when the sleeve is turned by one division of its scale, i.e. by 1/50 of a turn, the screw will move by 0.01 mm.
FIG. 215 shows that the distance between the ends of the tips 2 and 5 is 82 mm. This value was obtained from the addition of two sizes: the nominal size of the gauge equal to 63 mm (the distance between the measuring ends 2 and 5 is taken as the nominal size of the gauge when the zero of the vernier coincides with the zero division of the tube) and counting along the divisions of the tube and the vernier. In this case, this value is 19 mm. Thus, 63 + 19 = 82 mm.
Micrometric depth gauge(Fig. 216) has the same device as the micrometer. The depth gauge consists of a crosspiece 1, which has a measuring plane rigidly attached to the stem 2. Inside the stem, there is a screw with a measuring rod 3 and a retaining ring 4, sleeve 5 and a ratchet 6. When measuring, the crossbar is pressed against the workpiece with the measuring plane and the measurement is performed as in measurements with a micrometer.
Protractor... A protractor is a device used to construct and measure the angles of parts. Protractors are made with and without vernier. The most widespread in the USSR are goniometers with a vernier, from the factories "Red Instrument Maker" "" and "Caliber".
The protractor of the "Red Instrument Maker" plant (Fig. 217) consists of a half-disk 1 with a ruler attached to it 2. A movable ruler 3, rigidly fastened to a vernier 4, rotates around the O axis. 0 to 90 °, a square 6 is put on the ruler 3. The measurement accuracy for this goniometer is within 2 ". A more perfect goniometer is the goniometer of the "Caliber" plant, designed by DS Semyonov (Fig. 218, a). This goniometer consists of an arc 1 with a graduated scale applied on it, along which plate 2 and a vernier 3 rigidly attached to it move. plate 2 has a holder 4, with which the square 5 with the ruler 6 is fixed.
The plate 7 is rigidly connected to the arc 1. The main degree scale is divided into 130 °, however, by installing the measuring parts of the protractor in different positions, angles from 0 to 320 ° can be measured (Fig. 218, b). The measurement accuracy for goniometers of this design is 2 ".
To do, for example, an angle reading? according to such a goniometer, when the square takes the position marked with the letter A (Fig. 218, a), it is necessary first of all to see between which divisions the zero division of the vernier is located. FIG. 218, and this division is located between the numbers 33 and 34 of the main degree scale. After that, find on the right that division of the vernier, which coincides with one of the nearest divisions of the main scale. In this case, the division corresponding to 10 "coincides. Therefore, the sought angle a is 33 ° 10". It is easy to understand where the 10 "was obtained. The division corresponding to ten minutes is the fifth to the right of the zero division of the vernier. Since the price of each division of the vernier is 2", then for five divisions this will be 2 "X5 = 10".
Suppose, for example, it is required to measure the angle p corresponding to the position of the square marked with the letter B. It is easy to see that the angle? is an obtuse angle consisting of the sum of the angles: a and the right angle.
The value of the angle a was determined earlier and is equal to 33 ° 10 ". Thus, the angle? = A + 90 ° = 33 ° 10" + 90 ° = 123 ° 10 ".
Caliper and bore gauge(Fig. 219, a and b) are auxiliary tools and are used to measure quantities by transferring the size from the product to the measuring tool or vice versa.
A caliper measures the outer dimensions of the parts, an inner gauge - the inner ones.
Caliper and bore gauge consist of two steel legs connected by a hinge.
The measurement accuracy with these instruments is low.
Reismas... Reismasom (Fig. 220) is used when drawing parallel lines on parts, when marking work and measuring inaccessible parts of parts that cannot be measured with commonly used tools. The simplest planer (Fig. 220, a) consists of a steel rod moving along the groove of the rack and then fastened to the rack with a lamb. The rack of the reysmass is fixed on the stand. The work of the reeler is carried out on a marking plate.
Shtangenreismas(Fig. 220, b). For accurate measurements and marking work, a height gauge with a vernier is used. A movable device with a scribe and a vernier moves along a ruler and is fixed in the desired position with screws. The exact setting on the vernier is done in the same way as for a vernier caliper.
Thread gauges... To determine the thread pitch or the number of threads per 1 "thread gauges are used on threaded products (Fig. 221). Thread gauges are made for different thread systems and are a set of steel combs enclosed in a block.
The determination of the thread pitch or the number of threads per 1 "is made by selecting the profile of the comb corresponding to the angle of the thread profile. The comb will accurately indicate the thread pitch or the number of threads per 1" (Fig. 221, b).
To ensure the correctness of the found thread pitch or the number of threads per 1 ", it is necessary to additionally measure the outer diameter of the thread using a vernier caliper and check the data obtained with the data of the corresponding thread standard. Otherwise, the measurement must be repeated.When determining these values, it is necessary to carefully look whether the thread gauge is correctly selected, that is, whether the angle of the thread gauge profile corresponds to the profile of the threaded product.For more accurate measurements of threads, special thread micrometers, thread gauges, universal and instrumental microscopes are used.
In the manufacturing process
Measuring tool - a tool designed to measure linear objects.
Simple measuring tools
Yardstick
Measuring Ruler - the simplest measuring geometric tool, the ruler has marked divisions, multiples of the unit of length (centimeter, inch), which are used to measure distances.
Yardstick
Vernier tool
Vernier tool - a tool for measuring and marking linear dimensions:
a) holes and shafts (vernier caliper);
b) depth and length (height gauge, height gauge);
c) gear teeth (caliper).
The accuracy of its measurement is tenths of a millimeter.
Calipers
Vernier caliper is a versatile tool designed for high-precision measurements of external and internal dimensions, as well as hole depths.
2) movable frame
3) bar scale
4) sponges for internal measurements
5) sponges for external measurements
6) depth gauge ruler
8) screw for clamping the frame
Gauge depth gauge
A caliper is used to measure the depths of grooves, grooves, ledges, etc. It differs from a caliper in that it does not have movable jaws on the rod.
Height gauge
Measuring device. Designed to measure the depth of grooves and depressions.
Protractor
Protractor is a goniometer designed to measure geometric angles in various structures (outer and inner corners of products.), In parts and between surfaces (mainly by the contact method) and between distant objects (optical method). The measurement is carried out in degrees, based on a ruler scale, a ruled-circular scale (with a mechanical pointer or arrow), vernier or in electronic form, depending on the type of device.
The design of the goniometers allows for marking work on a plane.
Micrometric instrument
Micrometer smooth
Smooth micrometer - a tool for measuring external linear dimensions.
Readings on the scales of a smooth micrometer are counted in the following order:
· On the scale of the stem read the mark near the line closest to the end of the bevel of the drum;
· On the scale of the drum read the mark near the stroke closest to the longitudinal stroke of the stem;
· Add both values and obtain the micrometer reading.
For convenience and acceleration of reading readings, there is a smooth micrometer with digital display.
Threaded micrometer
A threaded micrometer is used to measure the average diameter of metric and inch threads and has the same device as a conventional micrometer, but differs from the latter only in the presence of a hole in the heel and spindle, where special replaceable inserts of various shapes are inserted: prismatic, conical, flat, ball.
a - general view,
b - inserts,
c - measurement techniques;
1 - heel
2 - spindle,
3 and 5 - threaded inserts,
4 - part to be measured
For each micrometer, sets of such inserts are given, which fit into the case in pairs and are intended for measuring the thread with a pitch of 1 -1.75; 1.75-2.5, etc. The profile angle of the inserts must match the profile angle of the tested thread.
The average thread diameter of part 4 is checked with a prismatic insert 5 inserted into one of the threads; on the other hand, tapered insert 3 is inserted into the thread root perpendicular to the thread axis.
micrometer scales.
Micrometric depth gauge
Designed to measure the depth of grooves, holes and heights of ledges.
Micrometric depth gauges have the same device as micrometers, only instead of a bracket there is a base (90x12 mm) 1 with a measuring rod 2. The base and measuring rod are hardened. Each micrometer depth gauge is equipped with three interchangeable rods with a measurement range of 0-25 mm; 25-50 mm; 50-75 mm; 75-100 mm.
1 - base, 2 - rod
Internal micrometer
An internal micrometer is a device with which a more accurate measurement of holes is made using the absolute method; it also has replaceable extension cords.
4) Tool with a dial gauge:
Wall gauge (thickness gauge)
Wall gauge is an industrial device designed to control and measure external and internal dimensions, wall thickness of workpieces, grooves. Stenometer is convenient for measuring pipe wall thickness. Wall meter measuring range from 25 to 50mm. Graduation 0.1mm to 1mm, measurement depth 160mm, smallest hole diameter 20mm. The margin of error is ± 0.10. Indicator wall gauge is made of carbon or stainless steel. Indicator wall gauge - a measuring device used to measure linear dimensions by the contact method. Measurement type - absolute.
The indicator wall gauge consists of a fixed upper frame (body) with a handle, a movable lower frame, which is pressed against the fixed frame by means of a return spring. A dial indicator is attached to the upper frame, the measuring rod of which rests against the horizontal protrusion of the lower frame. When releasing the lower frame, the protrusion of the lower frame moves the indicator rod. The movement of the measuring rod is converted by the dial mechanism to the movement of the arrow of the measuring head. The count is taken from the head scales: main and auxiliary.
Indicator bore gauge
Indicator bore gauge - a device for internal measurements. Indicators are intended for relative or comparative measurement and verification of deviations from the shape, dimensions, as well as the relative position of the surfaces of the part. These tools check the horizontal and vertical position of the planes of individual parts (tables, machine tools, etc.), as well as the ovality, taper of shafts, cylinders, etc.
1-dial indicator
6-tee inside gauge head
8- measuring rod
9- lever
10-bar
11- coil spring
In addition, indicators are used to check the runout of gears, pulleys, spindles and other rotating parts. They are also of the watch and lever type.
The most widespread are dial indicators, which in combination with other instruments (internal gauges, depth gauges, etc.) are used to measure internal and external dimensions, parallelism, flatness, etc.
Hour indicator
It consists of a body 4, in which a measuring rod 7 (spindle) with a toothed rack cut on its surface passes through the entire long sleeve 6. 
5) Limit calibers
Measuring plugs
For checking hole diameters. The non-passage side differs from the bore side in the shorter length of the measuring part or the presence of a groove in the handle or insert 
Measuring clips
For checking shaft diameters and lengths.
6) Templates
Template - a plate (pattern, stencil) with cutouts, along the contour of which drawings or products are made, or a tool for measuring dimensions.
For measuring outside and inside angles. Checking the deviation from the angle is carried out by observation "in the light".
Curve rulers
The ruler is designed to check the straightness by the light slit method "in the light" and is used for curving, locksmith and control operations.
Straight rulers are made of tool carbon or alloy steel with high precision and have thin working edges, called ribs or blades, with a radius of curvature of 0.1-0.2 mm, so that deviations from straightness can be very accurately determined.
Checking plate
Checking plate - a metal plate with normalized flatness and surface cleanliness: designed to control the flatness of parts and marking work; used as a mounting surface for assembly, measurement and verification.
Squares
Square test squares are designed to check right angles (90 °) and are used in fitter-assembly and curvature work to control the mutual perpendicularity of parts.
Radius templates
Radius templates are designed to evaluate the radii of convex and concave surfaces. Three sets of radius templates are made. Each set contains plates for control of both outer and inner radii. The design of the set holder provides the possibility of free replacement of the template, as well as regulation of the smoothness of their rotation on the axis.
Threaded templates
Thread templates are used to define the pitch and angle of the thread. Threaded templates are steel plates with teeth located along the axial thread profile. Thread templates are available for measuring inch or metric threads.
To determine the pitch and angle of the thread profile, the thread template is aligned with the thread of the part to be checked so that the teeth of the template fit into the thread hollows. Further, according to the tightness of the edges of the threaded template to the thread, the correspondence of the pitch and angle of the thread profile to the pitch and angle of the profile of the threaded template is determined.
