The project "fitting and sawing." General information about plumbing
Fitting is the mutual fitting of one part to another without gaps, swings and distortions.
The hole of one of the fittings is called the armhole, and the other fitment part included in the armhole is called an insert.
Fitting parts by filing is a difficult job, it requires patience and perseverance.
Fit with special, - files. The fitted parts must fit one into the other freely. Such requirements impose on many parts of machines. The sharp ribs and corners of the sawed surfaces of the parts are most hindering the fitting.
Blunting sharp edges, (smoothing) cannot be mixed with chamfering. When chamfering on a rib, parts make a flat surface of certain sizes, according to the drawing, while blunting is limited to smoothing sharp ribs and deburring.
Control the prepared surfaces for clearance, as well as using special plates (probes). If the connected parts are not visible in the lumen, they are sawed over with paint.
Having covered one surface with a thin layer of paint, impose on it another surface of the mating part. Traces (spots from paint) show that it is these places that interfere with the movement of one part over another.
The spots are removed with a file and so repeated until the adjustable surface is completely painted. Usually on adjustable surfaces and without paint, they distinguish traces (in the form of shiny spots) from the friction of one surface against another.
Questions
- What is fitting parts?
- What is called armhole?
- What is an insert?
- Why fit parts?
- What are the requirements for fitting?
- How to check fittings?
Fit most often in the manufacture of templates and counter-patterns. A template is a tool that controls the profile by the "light gap". Check pattern check templates.
The following describes the manufacture of the template (armhole), shown in the figure below.
a - drawing; 6, c and d are the processing sequence.
A rectangular blank 82 mm long and 45 mm high (82X45 mm) is cut from sheet steel 3 mm thick. They clean and cover one wide surface with a solution of copper sulfate. They saw a narrow surface, it serves as a basis for marking.
Then mark up the template. After drilling (or cutting with a hacksaw), the armholes of the template file the contours in a certain sequence. Precisely filed side 3 parallel to side 1 and sides 2 and 4, checking them with a ruler and a square. The pattern is treated with a semicircular or round file.
When sawing openings, open circuits and holes, the following rules must be observed:
1. It is rational to determine the method of preliminary formation of sawn openings and holes: in parts with a thickness of up to 5 mm - by cutting, and in parts with a thickness of more than 5 mm - by drilling or reaming, followed by cutting or cutting the jumpers.
2. When drilling, drilling, cutting or cutting out jumpers, it is necessary to strictly monitor the integrity of the marking marks, leaving an allowance for processing of about 1 mm.
3. A rational sequence of processing openings and holes should be observed: first, process straight sections of surfaces, and then curved sections associated with them.
4. The process of sawing openings and holes must be periodically combined with checking their contours according to a control template, insert or workout.
5. The corners of the openings or holes must be finished clean with a file edge of the corresponding cross-sectional profile (No. 3 or 4) or files, checking the quality of processing with workings.
6. Finishing the surface of the holes should be done with a longitudinal stroke.
7. For the final calibration and finish of the hole, use notches, broaches and firmware on a screw or pneumatic press (Fig. 4.2).
8. The work should be considered completed when the control template or insert completely, without pitching, enters the opening or hole, and the clearance (gap) between the template (insert, output) and the sides of the contour of the opening (hole) is uniform.
Fit rules
When fitting The following rules must be observed:
1. The fitting of two parts (pairs) to each other should be carried out in the following order: first, one part of the pair is made and finished (usually with external contours) - the liner, and then another, paired according to the template, is fitted and fitted (fitted) detail - armhole.
2. The quality of the fit should be checked by the clearance: in the gap between the parts of the pair, the clearance should be uniform.
3. If the contour of a pair of parts - the liner and the armhole - is symmetrical, they should be mated effortlessly with a uniform gap when turning 180 °.
Typical defects during sawing and fitting parts, the reasons for their appearance and methods of prevention are given in table. 4.1.
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Table 4.1 Typical defects during sawing and fitting parts, the reasons for their appearance and methods of prevention
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The end of the table. 4.1
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Fitting is the mutual fit of two parts that mate without clearance. Fit both closed and semi-closed circuits. The fit is characterized by high precision machining. Of the two fittings, the hole is called the armhole, and the part entering the armhole is called the insert.
In the manufacture and fitting of templates with a semicircular outer and inner contour, a part with an inner contour is first produced - an armhole (Fig. 151, d). An insert is fitted to the treated armhole.
Processing armholes are in the following order. First, wide planes are precisely filed as base surfaces, then rough - edges 1; 2; 3 and 4, after which they mark a semicircle with a pair of compasses, cut it with a hacksaw (as shown by the dotted line in the figure); make accurate filing of a semicircular recess and check the accuracy of processing according to the template, as well as for symmetry with respect to the axis using a caliper.
When processing the liner, first saw off wide surfaces, and then the ribs 1, 2 and 3. Next, mark the corners and cut them with a hacksaw. After this, the exact filing and fitting of the ribs 5 to 6. is performed. Then, the exact filing and fitting of the insert to the armhole is performed. The accuracy of the fit is considered sufficient if the insert enters the armhole without skewing, pitching and gaps.
In the manufacture and fitting of oblique liners and dovetail armholes depicted in Fig. 151, d, the liner is first processed (processing and verification is easier).
The liner is processed in the following order. First, wide planes are precisely filed as base surfaces, then all four narrow ribs 1, 2, 3 and 4. Next, sharp edges are marked, cut with a hacksaw and precisely filed. First, ribs 5 and 6 are filed in a plane parallel to rib 7, then ribs 7 and 8 in a ruler and at an angle of 60 ° to rib 4. An acute angle (60 °) is measured with an angular gauge.
Next, marking, cutting a groove with a hacksaw (dotted line in the figure) and filing of the ribs 5; 6 and 7. First, the groove width is made less than the required one by 0.05-0.1 mm while maintaining strict symmetry of the side ribs of the groove with respect to the axis of the armhole, while the depth of the groove is immediately accurate in size. Then, when fitting the liner and armhole, the width of the groove gets the exact size in the shape of the protrusion of the liner. The accuracy of fitting is considered sufficient if the insert enters the armhole tight by hand, without gaps, pitching and distortions.
The filing prism (Fig. 152, a) consists of two plates 1 with guides 2 and 3. The side surface of the plate has threaded holes 7 for bolting the clamping plate 4, rectangle 5 and ruler 6. Procurement of all four narrow ribs 1, 2, 3 and 4. Next, sharp edges are marked, cut with a hacksaw and precisely filed. First, ribs 5 and 6 are filed in a plane parallel to rib 7, then ribs 7 and 8 in a ruler and at an angle of 60 ° to rib 4. An acute angle (60 °) is measured with an angular gauge.
Fig. 152. Filing prism (a), filing reception (b)
The armhole is processed in the following order. First, broad planes are precisely filed, after which all four ribs are filed.
Next, marking, cutting a groove with a hacksaw (dotted line in the figure) and filing of the ribs 5; 6 and 7. First, the groove width is made less than the required one by 0.05-0.1 mm while maintaining strict symmetry of the side ribs of the groove with respect to the axis of the armhole, while the depth of the groove is immediately accurate in size. Then, when fitting the liner and armhole, the width of the groove gets the exact size in the shape of the protrusion of the liner. The accuracy of fitting is considered sufficient if the insert enters the armhole tight by hand, without gaps, pitching and distortions.
Using special tools and devices, they achieve increased sawing and fitting performance. These tools and fixtures include hand files with interchangeable plates and wire files coated with diamond chips, filing prisms, filing basting, etc.
A hand file with interchangeable plates has a case made of light alloy, in which interchangeable inserts made of high-quality carbon steel are firmly fixed. The plates have notches. Under each tooth there is a hole through which the removed chips are forced, which protects the teeth from clogging.
This file is used for processing steel, aluminum, copper, as well as wood, leather, rubber and other materials. After wear, the plates are changed. Experience has shown that a prefabricated file is significantly more productive than usual.
The filing prism (Fig. 152, a) consists of two plates 1 with guides 2 and 3. The side surface of the plate has threaded holes 7 for bolting the clamping plate 4, rectangle 5 and ruler 6. The blank is installed between the guides 2 and 3 so that the metal layer to be removed protruded above the planes of the guides, and is firmly fixed with a clamping bar 4. The prism is fixed in a bench vise (Fig. 152, b). Squares 5 and a ruler 6 are used to verify the installation of the workpiece.
The sliding frame is a kind of filing prism and has the same purpose. It consists of two rectangular metal bars having grooves at the edges, which include two guide bars connecting these bars.
The rectangular block is tightly screwed to one end of the guide rails. Such a device allows the installation in a sliding frame of workpieces of different sizes (within the length of the guide rails).
The frame is installed in a bench vise, after which the workpiece is clamped in it, which is then filed.
Self Test Questions
- What are the features, techniques and rules of fitting?
- How is sawing and fitting of trihedral holes?
- What tools are used for sawing and fitting?
Fit is the processing of one part over another in order to make the connection. For fitting, it is necessary that one of the parts is completely ready, fit is carried out along it. Fit is widely used in repair work, as well as in the assembly of individual products.
File fitting is one of the most difficult work of a locksmith, as it has to be processed in hard-to-reach places. It is advisable to perform this operation with boron files, grinding borogolovki, using filing and cleaning machines.
When fitting the liner to the finished hole, the work is reduced to the usual filing. When fitting over a large number of surfaces, two conjugated base sides are first treated, then the other two are adjusted to obtain the desired mating. Parts must enter one another without pitching, freely. If the product is not visible through the lumen, they are sawed over the paint.
Sometimes on customized surfaces and without paint, you can distinguish traces from the friction of one surface on another. Traces that look like shiny spots ("fireflies") show that this place interferes with the movement of one part over another. These places (protrusions) are removed, achieving either a lack of brilliance or a uniform brilliance over the entire surface.
For any fitting work, sharp edges and burrs cannot be left on the parts; they must be smoothed out with a personal file. How well the edge is smoothed can be determined by drawing a finger over it.
Fitting is the exact mutual fit of parts that connect without gaps in any rifling. The fitting is characterized by high processing accuracy, which is necessary for gapless pairing of parts (a light gap of more than 0.002 mm is visible).
Fit both closed and semi-closed circuits. Of the two fittings, the hole is called the armhole, and the part entering the armhole is called the insert.
Armholes are open (Fig. 336) and closed (see Fig. 335). The fit is done with files with small and very small notches - No. 2, 3, 4 and 5, as well as abrasive powders and pastes.
In the manufacture and fitting of templates with semicircular external and internal contours, a part with an internal contour is first produced - an armhole (1st operation) (Fig. 336, a). An insert is fitted (fitted) to the treated armhole (Fig. 336.6) (2nd operation).
When processing the armholes, they first precisely cut wide planes as base surfaces, then rough ribs (narrow edges) 1,2,3 and 4, after which they draw a semicircle with a pair of compasses and cut it with a hacksaw (as shown by a prime in the figure); make accurate filing of the semicircular recess (Fig. 336, c) and check the accuracy of the processing by the liner, as well as the symmetry with respect to the axis using a caliper.
When processing the liner, first saw off wide surfaces, and then the ribs 1, 2 and 3. Next, mark the corners and cut them with a hacksaw. After that, the exact filing and fitting of the ribs 5 and 6 is performed. Then, the exact filing and fitting of the insert to the armhole is performed. The accuracy of fitting is considered sufficient if the insert enters the armhole without skewing, pitching and gaps (Fig. 336, d).
In the manufacture and fitting of oblique dovetail inserts and armholes (Fig. 337, h, 6), I first process the * - insert (processing and checking it is easier). Processing is carried out in the following order (Fig. 337.6). First, wide planes are precisely filed as base surfaces, then all four narrow faces (edges) 1, 2, 3 and 4. Next, sharp edges are marked (Fig. 337, c), cut with a hacksaw and precisely filed. First saw ribs 5 and 6 (Fig. 337, c, d) in a plane parallel to rib 7, then ribs 7 and 8 (Fig. 337, a) in a ruler and at an angle of 60 ° to edge 4. An acute angle (60 ° ) measure with an angular gauge.
The armhole is processed in the following order. At first, wide planes are precisely filed, after which all four ribs are filed.
Next, marking, cutting a groove with a hacksaw (shown in Fig. 337, shown by a dash) and filing of the ribs 5, 6 and 7. First, the groove width is made less than the required one by 0.05 - 0.1 mm while maintaining the strict symmetry of the side ribs of the groove with respect to to the axis of the armhole, the depth of the groove is immediately accurate in size. Then, when fitting the liner and armhole, the width of the groove gets the exact size in the shape of the protrusion of the liner. The accuracy of fitting is considered sufficient if the insert enters the armhole tight by hand, without gaps, pitching and distortions (Fig. 337, e).
Manual sawing, fitting and fitting are very laborious operations. In modern conditions, these operations are performed using metal-cutting equipment of general and special purpose, in which the role of a locksmith is reduced to machine control and size control.
Curved and shaped parts are processed on grinding machines with special profiled abrasive wheels. Electrospark, chemical and other processing methods that exclude additional manual finishing are also widely used.
However, when performing fitter's and assembly, repair work, as well as during the final processing of parts obtained by stamping, it is necessary to perform these works manually.
Using special tools and devices, they achieve increased sawing and fitting performance. These tools and fixtures include hand files with interchangeable plates and wire files coated with diamond chips, filing prisms, filing basting, etc.
TO category:
Metal cutting
The essence of sawing and fitting
In the practice of metalwork, sawing and fitting processes are quite common, especially when performing repair and assembly work, as well as in tool shops of machine-building plants.
The essence of the sawing process is that by processing round holes with files of various profiles, square, rectangular, oval and other shapes are obtained.
In some cases, blanks of machine parts and products with holes of the desired shape are also obtained by stamping, however, their final processing is also carried out by files by sawing according to the sizes indicated on the drawings. In order not to damage the walls of the hole being sawn by the lateral edges of the file, its cross section should be smaller than the size of the hole. Sawing holes in parts with narrow, flat and straight surfaces is done using basting, frames and parallels.
Fitting - the final exact fit of one part to another without any gaps, swings and distortions. In this case, one of the parts before fitting and fitting must be processed within the specified accuracy.
Templates, counter patterns, dies and punches of punches are subjected to storage, etc. For the template and counter pattern, the working parts must be fitted very precisely so that when connecting the fitted sides of the template and the counter pattern, there will be no gap between them at any possible mutual permutations.
Make fit both closed (closed) and semi-closed (open) circuits. These contour cavities (holes) are called armhole m and.
The correctness of their contours is checked by special gauge gauges called workings.
File sawing and fitting are very labor-intensive manual processes; where possible, they try to mechanize them.