DIY lathe repair

In detail: do-it-yourself repair of lathes from a real master for the site my.housecope.com.

During the overhaul of the lathe, the accuracy of the bed guides is restored. When choosing a restoration method, they are guided by the degree of their wear. When the error does not exceed 0.15 mm over a length of 1000 mm, then they are restored by scraping. With greater wear, they resort to mechanical processing: grinding or planing. When the guides are hardened, the main repair method is grinding.

Scraping of guides or scraping with subsequent lapping is still the most effective way to restore their geometric, technical accuracy. And now this method is often used, for many decades, demonstrating an excellent result of the repair of the bed. First of all, it is necessary to inspect the condition of the guides, to determine the degree of their wear. The place where the wear is minimal is taken as the base level, and the measurement data are entered into the table, on the basis of which the repair will be carried out. In a lathe, the location of the tailstock is most often taken as the base surface, which practically does not wear out during the operation of the equipment. The method includes the following steps:

installation of the machine bed on a rigid base (repair stand), the longitudinal and transverse position of the bed should be set exactly in the horizontal plane with wedges, shoes or using jacks;
after the completion of the preparatory work, a rough (preliminary) scraping is performed with a scraper working width of 20-25 mm, while the length of the strokes on the surface of more than 10 mm is maintained and 4-6 spots are achieved when testing for paint in squares of 25 × 25 mm. This achieves a breakdown of large spots into smaller ones;
semi-finishing scraping is performed with a 12-16 mm scraper, strokes 5-10 mm long until 8-15 spots per square are reached;
finishing (finishing) scraping is performed with a scraper 5-10 mm wide and 3-5 mm strokes long to achieve 20-25 spots in a square.

Video (click to play).

Since the guides of the lathe bed are quite long, processing is carried out according to beacons with a breakdown of the total length into sections. The first beacon is always the place of maximum production. At a distance less than the length of the straightedge, the second beacon, located in the same plane with the first, is scraped from the first beacon. Then the entire surface between the beacons is scrubbed, followed by a transition to an adjacent area. A ruler with paint should be applied periodically to assess the condition of the guides and the quality of work.

Watch the video of rough scraping

The unhardened parts of the lathe guides are subjected to such processing, the method guarantees the achievement of a high surface accuracy (0.002 mm per 1000 mm length). Formed after scraping, the smallest holes are able to hold well and evenly distribute the lubricant. The quality of scraping depends entirely on the professionalism of the worker.

It is not always possible to use continuous planing or longitudinal milling machines for repairs due to the large length of the lathe bed. In this case, the bed guides are restored using a portable device with a grinding head, which is installed directly on the equipment bed.

Repairs can be carried out on site, without removing the machine from the foundation. This method provides high accuracy of repair, low surface roughness, it is also indispensable when processing a hardened surface.This method is many times superior in productivity to scraping, but experts still prefer finishing planing. Image - DIY lathe repair

This method is less tedious than scraping and less expensive sanding. For example, the average repair time for machine guides is:

scraping: about 35 hours;
by grinding with a special abrasive head: 8-10 hours;
finishing planing: 4-5 hours.

When wear is more than 0.15 mm, manual scraping is replaced by machining on a planer with a centralized method of organizing repairs in a repair shop or at a specialized enterprise. The reason is simple, you will have to remove the bed from the foundation and carry out installation and alignment on the rigid table of the planer.

Planing bed guides

At the first stage, a test planing is performed once to obtain a base surface, which will allow determining the deviations along the entire length of the bed. To do this, the cutter is alternately brought to the most worn surfaces and the metal layer is removed until the wear is eliminated. Finish planing is carried out in at least two passes with fine wide carbide cutters. The last pass is performed with a cutting depth of less than 0.05 mm, constantly wetting the cutter and the surface of the guides with kerosene. When the wear exceeds 0.4-0.5 mm, the guides are subjected to rough and fine planing. The main disadvantage of this repair method is the considerable time spent on dismantling the bed, transporting it, installing the bed on the planer table, aligning and removing the restored bed.

When machining by cutting a flat prismatic surface of the guides, tiny metal particles of various sizes and shapes are pulled out of the bed solid. Furrows, grooves appear on the surface, forming a rough surface. Therefore, sometimes after machining, scraping or vibration rolling is indispensable. This increases the strength of the guides due to plastic deformation (changes in the structure of the material). Vibration rolls achieve smoothing of microroughnesses and irregularities by translational movement along and across the axis with specially processed balls or rollers.

Repair of lathe guides by one of the described methods is an element of complex work related to the restoration of full operability and accuracy of metal-cutting equipment. But do not forget that the quality of repairs with a minimum period of its implementation depends significantly on the degree of preparation of the machine for repair and the qualifications of the locksmith.If you find an error, please select a piece of text and press Ctrl + Enter.Scribing machine guides is one of the most effective ways to restore the geometric and technical parameters of a given unit of turning and other units. It is used very often and has shown excellent repair results.Any specialist knows that the implementation of repairs of machines used in various enterprises, according to a schedule drawn up in advance, is considered a very important procedure. When carrying out scheduled repairs, various mechanisms of the processing units are restored, including the guide beds.Also, the restoration of the guides may be required outside of the schedule if they require immediate repair. The amount of their wear is determined by a special method, which we will describe. Inspection of the condition of the guides is carried out using probes and a control ruler. The length of the latter is always chosen so that it is at least 2/3 of the extent of the surface to be checked. Image - DIY lathe repair

The scheme for establishing the amount of wear is as follows:

the surface of the node of interest to us is cleaned in order to remove serious seizures and nicks from it;
the ruler is placed on the guide and the gap between them is measured using the probes (measurements are taken every 30-50 centimeters along the entire length of the machine element).

The place where the gap is maximized is defined as the area where there is a maximum change in the straightness of the guide (that is, there is obvious wear). Next, the next stage of verification is carried out, which makes it possible to establish the flatness of the guide. This is done like this:

a ruler is placed on tiles of the same geometric parameters;
with the help of probes, the distance between the measuring tool and the investigated surface is determined.

A similar operation is performed at 2-3 points along the length, and in different directions. Experienced technicians make verification even easier. They take small sheets of very thin paper (for example, cigarette paper, the thickness of which does not exceed 0.02 millimeters), lay them on guides in several areas, and then press them with a ruler.

Further, from under the measuring device, these leaves are pulled out one by one. When the straightness of the part is not violated, you can only break off the ends of the pieces of paper, but not pull them out. The condition of the horizontal guides is verified using a level and a bridge:

they are placed on that part of the frame that visually seems to be as worn out as possible (in such a section, the bubble in the level will deviate in different directions at approximately the same distance);
moving the measuring instruments to the adjacent zone, where the deviation of the bubble is noted, entering the reading in the graph-table;
then move the bridge further and again record the result obtained.

Based on the table, it is subsequently easy to determine where exactly the wear occurred.

The bed is placed on a hard floor covering or on a special stand, after which it is examined according to the level in the longitudinal direction (the above-described check is carried out), and then in the transverse direction. Using wedges or shoes, they adjust the position of the bed as accurately as possible.It can also be placed on the jack bolts. In this case, the adjustment of the position of the bed will be very simple, you just need to lower or raise it by screwing or unscrewing the bolts. The operation of giving the bed the correct position is continued until the bubble in the level is fixed at the zero mark. Image - DIY lathe repair

After completing the alignment, they are determined with the base surface. It will serve as a reference for tracking the parallelism of the restored guides. When it comes to a lathe, those guides that go under the headstock (back) are most often chosen as the base ones. Practice shows that it is they who wear out the least during the operation of the equipment. It is advisable to pre-trim the selected as the main guides. This will remove minor wear and tear.

After that, you can start scraping the bed, constantly checking the parallelism of the machined surfaces. In some cases, an indicator is used to check the curvature (spiral) of the restored element. But its use is currently recognized as unreliable, due to the deviation (up to 0.01 millimeter) of the base guides from the horizontal. Such a deviation will give a considerable calculation error, which will be the higher, the longer the holder of the verification indicator has.

Note the fact that the parallelism of the guides under the headstock in relation to the mounting planes of the travel roller and screw, as well as the feed box, is often violated. Deviations from parallelism become the greater, the greater the number of scheduled repairs the unit has undergone. Each time, the repairmen have to spend a lot of time assembling the equipment, since the process of fitting the designated roller, screw and feed box to the place is really laborious and complicated.

After completing the preparation of all surfaces, proceed to scraping the guides. In the process of performing the procedure, their spiral twist and parallelism are constantly monitored.

The scribing of specific surfaces is done in a specific sequence. It can be different for each machine, so we will provide a flow chart for performing this procedure for a conventional screw-cutting lathe (for example, for a 1E61PM machine). In this case, the order of scraping the machine guides is such that first, as you understand, the guides for the headstock (back) are processed, and then the following guides: Image - DIY lathe repair

Under the clamping strips and directly under the carriage. Deviations from parallelism along the length of more than 15 microns are not allowed.
Caliper (transverse). In straightness, the error is possible up to 10 microns, in parallelism - up to 15 microns (indicators are controlled by a verification bridge and a surface plate).
Carriages (counter guides). During work, make sure that the difference in parallelism between the screw axis and the guides does not exceed 35 microns, using a triangular ruler.
Carriages (longitudinal guides). If these elements of the unit are worn out badly enough, it is imperative to use antifriction compounds to restore them. At the described stage of work, it is important to achieve adequate alignment of the shaft (running) and its landing zone, the reliability of the engagement of the longitudinal movement rack with the rack gear, the perpendicularity of the spindle axis and the movement of the caliper in the transverse direction.

In the future, restoration is carried out using the anti-friction composition of the tailstock guides. The purpose of these procedures is to achieve:

parallelism of the bed guides and the quill axis (at a length of 20 cm, an error of up to 30 microns is possible);
the alignment of the hole of the quill and the spindle (in the horizontal plane, permissible deviations at a length of 30 cm are 10 microns, in the vertical plane - 30 microns).

In situations where the turning equipment is out of order, it is absolutely not necessary to purchase a new expensive unit. After a competent repair, lathes will again be able to efficiently and efficiently perform all technological operations for metal processing. Before understanding such a process as the repair of a lathe, you need to remember what turning is and how the equipment for its implementation is arranged.It is not always possible to buy new equipment. There is only one way out - repairWhen carrying out turning, the problem is solved to reduce the diameter of the workpiece, which makes a rotational movement, being fixed in the spindle of the machine. Removal of the excess metal layer (due to which the diameter of the workpiece decreases) is performed by a cutter equipped with a cutting edge.It can move in the longitudinal (feed) and transverse directions. By setting the parameters of these movements (rotation, longitudinal and transverse movement of the cutting tool), it is possible to regulate the thickness of the removed metal layer and the shape of the chips and influence the quality of the processing performed.

The lathe support is designed to hold and move the cutting tool

On the lower slide, the caliper also moves transversely, but along separate guides (transverse slide), located perpendicular to the axis of rotation of the part.

A rotary plate is attached to the cross slide, with a special nut, on which there are guides for the movement of the upper slide. You can set the movement of the upper slide with a swivel screw.

The rotation of the upper slide in the horizontal plane occurs simultaneously with the plate. Thus, the installation of the cutting tool occurs at a given angle to the rotating part.

The machine is equipped with a cutting head (tool holder), which is fixed on the upper slide with special bolts and a separate handle. The movement of the caliper occurs along the lead screw, which is located under the travel shaft. This feed is done manually.

In the process of work on the 16k20 machine, there is natural wear and tear, loosening, loosening of the caliper fasteners. This is a natural process and its consequences must be constantly monitored through regular adjustments and adjustments.

The main components of the lathe

The following adjustments are made on the support of the 16k20 machine:

During the transverse and longitudinal movement of the support of the 16k20 machine tool along the slide, wear of the screw and their working surface occurs due to constant friction.

The presence of such free space leads to uneven movement of the caliper, jamming, oscillation during lateral loads that arise. Excessive clearance is removed using wedges, with which the carriage is pressed against the guides.
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Backlash appears in the helical gear. You can get rid of it without disassembly. using the fixing screw, which is located on this caliper movement device.
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During long-term work on metal on the 16k20 machine, wear and clogging of the oil seals occur, which are located at the ends of the carriage protrusion. Visually, this is determined when dirty stripes appear during the longitudinal movement of the caliper.

Lathe front cover with oil seal

In order to eliminate this phenomenon without disassembling the unit, it is necessary to rinse the felt padding and soak it with machine oil. If the worn out oil seals are completely unusable, they should be replaced with new ones.
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This lathe device wears out over time under constant significant loads in metal work.

Significant wear is easily identified by the surface condition of the guide slide. Small depressions may appear on them, which will prevent the free movement of the caliper in a given direction.

With timely regular maintenance, such repairs may not be necessary, but in the event of a defect of this kind repair should be done, and in case of severe wear - replacement.

The 16K20 caliper quite often requires carriage repair, which consists in restoring the lower guides that interact with the bed guides. Particular attention is required to maintain a stable perpendicular position of the carriage.

When repairing the caliper, it is necessary to check on both planes using a building level.
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The turning device with which metal work is done can be very simple. You can assemble a homemade machine with your own hands almost from improvised means, which are taken from mechanisms that have fallen into disrepair.

Homemade lathe

You should start with a metal frame welded from a channel, which will be the bed. From the left edge, a fixed front headstock is fixed on it, and a support is installed on the right. A self-made machine, made by hand, provides for a ready-made spindle with a chuck or faceplate.

The spindle receives torque from the electric motor through a V-belt transmission.

When the machine is working for metal, it is impossible to hold the cutter with your own hands (in contrast to working with wood), therefore, you will need a support that will move longitudinally. A tool holder is installed on it with the possibility of alternating it transversely to the direction of movement of the support itself.

The movement of the slide and the tool holder is set by the specified amount by means of a screw with a flywheel, which has a ring with metric divisions. The handwheel is manually driven.

In order to assemble a turning device with your own hands, you will need:

hydraulic cylinder;

shaft from the shock absorber;

corner, channel, metal beam;

electric motor;

two pulleys;

Belting.

Homemade lathe on a channelA homemade lathe with your own hands is assembled in this way:

A frame structure is assembled from two channels and two metal beams. When working in the future with parts longer than 50 mm, materials with a thickness of at least 3 mm for the corner and 30 mm for the rods should be used.

The longitudinal shafts are fixed on two channels with guide rails with petals, each of which is bolted or welded.

For the manufacture of the headstock, a hydraulic cylinder is used, the wall thickness of which must be at least 6 mm. Two bearings 203 are pressed into it.

A shaft is routed through bearings with an inner diameter of 17 mm.

Hydraulic the cylinder is filled with lubricant.

A nut with a large diameter is installed under the pulley to prevent the bearings from being squeezed out.

The finished pulley is taken from a used washing machine.

The caliper is made of a plate with cylindrical guides welded to it.

The chuck can be made from a piece of pipe of a suitable diameter, with nuts welded on it and holes made for 4 bolts.

The electric motor of the same washing machine (power 180 W), connected to the headstock by a belt drive, can serve as a drive.

The necessary information on the repair of a 1k62 screw-cutting lathe is indicated in the repair manual. Here you can also find information on the options for modernizing the machine.There can be various kinds of malfunctions in the machines. Many of these arise from failure to follow care and maintenance instructions.In any case, before proceeding with the elimination of the malfunction, you need to familiarize yourself with the list of the main possible malfunctions. Image - DIY lathe repair

If the nature of the malfunction occurred is identical with the one described, you must use the proposed elimination methods.

If the nature of the malfunction does not coincide with those listed and its elimination is difficult, contact the factory.

The list of main faults is given in table 1, lubrication system faults in table 2.

The nature of the malfunction

Causes of occurrence

Elimination methods

Drop or lack of supply voltage

Check the presence and value of voltage in the network

It is impossible to switch the block of gears 9, 10 (Fig. 6) with the handle 5 (characteristic sound

The gear block does not move out of neutral

Switch on the electric motor and (freewheel) switch over

Arbitrary shutdown of the electric motor during operation

Thermal jet tripping due to motor overload

Reduce cutting speed and pi feed

Spindle torque is less than specified in the manual

Insufficient belt tension

Increase belt tension

Friction clutch loose

Braking is too slow

Weak brake band tension

Increase brake band tension

Caliper feed gain is less than specified in the manual

Insufficiently tightened reloading device spring

Repair and restoration of the TV-4 screw-cutting lathe.
Everything I had to do was done with the help of like-minded people on the forum https://my.housecope.com/wp-content/uploads/ext/1697/
Special thanks to Alexander, a forum member under the nickname Alexs40102 for his compassion and patience.

The composition "Medium Rock" belongs to the performer Audionautix. License: Creative Commons Attribution (https://creativecommons.org/licenses/by/4.0/).
Executor:

#LatheTV-4
#EvgeniyBudilov MACHINE CLEANER from the engine from the WASHER. Review of the restored TV-4 lathe. Drilling machine with your own hands. SUPER drilling machine from DRILL and scrap materials. Attachment for THREADED RIVETS for a screwdriver. UNREALLY COOL machine made from an OLD SCREWDRIVER. This is the Best DIY Device. Every turner must be able to do this! Brake disc groove. Thoughts on a band saw. How our grandfathers cut the threads.

If you assemble a homemade metal lathe with your own hands, you can get at your disposal functional equipment for metal processing at no extra cost. For objectivity, we will consider not only the assembly process, but also the current offers of the finished product market. The information below will help you make a correct comparative analysis, taking into account financial capabilities, professional skills and other personal characteristics.

High-quality homemade products are in no way inferior to the factory counterpart

Compact equipment does not take up much space in the home workshop

With the help of a table metal lathe, you can quickly and efficiently perform various working operations:

processing of ends, grooves with the required level of accuracy;
expansion of existing conical and cylindrical holes (countersinking);
accurate cutting of workpieces according to the length established by the plan;
creation of a relief surface by rolling;
cutting of standard and special threads (external / internal).

Complex and unique products can be created without mistakes using a metal lathe for the home

Study carefully the materials in this article. If it is difficult to implement the project with your own hands, knowledge will be useful for an objective assessment of the range of specialized stores. In separate sections there is information about the rules of operation that will help to extend the service life of technological equipment and provide a high level of safety.

Even a small lathe weighs a lot, creates vibrations during operation. A reliable base (1) is required, on which functional units and individual parts are fixed. If it is intended to create a floor version, use reliable supports of the required length. The final height of the work area should be user-friendly.

Other components are listed in the following list:

A gearbox is placed in the headstock (3). It is designed to adjust the speed of rotation of the spindle (4), change the magnitude of the torque.
On the reverse side, the workpiece is supported by a tailstock (6). Taps, drills, and other tools are also installed here, if necessary.
In the standard processing mode, the cutters are fixed in a special holder (5).
This assembly is mounted on a support (8). For smooth horizontal movement, a screw mechanism is used, located in the apron (7).
The feed box (2) drives the drive shaft.

the carriage (1) and the entire block as a whole (17) are driven by the travel shaft (2);
the movement mechanism is connected with a special handle (15);
these skids (3) provide freedom of movement of the upper part in the transverse direction (12);
it is fixed on the swivel unit (4) with longitudinal guides (5);
the cutters are installed in the holder (6);
screws (7/8) are used to secure this part / tools;
the handle (9) can safely move the cutters at a distance from the working area;
fastening element (10) of the upper part (11);
for its precise movement in the appropriate directions, use the handles (13, 14) with a screw drive;
the handwheel (16) is used to move the caliper manually.

In a detailed study of this part of a metal lathe, it is necessary to take into account the increased loads to which it is subjected in the process of performing technological operations. It is necessary to pay attention to the large number of moving components.

Sturdy parts are not the only thing needed to maintain precision. Constant adjustments will help eliminate backlash to compensate for wear. It is recommended to replace damaged seals with new products.

Hereinafter, we will consider projects that are easy to reproduce on their own with clarifying comments. The example in the picture is more suitable for woodworking equipment. To work with strong workpieces for a long time, you should make a support shoe from a steel plate.

In addition to the standard equipment, such interchangeable attachments come in handy.

With their help, the basic capabilities of the tailstock are expanded. In the author's recommendations, it is proposed to remove part of the standard holder of the cartridge (3). This will allow to increase the working stroke of the tool, to process larger workpieces.

For the manufacture of homemade products, simple design solutions are used.

A belt drive (1) is used here, which is notable for its low cost, low noise level. A double pulley (2) is installed for stepping the torque. To extend the life of the spindle (3), a pair of ball bearings must be used. If necessary, holes are made in the body for periodic filling of grease.

As a rule, a metal lathe is equipped with three-jaw chucks.

These clamps are automatically centered without additional adjustment. Self-production of such units will cause difficulties.Therefore, this functional element of the headstock of a lathe can be bought in a store.

Models with four jaws are used for processing square workpieces.

It is better to make the main part of the holder in a collapsible design.

This will allow you to make repairs without unnecessary difficulties. Screws are screwed into the threaded holes, which firmly fix the tool. The distance between the plates is determined taking into account the size of the cutters.

A handle is installed on top for quick rotation of the assembly. This device allows you to quickly change tools for complex sequential processing of workpieces.

Making a metal lathe with your own hands: step-by-step instructions with comments

First stage: selection of a metal lathe device, preparation of project documentation

The following drawings show the completed project. Such a relatively simple metal lathe for a garage (workshop) is not too difficult to make on your own. Belts and some other components are standard items. Other parts can be made by yourself or ordered from a specialized workshop.

Construction, main parts, dimensions

Headstock and tailstock components

Travel mechanism and support

Component parts of the carriage, assembly drawing

To select the required accuracy of movement of the caliper, the lead screw thread pitch is changed. It is cut into a die on a screw-cutting machine. To strengthen the structure, connections are made using welding. Headstock bodies are made from a channel (# 12/14).

The project presented above is designed for the use of a power unit with a capacity of 450-600 W with a maximum rotational speed of the working shaft - 2500-3500 rpm.

In order to save money, some project authors use old electric motors from out-of-order household appliances.

Such solutions are quite suitable if you choose a working engine of sufficient power.

The reasonable cost of products in this category allows you to easily find an acceptable option in the retail network. In this case, you can count on the official manufacturer's guarantees.

In order not to be mistaken, you can study examples of factory machine tools for metal, successful homemade products. Based on such a mini-study, it is easy to conclude about the following proportions: for processing parts with a diameter of 8-12 cm and a length of 60-80 cm, electric motors with a power of 600-800 W are used. Standard air-cooled asynchronous type models are suitable. It is not recommended to use collector modifications. They sharply increase the speed when the load on the shaft decreases, which will be unsafe. To prevent such situations, you will have to use a reducer, which will complicate the design.

Electrical diagram of a metal lathe

One advantage of the belt drive should be emphasized. It prevents direct mechanical impact on the shaft from the tool in the transverse direction. This extends the life of the journal bearings.

This algorithm explains the sequence of actions when working with the above drawings. The use of other design documentation implies the introduction of appropriate changes in the assembly process.

They start with the headstock. A spindle is installed in it. Further, the entire unit is connected to the running pipe using a bolt fastening. A thread is preliminarily cut on the fastening parts. When performing this operation, carefully control the alignment of the parts.

At the next stage, a power frame is assembled from the channels. When the frame is made, the headstock is installed on it. Here, too, the parallelism of the running tube and the long frame parts must be carefully monitored. Make the markup exactly. The holes are drilled sequentially with an additional reamer bore, checking each attachment point.One or two mistakes will not unduly compromise the strength of the channel, so it is better to make a new precise hole in a different place, if necessary.

For your information! Do not forget to install spring steel washers, which ensure the reliability of bolted connections in high vibration conditions.

Factory tailstock of a metal lathe

When assembling this unit, special attention should be paid to the accuracy of the placement of the central axes of the spindle (1) and quill (2). If a mistake is made, conical surfaces will be obtained instead of cylindrical when machining workpieces. Also check the parallelism of these elements to the running pipe. The support bar (3) prevents the tailstock from unfolding. Steel spacers can be used for height adjustment.

Caliper parts are installed sequentially in accordance with the assembly drawing diagram. Particularly high precision is not needed here, since numerous adjustments are provided. If intensive use is expected, make individual units detachable in order to replace wearing parts at no extra cost.

At the final stage, an electric motor is installed, connected to the mains according to the selected scheme. They check the functionality of a metal lathe with their own hands in practice. To improve the appearance and protect against corrosion, some parts are coated with primer and paint.

This photo of a metal lathe clearly demonstrates the high quality of homemade products.

Video (click to play).

For processing workpieces made of wood, plastic, and other soft materials, the power of a typical household power tool is enough. This example describes how to make a functional machine with your own hands in 15-20 minutes. With the help of the last photos, the table tells about the creation of an improved design: