What are calibers made of? Measuring control by calibers
Calibers - measuring control tools designed to verify compliance of the actual dimensions, shape and location of the surfaces of parts with the specified requirements.
Gauges are used to control parts in mass and serial production. Calibers are normal and extreme.
Normal caliber- an unambiguous measure that reproduces the average value (the value of the middle of the tolerance field) of the controlled size. When using a normal gauge, the suitability of the part is judged, for example, by the gaps between the surfaces of the part and the gauge, or by the “tightness” of the resulting interface between the controlled part and the normal gauge. Gap assessment, therefore, control results largely depend on the qualifications of the inspector and are subjective.
Limit calibers- a measure or set of measures that ensures control of the geometric parameters of parts according to the highest and lowest limit values. Limit gauges are made to check the dimensions of smooth cylindrical and conical surfaces, the depth and height of ledges, and the parameters of threaded and splined surfaces of parts. Gauges are also made to control the location of surfaces of parts, standardized by positional tolerances, alignment tolerances, etc.
When testing by limit gauges, a part is considered suitable if the pass gauge passes under the influence of gravity, and the non-go gauge does not pass through the controlled element of the part. The control results are practically independent of the operator’s qualifications.
By design, calibers are divided into plugs and staples. To control holes, plug gauges are used, and to control shafts, clamp gauges are used.
By purpose, calibers are divided into workers and control .
Workers calibers are designed to control parts during their manufacturing and acceptance. Such calibers are used at enterprises by workers and inspectors of technical control departments (QCD). Tests gauges are used to control rigid working limit gauges or to adjust adjustable working gauges.
A set of working limit gauges for testing smooth cylindrical surfaces of parts includes:
Go-through gauge (PG), the nominal size of which is equal to the largest maximum shaft size or the smallest maximum hole size;
No-go gauge (NOT), the nominal size of which is equal to the smallest limit shaft size or the largest limit hole size.
The basis for the design of smooth gauges laid Taylor's principle or the principle of similarity, according to which pass-through gauges should be a prototype of the mating part and control in a complex all types of errors of a given surface (checking the diameter and shape errors, including deviations from the straightness of the hole axis). This ensures the assembly of the compound. Non-go gauges must provide element-by-element control (control of the actual dimensions), therefore, the contact between the working surfaces of the gauges and the controlled surface must be point-like.
Fully compliant with Taylor's principle the working gauge for checking the hole must have a pass side in the form of a cylinder with a length equal to the length of the mating or controlled surface (full plug), and a non-pass side in the form of an incomplete plug in the form of a rod with spherical tips. The working gauge for shaft control must have a pass side in the form of a ring with a length equal to the length of the mating or controlled surface, and a non-pass side in the form of a bracket with knife surfaces. In practice, due to the peculiarities of manufacturing and control technology, a violation of the Taylor principle is often observed, for example, gauges for testing small diameter holes are made in the form of full plugs, and for testing shafts - in the form of brackets.
Control of hole sizes is usually carried out with go-through and no-go plug gauges inserted into a common handle (Fig. 3.77 A).
Shaft gauges are usually bark in the form of brackets with plane-parallel working surfaces (Fig. 3.77 b).
b | V |
Rice. 3.77. Sketches of calibers
If the go and no-go gauges for checking holes are made in the form of full plugs, then the no-go plug has a shorter length than the go-through one. For holes of large diameters, gauges with working surfaces in the form of an incomplete plug are more often used, for example, a sheet plug with cylindrical working surfaces, and the length of the working surfaces of a non-go-through plug is significantly less than that of a go-through plug. Each plug controls several cross sections of the hole (at least two mutually perpendicular sections are controlled).
When checking shafts clamp gauge and the surface is checked in several sections along its length and in at least two mutually perpendicular directions of each section.
If the parts are suitable, then, in accordance with the name, go-through gauges (PG) should pass through the controlled surfaces under the influence of their own weight, and non-go-through gauges (NOT) should not pass through.
When checking with smooth gauges a number of rules must be followed, in particular, use only gauges intended for a given case (workers, as a rule, use new pass-through gauges, quality control workers can use partially worn gauges). It is necessary to ensure the cleanliness of the measuring surfaces, do not try to push through and no-go gauges by force, and in order to avoid heating, you should not hold the gauges in your hands longer than necessary.
The types of smooth non-adjustable gauges for monitoring cylindrical holes and shafts are established by GOST 24851-81, in which their various design types are assigned numbers (1...12) and corresponding names.
There are three versions of smooth calibers:
1. Single-limit plugs or staples (passing, marked PR, and non-passing - NOT), used primarily for the control of relatively large sizes.
2. Double-limit double-sided gauges, which speed up control somewhat. They are designed for relatively small sizes: staple gauges up to 10 mm and plug gauges up to 50 mm.
3. Single-sided double-limit gauges, which are more compact and almost double the speed of control. These gauges are available for a wide range of sizes.
Single sided staples, starting with sizes over 200 mm for control of shafts up to the 8th grade inclusive, must be equipped with heat-insulating handles-overlays.
Structurally smooth gauges can be made adjustable or non-adjustable.
Calibers for sizes over 500 mm, according to GOST 24852-81, are used only for testing parts of grades 9...17. These calibers have a uniform layout of tolerance fields.
The calculation of calibers comes down to determining the executive dimensions of the measuring surfaces, limiting the deviations of their shape and assigning the optimal roughness. The starting point for deviations for passing smooth gauges is the passing limit of the shaft or hole, for non-passing gauges - their non-passing limit. For pass-through gauges, in addition to the manufacturing permit, a permissible wear limit is also provided separately.
For efficient and accurate control of the internal dimensions of control gauges during their finishing during manufacturing and for quickly determining the moment of complete wear, smooth control gauges are used (Fig. 3.77 V).
The set of control gauges includes three gauges made in the form of washers:
Control pass gauge (K-PR);
Control no-go gauge (K-NOT);
Gauge for monitoring the wear of the pass-through gauge (CI).
Control gauges K-PR and K-NE, due to the small tolerances of the working calibers for which they are intended to control, are made as normal, rather than limiting calibers, and the suitability of the working calibers is determined using a subjective assessment of the compliance of the checked sizes with the control calibers.
The CI gauge is designed to control the permissible wear of the pass side and can be considered as a limit gauge that controls the limit of permissible wear.
Control gauges (for sizes up to 180 mm, you can also use gauge blocks) are designed to speed up checking the final dimensions of the pass and non-go sides when manufacturing non-adjustable or installing adjustable brackets (K-PR and K-NE), as well as to control the moment of complete wear of the pass-through staple gauges during their operation (CI).
Gauges for checking plug gauges are not manufactured. The dimensions of plug gauges are checked using universal measuring instruments, which is not difficult for external surfaces.
Manufacturing tolerances are established for all gauges, and for a pass gauge, which wears out more intensively when inspecting a part, a wear limit is additionally set.
Tolerances on the measuring surfaces of smooth gauges are established by GOST 24853-81 (for sizes up to 500 mm) and GOST 24852-81 (for sizes from 500 mm to 3150 mm). The tolerances of the working surfaces of the gauges are significantly less than the tolerances of the parts for which they are intended to control, and have been tested by many years of practice.
To construct diagrams of the location of tolerance fields, it is necessary to determine the nominal dimensions of the gauges, which correspond to the maximum dimensions of the hole or shaft surface controlled by the gauge (Fig. 3.78).
The location of the caliber tolerance fields according to GOST 24853-81 depends on the nominal size of the part (the schemes differ for sizes up to 180 mm and over 180 mm and for qualifications 6, 7, 8 and from 9 to 17).
Rice. 3.78. To determine the nominal sizes of calibers
The standard establishes the following standards for calibers:
- N - approval for the manufacture of gauges for holes;
- N s - approval for the manufacture of gauges with spherical measuring surfaces (for holes);
- N 1 - approval for the manufacture of shaft gauges;
- N r - approval for the manufacture of a control gauge for the staple.
The wear of pass-through gauges is limited to the following values:
-Y- permissible deviation of the size of a worn-out pass-through gauge for a hole beyond the tolerance zone of the product;
-Y 1 - the permissible deviation of the size of a worn pass-through gauge for a shaft beyond the tolerance range of the product.
For all pass gauges, the tolerance fields are shifted inside the tolerance field of the part by the amount Z for plug gauges and size Z 1 for clamp gauges. This arrangement of the tolerance field of a pass-through gauge, subject to wear, makes it possible to increase its durability, although it increases the risk of rejection of suitable parts by a new gauge.
Executive called the size of the gauge in which the caliber is made. When determining the executive size of a caliber, the nominal size is replaced: the maximum limit of the material of the caliber with the location of the tolerance field “into the body” of the part is taken as the “new” nominal size. In the drawings of working plug gauges and control gauges, the largest size with a negative deviation equal to the width of the tolerance field is indicated; for clamp gauges, the smallest size with a positive deviation.
Gauges are widely used for testing complex surfaces of parts, including spline and threaded surfaces. In this case, to design the working surfaces of calibers, the Taylor principle must be used.
For example, to control spline bushings, the working pass gauge is made in the form of a spline shaft, which allows you to simultaneously control the dimensions of the outer and inner diameters of the spline bushing, as well as the relative position of the outer and inner cylindrical surfaces of the bushing, the pitch and direction of the splines, and the width of the depressions. To control the no-go limits (limits for the minimum material of the part), a set of no-go gauges is used to check the actual dimensions of the spline bushing elements. The diameters are controlled by plugs, with an incomplete or full plug used for the internal diameter, and an incomplete plug used for the outer diameter of the spline bushing. The kit also includes a working gauge for checking the width of the slots.
For thread inspection use a working threaded plug with a full profile thread and a length equal to the length of the threaded connection. The set of no-go gauges includes a working no-go thread gauge with a shortened thread profile and reduced length of the threaded part, as well as smooth gauges for controlling the diameter of the protrusions. A no-go thread gauge should be screwed onto the mating piece by no more than one and a half turns.
Inspection of smooth cylindrical products such as shafts and bushings in mass and large-scale production is carried out using limit gauges (for products with sizes from 1 to 360 mm).
Calibers intended to determine the suitability of parts with approval from IT6 ... IT17.
Calibers are used to check the dimensions of smooth cylindrical, conical, threaded and splined parts, the depths and heights of protrusions, as well as the location of surfaces and other parameters.
To control the shafts, staple gauges are used, and plug gauges are used for holes.
It is impossible to determine the actual size of a part using gauges. With their help, they find out whether the size being tested is beyond the upper or lower limit, or is between them.
For control use set of calibers: passing (PR) and non-passing (NOT).
By purpose calibers are divided:
- workers – used by inspectors or workers when monitoring parts during their manufacturing process ( PR and NOT).
- control – when monitoring working calibers during their manufacture ( K-PR and K-NOT), and operation ( K-I wear). Manufactured only for staples in the form of rings. They are not made for plugs (complex configuration, high precision). K-I - control the maximum wear of the pass-through gauge.
Rules for using calibers
Detail considered fit, if the pass-through gauge (the pass-through side of the gauge), under the influence of its own weight or force approximately equal to it, passes, and the non-go-through gauge does not pass along the controlled surface of the part.
If the PR caliber does not pass, it is a correctable defect; FAILS – irreparable marriage.
Caliber designs
Plug gauges
Gauge gauges
Rigid and adjustable brackets are used. Adjustable brackets can be adjusted to different sizes (up to 330mm), allowing you to compensate for wear and use one bracket to control sizes within a certain range. Used to control sizes of grade 8 and coarser. Less accurate and less reliable compared to rigid ones.
Calibers, types and purpose. Control of macrogeometry parameters of parts using gauges
Calibers – measuring control tools designed to verify compliance of the actual dimensions, shape and location of the surfaces of parts with the specified requirements.
Gauges are used to control parts in mass and serial production. Calibers are normal and extreme.
Normal caliber– an unambiguous measure that reproduces the average value (the value of the middle of the tolerance field) of the controlled size. When using a normal gauge, the suitability of a part is judged, for example, by the gaps between the surfaces of the part and the gauge, or by the “density” of the resulting interface between the controlled part and the normal gauge. Gap assessment, therefore, control results largely depend on the qualifications of the inspector and are subjective.
Limit calibers– a measure or set of measures that ensures control of the geometric parameters of parts according to the highest and lowest limit values. Limit gauges are made to check the dimensions of smooth cylindrical and conical surfaces, the depth and height of ledges, and the parameters of threaded and splined surfaces of parts. Gauges are also made to control the location of surfaces of parts, standardized by positional tolerances, alignment tolerances, etc.
When testing by limit gauges, a part is considered suitable if the pass gauge passes under the influence of gravity, and the non-go gauge does not pass through the controlled element of the part. The control results are practically independent of the operator’s qualifications.
By design, calibers are divided into plugs and staples. To control holes, plug gauges are used, and to control shafts, clamp gauges are used.
By purpose, calibers are divided into workers and control .
Workers gauges are designed to control parts during their manufacturing and acceptance. Such calibers are used at enterprises by workers and inspectors of technical control departments (QCD). Tests gauges are used to control rigid working limit gauges or to adjust adjustable working gauges.
A set of working limit gauges for testing smooth cylindrical surfaces of parts includes:
· bore gauge (PR), the nominal size of which is equal to the largest maximum shaft size or the smallest maximum hole size;
· no-go gauge (NOT), the nominal size of which is equal to the smallest maximum shaft size or the largest maximum hole size.
The design of smooth gauges is based on the Taylor principle or the principle of similarity, according to which the passage gauges should be a prototype of the mating part and comprehensively control all types of errors of a given surface (checking the diameter and shape errors, including deviations from the straightness of the hole axis). This ensures the assembly of the connection. Non-go gauges must provide element-by-element control (control of the actual dimensions), therefore, the contact between the working surfaces of the gauges and the controlled surface must be point-like.
A working gauge that fully complies with the Taylor principle for checking a hole must have a pass-through side in the form of a cylinder with a length equal to the length of the mating or controlled surface (full plug), and a non-pass-through side in the form of an incomplete plug in the form of a rod with spherical tips. The working gauge for shaft control must have a pass side in the form of a ring with a length equal to the length of the mating or controlled surface, and a non-pass side in the form of a bracket with knife surfaces. In practice, due to the peculiarities of manufacturing and control technology, a violation of the Taylor principle is often observed; for example, gauges for testing small diameter holes are made in the form of full plugs, and for testing shafts - in the form of brackets.
Control of hole sizes is usually carried out with go-through and no-go plug gauges inserted into a common handle (Fig. 3.77 A).
Shaft gauges are usually made in the form of brackets with plane-parallel working surfaces (Fig. 3.77 b).
b | V |
Rice. 3.77. Sketches of calibers
If the go and no-go gauges for checking holes are made in the form of full plugs, then the no-go plug has a shorter length than the go-through one. For holes of large diameters, gauges with working surfaces in the form of an incomplete plug are more often used, for example, a sheet plug with cylindrical working surfaces, and the length of the working surfaces of a non-go-through plug is significantly less than that of a go-through plug. Each plug controls several cross sections of the hole (at least two mutually perpendicular sections are controlled).
When inspecting shafts with a clamp gauge, the surface is checked in several sections along the length and in at least two mutually perpendicular directions of each section.
If the parts are suitable, then, in accordance with the name, go-through gauges (PG) should pass through the controlled surfaces under the influence of their own weight, and non-go-through gauges (NOT) should not pass through.
When inspecting smooth gauges, a number of rules must be followed, in particular, use only gauges intended for this case (workers, as a rule, use new pass gauges, quality control workers can use partially worn gauges). It is necessary to ensure the cleanliness of the measuring surfaces, do not try to push through and no-go gauges by force, and in order to avoid heating, you should not hold the gauges in your hands for longer than is absolutely necessary.
The types of smooth non-adjustable gauges for monitoring cylindrical holes and shafts are established by GOST 24851-81, in which their various design types are assigned numbers (1...12) and corresponding names.
There are three versions of smooth calibers:
1. Single-limit plugs or staples (passing, marked PR, and non-passing - NOT), used primarily for the control of relatively large sizes.
2. Double-limit double-sided gauges, which speed up control somewhat. They are designed for relatively small sizes: staple gauges up to 10 mm and plug gauges up to 50 mm.
3. Single-sided double-limit gauges, which are more compact and almost double the speed of control. These gauges are available for a wide range of sizes.
Single-sided staples, starting with sizes over 200 mm for controlling shafts up to the 8th grade inclusive, must be equipped with heat-insulating handles.
Structurally smooth gauges can be made adjustable or non-adjustable.
Calibers for sizes over 500 mm, according to GOST 24852-81, are used only for testing parts of grades 9...17. These calibers have a uniform layout of tolerance fields.
Calculation of calibers comes down to determining the executive dimensions of measuring surfaces, limiting deviations in their shape and assigning optimal roughness. The starting point for deviations for passing smooth gauges is the passing limit of the shaft or hole, for non-passing gauges - their non-passing limit. For pass-through gauges, in addition to the manufacturing permit, a permissible wear limit is also provided separately.
For productive and accurate control of the internal dimensions of the control gauges during the process of finishing them during manufacturing and for quickly determining the moment of complete wear, smooth control gauges are used (Fig. 3.77 V).
The set of control gauges includes three gauges made in the form of washers
· control passage gauge (K-PR);
· control no-go gauge (K-NOT);
· gauge for monitoring the wear of the pass-through gauge (CI).
The control calibers K-PR and K-NE, due to the small tolerances of the working calibers for which they are intended to control, are made as normal, and not limiting calibers, and the suitability of the working calibers is determined using a subjective assessment of the compliance of the checked sizes with the control calibers.
The CI gauge is designed to control the permissible wear of the pass side and can be considered as a limit gauge that controls the limit of permissible wear.
Control gauges (for sizes up to 180 mm, you can also use gauge blocks) are designed to speed up checking the final dimensions of the pass and non-go sides when manufacturing non-adjustable or installing adjustable brackets (K-PR and K-NE), as well as to control the moment of complete wear of the pass-through staple gauges during their operation (CI).
Gauges for checking plug gauges are not manufactured. The dimensions of plug gauges are checked using universal measuring instruments, which is not difficult for external surfaces.
Manufacturing tolerances are established for all gauges, and for a pass gauge, which wears out more intensively when inspecting a part, a wear limit is additionally set.
Tolerances on the measuring surfaces of smooth gauges are established by GOST 24853-81 (for sizes up to 500 mm) and GOST 24852-81 (for sizes from 500 mm to 3150 mm). The tolerances of the working surfaces of the gauges are significantly less than the tolerances of the parts for which they are intended to control, and have been tested by many years of practice.
To construct layout diagrams of tolerance fields, it is extremely important to determine the nominal dimensions of the gauges, which correspond to the maximum dimensions of the surface of the hole or shaft controlled by the gauge (Fig. 3.78).
The location of the caliber tolerance fields according to GOST 24853-81 depends on the nominal size of the part (the schemes differ for sizes up to 180 mm and over 180 mm and for qualifications 6, 7, 8 and from 9 to 17).
Rice. 3.78. To determine the nominal sizes of calibers
The standard establishes the following standards for calibers:
· N – approval for the manufacture of gauges for holes;
· N s – approval for the manufacture of gauges with spherical measuring surfaces (for holes);
· N 1 – approval for the manufacture of shaft gauges;
· N r – approval for the manufacture of a control gauge for the staple.
The wear of pass-through gauges is limited to the following values:
· Y – permissible deviation of the size of a worn-out pass-through gauge for a hole beyond the tolerance zone of the product;
· Y 1 – the permissible deviation of the size of a worn pass-through gauge for a shaft beyond the tolerance range of the product.
For all pass gauges, the tolerance fields are shifted inside the tolerance field of the part by the amount Z for plug gauges and size Z 1 for clamp gauges. This arrangement of the tolerance field of a pass-through gauge, subject to wear, makes it possible to increase its durability, although it increases the risk of rejection of suitable parts by a new gauge.
Executive It is customary to call the size of the caliber by which the caliber is made.
Posted on ref.rf
When determining the executive size of a caliber, the nominal size is replaced: the maximum limit of the caliber material with the location of the tolerance field “into the body” of the part is taken as the “new” nominal size. In the drawings of working plug gauges and control gauges, the largest size with a negative deviation equal to the width of the tolerance field is indicated; for clamp gauges, the smallest size with a positive deviation.
Gauges are widely used for testing complex surfaces of parts, including spline and threaded surfaces. In this case, to design the working surfaces of calibers, the Taylor principle must be used.
For example, to control spline bushings, the working pass gauge is made in the form of a spline shaft, which allows you to simultaneously control the dimensions of the outer and inner diameters of the spline bushing, as well as the relative position of the outer and inner cylindrical surfaces of the bushing, the pitch and direction of the splines, and the width of the depressions. To control the no-go limits (limits for the minimum material of the part), a set of no-go gauges is used to check the actual dimensions of the spline bushing elements. The diameters are controlled by plugs, with an incomplete or full plug used for the internal diameter, and an incomplete plug used for the outer diameter of the spline bushing. The kit also includes a working gauge for checking the width of the slots.
To control the thread, use a working threaded plug with a full profile thread and a length equal to the length of the threaded mate. The set of no-go gauges includes a working no-go thread gauge with a shortened thread profile and reduced length of the threaded part, as well as smooth gauges for controlling the diameter of the protrusions. A no-go thread gauge should be screwed onto the mating piece by no more than one and a half turns.
Calibers, types and purpose. Control of macrogeometry parameters of parts using gauges - concept and types. Classification and features of the category "Gauges, types and purpose. Control of macrogeometry parameters of parts using gauges" 2017, 2018.
They are called calibers scale-free measures that are designed to control the size, shape and location of the surfaces of parts. According to the control method, calibers are divided into normal and limit. Normal calibers copy the size and shape of products.
Limit gauges reproduce dimensions corresponding to the upper and lower tolerance limits of the product. During control, pass-through and non-pass-through are used. maximum calibers. By design, limit gauges are divided into unregulated and adjustable. Adjustable gauges allow you to compensate for their wear or set the caliber to a different size; limit gauges can be single-limit and double-limit, combining pass and no-go gauges. Both limit gauges can be located on the same side. In this case, the limiting gauges are called one-sided.
Complex calibers(Fig. 1.26) are designed to control several product dimensions (for example, spline joint parts).
Differential gauges (Fig. 1.27) allow you to control only one size (for example, a gauge for controlling the width of a keyway).
According to their purpose, working gauges are distinguished to control products during manufacturing; inspector calibers (for checking products by technical control service workers); receiving gauges for control of products by the customer; control gauges for checking the sizes of working and receiving gauges. Partially worn pass-through and unworn non-pass-through gauges are used as the controller gauge.
The gauges are marked with markings indicating the parameters of the parts being controlled: nominal size, tolerance zone designation and maximum deviations.
Normal caliber templates(Fig. 1.28) are used to control the size and shape of products with complex profiles. Templates 1 can be applied to the tested profile of product 2 (Fig. 1.28, a) or applied to product 2 with the profiles aligned (Fig. 1.28, b). In the first case, the deviation of the product profile from the template profile is determined by “paint” if the deviation is less than 3 µm, or by transmission if the deviation is more than 3 µm. When testing for “paint,” the surface of the template is covered with a thin layer of paint and applied to the product. The print of the paint on the surface of the product being tested is used to judge the tightness of the template.
When inspecting a product by combining profiles, the deviation of the profile is determined using an indicator (see Fig. 1.28, b). The indicator is used in cases where the deviation is no more than 5 microns upward or downward; if this value is greater, then the deviation is assessed visually.
To determine radii of curvatures from 1 to 25 mm, radius templates are used (Fig. 1.29), which are steel plates with a circular arc profile of the corresponding radius. They are assembled in sets consisting of plates with 1 convex or 3 concave profiles. The plates are assembled into a holder 2. During inspection, radius templates are usually applied to the product profile. If there is no gap in the mate, then the radii of the product and the template are equal.
Probes
A fairly common tool are probes, which are a set of plates of a certain thickness (Fig. 1.30). The probes are normal gauges when checking the gaps between surfaces, they are produced with nominal sizes of 0.02 ... 1.0 mm, with gradations of 0.01 and 0.05 mm. The length of the probes is divided into two versions: 200 and 100 mm. Probes with a length of 100 mm are manufactured both in the form of individual plates and in the form of sets, and with a length of 200 mm - only in the form of individual plates. When measuring the gap, a feeler gauge or set of feeler gauges is inserted into it. When measuring, the probe should move in the gap with little force, i.e. it should not fall into the gap and move freely.
When measuring gaps with a feeler gauge, a number of rules should be followed:
Before measuring the gap, make sure that the feeler plates move smoothly;
If the movement of the plates in the gap is difficult, then they should be lightly lubricated;
The size of the gap is determined by the total size of the set of probe plates that are completely included in the gap along its entire length;
When measuring the gap, do not apply great force to the feeler gauge to avoid breaking the plates or deforming them.
Gauge-staples
The most common limit calibers are gauge-staples for checking smooth shafts and a plug gauge for checking smooth holes.
Gauge staples have different designs(Fig. 1.31). They are made single- and double-sided from sheet material (Fig. 1.31, c, b). Such brackets are used for shafts with a diameter from 1 to 500 mm. To control shafts with a diameter of 3 to 100 mm, staples made from stamped blanks are used. Such staples have increased wear resistance and durability.
Stamped brackets are made, as a rule, one-sided (Fig. 1.31, c), and also with replaceable measuring jaws (Fig. 1.31, d).
The increased durability of these staples compared to staples made from sheet metal is due to their increased rigidity and wider measuring surface.
Gauge plugs
Gauge plugs to control holes of small diameter (1 ... 3 mm), they are made double-sided with inserts made of calibrated wire (Fig. 1.32, a).
Double-sided gauge plugs, having inserts with conical shanks (Fig. 1.32, b), are used to control holes with a diameter of 3 to 50 mm. The length of the pass-through gauge for these plugs is greater than the length of the non-go-through gauge. For the same sizes, one-sided plugs are sometimes used, in which the go and no-go gauges are located on one side of the handle, however, such plugs are difficult to manufacture and do not allow control of shallow blind and long holes, so they are rarely used.
To control holes with a diameter of 50 to 100 mm, double-sided plugs with nozzles (Fig. 1.32, c) having a full profile are used. The use of such gauges is difficult due to their large mass, therefore, when checking large-diameter holes, plugs with incomplete profiles are often used. Gauge plugs with an incomplete profile are made double-sided from sheet blanks; they are used to control holes with sizes from 50 to 250 mm. Caliber plugs with an incomplete profile can also be made one-sided.
Control of holes with a diameter from 250 to 1000 mm is carried out using limit gauges or pin gauges. For bore gauges, the measuring surfaces are cylindrical, and for bore gauges, they are spherical. Calipers and bore gauges are used in the form of sets consisting of two gauges—go and no-go.
To check the outer diameters of parts manufactured to tolerances, limit gauges are used.
Limit brackets
When measuring the outer diameter of a part (Fig. 59), the pass-through side of the bracket should easily fit onto the part being measured under its own weight, and the non-pass-through side should not touch it.
Rice. 59 Checking the outer diameter with a double-sided limit bracket
If the bead being measured extends to the larger side of the bracket, then its size does not exceed the permissible limit, and if not, then its size is too large. If the roller also extends to the smaller side of the bracket, then this means that its diameter is too small, i.e., less than permissible - such a roller is a defect.
Single sided staples
Figure 60. Single-sided limit bracket
To measure large-diameter shafts, instead of double-sided clamps, single-sided clamps are used (Fig. 60), in which both pairs of measuring surfaces are located one behind the other. The front measuring surfaces of such a bracket are used to check the largest permissible diameter of the part, and the rear ones are used to check the smallest.
These clamps have less weight and significantly speed up the inspection process, since for measurement it is enough to apply the clamp once to the part being tested.
Adjustable brackets
Rice. 61. Adjustable limit bracket
In Fig. Figure 61 shows the adjustable limit bracket. When these brackets become worn, the correct dimensions can be restored by rearranging the measuring pins. In addition, they can be adjusted to specific dimensions so that a large number of dimensions can be checked with a small set of staples.
To change to a new size, you need to loosen the locking screws 1 on the left jaw, move the measuring pins 2 and 3 accordingly and secure the screws 1 again.