Rolling sheet metal and making rolls with your own hands. Homemade sheet bending machines (bending machines) Rolls drawing

The rolling machine consists of a massive base, feed and take-up shafts, a gearbox connecting them and a clamping device. The kinematic scheme of one of the design options is proposed in the figures.

Circuit specification:
1. Hand drive handle;
2. Pickup shaft;
3. Drive shaft;
4. Gear of the receiving shaft;
5. Drive shaft gear;
6. Foundation;
7. Side stand;
8. Shock absorber;
9. Tension plate;
10.Adjusting screws.

Gear design

The main structural elements are shafts.

Detailing.
Shaft and side stand.

Shafts must be made of steel and hardened. They should be turned on a lathe.
The length of the necks should be equal to the height of the ball bearings you have chosen, and one should be increased by the shank (the height of the handle mounting flange). The shank must have a diameter that allows the ball bearing to freely "pass" to the neck.
The situation is more complicated with the gearbox.

Detailing.
Gear.

If it is not possible to make gears (and this is possible only in the factory using special equipment) or to pick up a ready-made planetary gearbox to drive the shafts, then a chain drive from a bicycle is used. In this case, toothed gears - “asterisks” of the rear wheels of an adult road (the cheapest design, without bells and whistles and calipers) bicycle are installed on the axles of the shafts. In this case, it is necessary to perform milling work on the shaft neck to install the key.

We remind you that the shafts must rotate at exactly the same speed, since otherwise slippage of the processed material is possible (with all the ensuing unfortunate consequences). Therefore, new gears or ones that have not been in operation (without wear) should be installed. A spring-loaded chain tensioner with an "asterisk" from a small (children's) bicycle should be provided.

Pay attention to the compatibility of "asterisks" with a bicycle chain (a different module of gears is possible). To check compatibility, each gear should be “rolled” along the chain laid out on the table. When compatible, the teeth should easily fall into the links.

The chain is also better to use a new one. Along with the purchase of “stars” and a bicycle chain, you should buy a repair kit for it, which contains insert links and axle bushings. The chain, before installation, must be adjusted in size (in length) for our device. Here you will need the parts from this kit (how the replacement is indicated in the “Instructions for Use” of the repair kit).

Sheet metal rolling machine assembly technology

Assembly begins with pressing ball bearings (4 pieces) into sliders (4 pieces).

It is advisable to perform this operation in a bench vise.

Further, the shaft necks are pressed into the inner race of the ball bearings (inserted into the sliders). This is done on an anvil by the method of axial blows with a hammer through pads made of soft copper (another soft metal is possible: aluminum, etc.). Anyone who does not find the right ball bearings can press bronze bushings into the sliders, machined to fit his installation dimensions (taking into account the sliding fit for the shaft neck).

Two words about the foundation. As a base, depending on your needs and capabilities, any massive structure can be used: from a steel plate to a welded frame from a corner (or other profile).

The marking and installation of the side racks will be carried out "in place".

Assemble sliders (assembly with shafts) with side posts (4 pieces) and place on the base. When assembling sliders with racks, it is recommended to lubricate the guides of the latter with thick grease (for details on lubrication, see the end of the article). Check the free rotation of the shafts, and make markings for the installation of all side racks (rack sketch - see above). It is advisable to fasten the racks with the help of M 6 ... 8 bolts with a countersunk head (welding is not recommended - the entire structure will “lead”).
The sequence of mounting the side racks:

install two racks on one side (any), check the free play of the sliders of this side and check the markings for attaching the racks of the other side. If necessary, adjust the markup;
install one rack of the other side (similar to above), check the free play of the sliders (all!) and the rotation of the shafts. Check the layout of the installation of the last rack and, if necessary, adjust;
install the last rack (similar to above). Check the free play of the sliders and the rotation of the shafts.

The resulting jamming is eliminated by alternately loosening the fastening of the side racks and placing wedges under them from scraps of thin tin or other suitable pieces of metal.

A shock absorber (made of hard rubber) is placed on top of the sliders and a clamping bar is placed on it. With four screws, this bar presses the shock absorber to the sliders of the receiving shaft and the last one to the drive shaft. During operation, these screws regulate the pressure of one shaft on the other.

A manual drive handle is installed on the shank of the neck of the drive shaft - you can use the handle from a manual meat grinder.

In this case, on the shank under its connecting size, “remove the flat” with emery.
You have assembled homemade sheet metal rollers, but it is too early to start using them.

Final operations

After assembly, be sure to remove the burrs (with a file or any other tool at hand) and “fill up” (blunt) the sharp edges. To make the tool pleasant to use, it should be painted. This way, in addition to aesthetic properties, you will increase its anti-corrosion protection. Paint can be used pentaphthalic type "PF". Before painting, do not forget to clean (including degrease) metal surfaces.
And the final operation is lubrication. Check for grease on the slider guides (you greased them during assembly). Lubricate adjusting screws and bearings.
You can use any grease (grease, lithol, grease, etc.).

What can be improved in this design

The design offered to your attention has an independent adjustment of forces on the side racks. From above, if desired, you can install a gearbox that will equalize these efforts, and your device will look something like this.

note

Please note that the dimensions on our drawings and sketches are indicative and cannot be taken as executive. The proposed design documentation is a hint for DIY enthusiasts. It is intended only to show you the "direction of movement." Therefore, some (non-responsible) nodes have not been fully developed structurally and are “farmed away” to you, those who like to experiment. Moving in this direction, you will be able, based on your needs and capabilities, to develop an acceptable for you executive design documentation (a set of sketches) with executive dimensions and think over your device manufacturing technology.

We wish you success!

Where could I buy

If you still decide not to do it, but to buy a finished machine, select the contacts of the sellers on the page "".

The so-called rolls, used for working with metal blanks, are a special class machine, through which you can obtain bent profiles of any degree of complexity.

The main functional unit of such a mechanism is rolls made in the form of rotating cylinders, in the interval between which the initial tubular billet is formed. For different models of rollers, the number of such cylinders may be different (usually they are installed from 3 to 5 pieces).

Types of roller mechanisms

Several models of mechanisms of this class are known, differing both in the type of drive and in their performance characteristics. These are the following devices:

manual rollers;
electric rollers;
roller mechanisms equipped with a hydraulic drive.

Do-it-yourself manual rollers for a profile pipe are convenient, practical to use and have a relatively small size. A good owner who decides to purchase this tool will most likely have no problems installing or maintaining it. Rolls usually consist of the following parts:

Massive base (bed).
Feed and take-up rollers connected to each other by means of a chain transmission.
Set of special clamps.

The manual fixture is equipped with a special pipe that serves as a guide for the bent workpiece. A person handling such a mechanism must have "remarkable" physical strength. This is why these machines are best suited for small tubular products produced in minimal quantities.

Electric analogues have a significantly higher productivity, since the actuator that pulls the pipe through the rollers is driven by an electric motor. The efficiency of automatic broaching is noticeably increased, so that such equipment is used very often in industries focused on the production of large quantities of products.

As for the mechanisms with a hydraulic drive, they differ from all the devices presented above with increased power and can be classified as capital industrial equipment.

Homemade rollers

In the event that you decide to do independent repair work, you are unlikely to be able to do without the so-called "pipe bender". This statement applies mainly to those household operations that are directly related to the use of bent pipe profiles.

Self-assembly of rollers is possible in principle; and the main thing here is to follow certain instructions. In addition, the very procedure for installing mechanisms will require the performer to have certain skills in carrying out mechanical work and not all beginners will be able to do it.

Before starting the assembly procedures, you should prepare all the components, which can be used as various spare parts that are always available from almost every caring owner.

Assembly order

The order of the phased assembly of this household mechanism looks something like this:

First of all, the base (frame) is assembled, for the installation of which you can use a tubular frame or a channel of a suitable size.
The vertical support is made of a frame having a conventional U-shaped profile, in the upper open part of which a deforming element of the roller mechanism is installed. It should be noted that for its fastening you will need a special clamp equipped with a suitable thread. With this method of mounting the vertical support, its lower part is fixed directly under the frame; in this case, the deformation force is obtained due to the directed pressure on the feed rollers located at the edges.
To implement a do-it-yourself roller feed mechanism for profiled pipes, you will need a special transmission chain (an old chain from a bicycle can play its role). If you have the latter, you will need to pick up two sprockets from old bicycles and fix them on the supply and driven shafts. After installing the chain on the sprockets, it should be properly tensioned, and then (after checking for ease of movement) proceed to the installation of the feed handle.
As a material for the manufacture of the rollers themselves, we recommend that you use ordinary hardened steel.

The finished roll mechanism should be provided with the so-called radial adjustment, through which you can change the gap between the work rolls. In addition, it was not bad to provide for the possibility of angular (axial) adjustment.

Video

Secrets of work using the roller mechanism:

A lot of products are made from sheet metal - gutter systems, shaped parts for sheathing or metal tiles, ebbs for the basement, corners for profiled sheet structures, etc. All this can be done by a special bending machine - for sheet metal. How to make a sheet bender with your own hands and talk in this article.

Types of sheet benders

All these devices are classified as sheet bending machines. With your own hands, it is easiest to make an aggregate of the first group, a little more difficult - the third (rollers for sheet metal). Let's talk about them - from how to make a bending machine with your own hands.

Simple manual

Shaped metal parts cost a lot of money. Even more than corrugated board or metal tiles, therefore it makes sense to make the simplest sheet metal bending machine, and use it to make as many corners, ebbs and other similar parts as you need, and only to fit your size.

Bending machine - side projection

If you are worried about the appearance, then in vain. On sale today there is sheet metal not only galvanized, but also painted. In all designs, the sheet is fixed tightly, so that during operation it does not slip on the table, which means that the paint does not wear off or scratch. In places of bending, it is also not damaged. So the appearance of the products will be quite decent. If you try, they will look even better than what they sell on the market.

Powerful sheet bender from Taurus

This bending machine will require a flat surface (table), preferably metal, three corners with a shelf width of at least 45 mm, a metal thickness of at least 3 mm. If you plan to bend long blanks (more than a meter), it is advisable to take wider shelves and thicker metal. You can use tauri, but this is for bending sheets of metal of great thickness and length.

You will also need metal door hinges (two pieces), two large-diameter screws (10-20 mm), "lambs" on them, a spring. You will also need a welding machine - weld the hinges and make holes (or a drill with a drill for metal).

For a home-made sheet bender, a 70 mm tee was used - three pieces of 2.5 m each, two bolts 20 mm in diameter, a small piece of metal 5 mm thick (for cutting jibs), a spring. Here is the procedure:

Two brands are folded, cut out from both ends under the notch loops. The edges of the recesses are beveled at 45°. The third brand is cut in the same way, only the depth of the notch is made a little larger - this will be a clamping bar, so it should move freely.
Weld loops on both sides (boil from the face and from the inside).
To one of the taurus (farthest from you, if they are “opened”), two staves are welded on each side. They are needed so that you can install a clamping plate fixing bolt on them.
Weld the bolt nut to the jibs.
Install the clamping bar (the third cut-off brand), weld metal plates with a hole in the middle in the upper part. The hole diameter is slightly larger than the bolt diameter. Center the holes so that they are on the same vertical line with the welded nut. Weld.
Cut off the spring so that it raises the clamping bar by 5-7 mm. Pass the bolt into the "ear" of the clamping bar, put on the spring, tighten the nut. After installing the same spring on the other side, the clamping bar rises by itself when unscrewing.
Weld two pieces of reinforcement to the head of the screw - as handles for tightening.
Weld a handle to the movable (closest to you) brand. Everything can work.

This option is very powerful - you can bend long workpieces and a sheet of solid thickness. Such scales are not always in demand, but you can always reduce them. The video shows a similar design in a smaller size, but with a different clamp bar attachment. By the way, no one bothers to install a spring on the screw too - it will be easier to raise the bar. And this design is interesting in that it is possible to make flanging on it, which usually such devices cannot.

From a corner with a different type of clamping bar

This model is welded from a thick-walled angle, the bed is made like an ordinary construction goat, which is welded from the same angle. The handle is from a luggage trolley. An interesting design of the screws - they are long, the handle is curved in the form of the letter "G". Easy to unscrew/twist.

This homemade sheet metal bending machine has many features:

Now let's move on to the design of the clamping bar (pictured above). It is also made from a corner, but it is laid on the machine with a bend upwards. In order for the bar not to bend during operation, reinforcement is welded - metal jumpers. Small metal pads are welded on both ends of the bar, in which holes for the bolts are drilled.

Another important point is that the edge that faces the bend is cut off to get a sharper bend angle.

The clamping bar is placed on the machine, a spring is placed in the place where the nut is installed. The handle is put in place. If it does not press the bar, it is raised above the surface due to the elastic force of the spring. In this position, a workpiece is filled under it, exposed, pressed.

A spring is placed under the hole, then a bolt

Good choice for home use. It will not work to bend thick metal, but tin, galvanization - without difficulty.

Rolls for sheet metal or roll bender

This type of plate bender can have three types of drive:

manual;
hydraulic;
electric.

With their own hands they make rollers for sheet metal with a manual or electric drive. In manual ones they put 3 shafts, in electric ones they can be 3-4, but usually also three.

This machine needs a good solid foundation. It can be a separate bed or some kind of workbench or table. The basis of the design is rolls. They are made the same size. The two lower ones are installed permanently, the upper one is movable, so that in the lower position it is located between the rollers. By changing the distance between the lower rollers and the upper one, the radius of curvature changes.

The machine is set in motion with the help of a handle, which is attached to one of the shafts. Further, the torque is transmitted to other rollers through sprockets. They are selected so that the rotation speed is the same.

If it is supposed to produce pipes on the equipment, the upper roller is made removable on one side, with a quick fixation system. Having rolled the sheet into a pipe, there is no other way to pull it out.

Rollers are one of the most important devices in the metallurgical industry. They help to bend sheets of metal, pipes, as well as other oval and other parts. In addition, rollers are used in jewelry for accurate bending of products.

What are rollers, how three-roll models differ from four-roll ones, and how to make them with your own hands, we will describe below.

Rollers: principle of operation

The key working mechanism of the device is a rotating cylinder through which hot layers of metal are passed and bent. Rolling machines can be equipped with cylinders from 2 to 5 pieces, but three-roll and four-roll products are most often used.

The parts are bent by the action of the third rear roll, and the clamping radius depends on the distance between the top and rear roll.

Sometimes metal rollers break and need to be replaced. When working with iron, the machine must be constantly heated, and the layers of iron after the rollers go into the furnace, they are heated there, and then pumped again. After that, they go back to the machine.

After roller treatment the cross section of the metal decreases, and it becomes longer under the influence of the high temperature of the metal and the degree of pressure.

To obtain a cylindrical product, the rear shaft must be set parallel to the front, and to make a cone, the rear shaft is set at an angle relative to the front.

There are models of rollers with which you can process metal directly on the table, but they are not very functional. You can work with them simplify with fasteners. The cost of rollers depends on their dimensions. And if you decide to make a machine with your own hands, then you will save a lot.

The functions of modern rolling machines, home-made and factory, three-roll and four-roll, are as follows:

the ability to bend pipes up to 160 degrees;
work with metal pipes;
deformation of pipes, regardless of their diameter.

Machine Applications

Rolling machines are widely used in the production of such things as:

chimneys;
air ducts;
pipes;
ventilation systems;
drains.

Thanks to its compact size, rollers can be used anywhere, right at the construction site, and hand-held devices will not spoil the polymer coating of the metal.

For the food industry, crushing-type rollers are used, and for the chemical industry, sheet bending, sheeting and others.

Features of machine tools for metal

Without a rolling machine, it is impossible to give sheet metal a cylindrical shape, and pipe rollers help to equip the drainage system. Machines with forging cylinders are needed for cold bending of their metal blanks; also, thanks to the rollers, you can process:

plastic;
ductile metal;
rubber compounds.

You need to choose one or another machine depending on the thickness of the metal:

two-roll rollers include two parallel shafts, the upper one has a small section and is made of high-strength steel, and the lower one has a large section diameter and is made of rubber-coated steel. Depending on the pressure force of the pipe, its diameter at the outlet is selected;
three-roll can be symmetrical and asymmetric, they are often used in the manufacture of ventilation, round drains and radius parts. In addition, three-roll rollers are used in the processing of products made of copper, iron, steel, zinc, etc.;
four-roll structures equipped with an additional roll at the bottom to simplify the rolling process.

The most common rollers are three-roll and four-roll. So, three-roll have such distinctive properties:

a sheet whose width is less than 6 mm will slip between the rolls;
the rolling speed of the sheet should be a maximum of 5 m per minute;
it is difficult to control the machine due to the lack of exact coordinates of the metal clamping point;
affordable cost.

But four-roll rollers have the following characteristics:

Machine classification

According to the bending method, the rollers are:

segmental, where the pipes are bent under the action of one pulling segment;
mandrel, which deform thin-walled pipes;
spring. Due to the presence of a spring, the plastic bends without deformation;
crossbow, which are designed for pipes of one diameter or another.

Machine tools are divided into the following categories according to the method of use:

If you purchase or make a machine with your own hands for home small needs, then it is desirable that it has the following characteristics:

mobility and low weight;
compactness;
economical in terms of energy consumption, since a powerful device can damage home wiring.

Making a machine with your own hands

Naturally, assembling a machine with your own hands will be very costly in terms of time and workload, but if you plan to use it for minor repairs, then a home-made assembly will be a more economical option than a factory model, costing from 20 thousand rubles and more.

When assembling the rollers yourself, do not make the following mistakes:

do not allow cracks to appear on the metal profile;
do not allow compression and stretching of the surface at the point of load on the structural part;
do not compress or deform parts before work.

Before starting work, prepare the project drawing, materials and details. The work steps will be as follows:

Here is the finished product. As you can see, rollers can be purchased ready-made, or made by hand, having the required tools, drawings, and having the necessary skills.

The terms "rolling machine", "rolling machine" or "rollers" refers to the mechanism by which specialists make the necessary deformation of the necessary sheet metal blanks to perform a variety of repair work or for construction.

The main feature of this device is its high versatility and efficiency in operation. These qualities make it possible to use this machine in various types of production.

The main types of rollers and their purpose

Rolling machines in the modern world are very common in many enterprises for the production of metal products. Such a device can be easily made at home with your own hands. Using this mechanism, a specialist can make parts of various shapes from a metal sheet - cylindrical, oval or conical.

This task is performed with the help of shafts through which a sheet of metal passes. Rolling is a term denoting the name of the operation that solves these tasks. With the help of roller machines, the process of manufacturing pipes, arcuate devices, chimneys, drains and much more takes place.

Rolling devices, which are now produced on an industrial scale, are capable of processing sheets of various types of steel, as well as copper, aluminum, brass, and cast iron.

Manual machine for rolling sheet metal. The device of this type is manufactured in two versions: floor (when the flaring machine is installed on a rack), and desktop (when the unit is mounted on a workbench). To work on this type of rolling manual machine, you will have to make a lot of physical effort, although the undoubted advantage is ease of operation and a very simple design that allows you to save the reliability of the device for a long period of time.
Electromechanical rolling machine. A device of this type has a gearbox in its components. It allows you to significantly increase the efficiency of such a unit. An electromechanical machine is used in industrial production to process metal sheets and to slightly change the configuration of rolled tubes.
Roller machine with hydraulic drive. This type of machine is one of the most powerful and is often used at enterprises in various fields. Compared to manual and electromechanical machines, it has many times more working mechanisms in its design. These devices make the device more powerful. On this type of equipment, even the thickest metal sheets (up to 8 mm) can be bent without problems.

Advantages of manual rollers:

compactness of the device;
low weight;
good mobility;
electrical efficiency;
relatively low cost.

The design of the mechanism and the principle of operation

The main part of both factory-made and self-made rolling machines is considered to be a heavy frame that acts as a base. Usually it is made of cast iron or thick steel sheet. The body of the machine is attached to this powerful frame, which includes from two to nine rolls.

These rollers are also in some devices equipped with a special groove that allows you to bend not only metal sheets, but also be used for rolling pipes and rods.

Rollers are:

Metal polished.
Rubberized.

The technological capabilities of the roller mill are determined by its design features, in particular:

metal sheet width;
diameters of the rollers, on which the radius of the manufactured part directly depends;
the thickness of the metal itself;
the distance between the shafts (the maximum is measured);
production of cone-shaped elements.

In addition to the above, there are many more factors that affect the performance of rolling machines and ease of use.

Pipes on a roller machine are made quite simply:

First of all, the prepared metal sheet is clamped with a special handle between the shafts (middle and outer);
After that, with the help of the third roll, the workpiece is pressed against it;
Then the specialist starts the electric motor, or rotates the rolls with his own hands.

The whole process of work consists in the fact that the metal sheet, passing through the shafts at a designated speed, is bent under the necessary shafts.

To make pipes from the gutter with your own hands, it will be enough to purchase a roller machine for manual work. But the need for this kind of purchase will disappear if you make such a device with your own hands.

Varieties of rolling machines

Large-sized roller machines are often used in industrial production. Small workshops are quite content with handmade devices.

Roller machines are divided:

Mechanical. They are very easy to use and also low cost. This mechanism has three rollers that must be rotated manually. Gears transmit movement from the handle to the actuator. The mechanical rolling machine cannot bend the cone shape parts. They are most often used in small workshops and private workshops to make parts from very thin metal sheets.
Electromechanical. This type of rolling machine is more productive due to the additional presence of an electric drive that drives the actuator. The presence of this element allows you to process a metal sheet with a greater thickness and significantly reduce the time to complete the work. For a roller device with an electric motor, a brake is required.

Basic principles of roller operation

This structural element of the rolling machine is a very important and significant device in the production of metallurgical products. They are used for bending metal sheets, pipes and other parts of any shape.

The cylinder, which is in constant rotation, is the main working mechanism of the device. It is through this mechanism that heated metal sheets pass and bend. Working with iron, the machine needs constant heating.

The main functions of rolling devices:

Pipe bending 160 degrees.
Processing of metal pipes.
The possibility of deformation of pipes, regardless of their size and diameter.

The use of roller equipment in production

The rolling machine is indispensable in the production of such things:

chimney pipes;
air pipes;
pipes of various types and sizes;
ventilation systems;
water pipes.

Due to their small size, rollers are used in various industries, from the food industry to the chemical industry. Without a sheet metal machine, it is impossible to make an element of the desired shape (in this case, cylindrical). And rollers allow you to work with plastic, rubber compounds and various ductile metals. Making your choice in favor of the machine, you should pay attention to the thickness of the metal being processed.

A simple option for self-manufacturing rollers

Analyzing the simplicity of the design and operation of the roller machine, many people mistakenly believe that it is not difficult to assemble this device with their own hands. This is not entirely true. All this because most of the necessary components will need to be machined on their own. If the master has basic skills in turning, you can safely try to assemble a hand-drawn rolling machine at home.

For this purpose you will need:

Pins made of metal of different diameters.
Channel.
Bearings.
Bulgarian.
Welder.
Shafts.
Turning device.

The channel is needed in order to weld a frame out of it - a platform for the future rolling machine.
The frame for the roll device is made in the shape of the letter "P" and also from a channel. Further, reinforcing stops are welded to it, which are responsible for the pressure shaft stand.
After that, it is necessary to make three shafts, mount them on bearings and fix them on the corners, inserted into the base.
The location of the shaft will be changed using a threaded pin, secured from below with a washer.
The shaft that is on top should turn freely on bearings.

The parameters of the part to be processed will depend on the length of the machine shafts. The dimensions of the distance between the shafts, which is manually adjustable from below.

Do not allow cracks and scratches to appear on the metal profile;
Do not stretch and compress the platform at the point where there is the greatest stress on the structural component;
Do not deform the elements before starting work.

On this manual rolling device, in addition to metal sheets, pipes can also be bent.

Video: manual table rolling machine.

Famous brands of rolling devices

In the modern market, every master can find a suitable machine for himself at a normal cost. It is not difficult to find both a budget manual roll machine for bending metal sheets and pipes, and a full-fledged workshop or a large workshop.

Popular brands that produce handmade roller machines:

Stalex - this brand specializes in the production of very reliable and efficient devices. Their main purpose is the flaring of metal sheets, different in width and height.
Metalmaster is a manufacturing company that manufactures and sells reliable and highly functional rolling equipment. It is also easy and convenient to use when working with metal products. Most models of this brand are equipped with special grooves on the rolls. Therefore, on this roller machine, you can easily bend rods and pipes.
Encore-Corvette - this domestic brand, whose manufacturing country is China, produces a relatively cheap but reliable machine for expanding tubes and bending metal sheets, up to 1.5 mm thick.
Rolling machines with electromechanical drive:
VEM - this roller machine rarely requires expensive repairs due to its reliability. The device is additionally equipped with structural details, which makes it possible to significantly expand the specifics of this brand.

As the number of brands producing various types of rolling machines shows, the choice of goods in our time is huge. Without much effort, you can purchase both expensive equipment for manufacturing enterprises and small machines for manual work.