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When arranging a site or in preparation for the summer and garden season, there is a need for arcs from a profile pipe. They are needed when constructing a greenhouse, assembling a gazebo or a canopy. It is unprofitable to buy already bent arcs – the price is two times higher than for the same flat rolled product. The way out is to do it yourself, and in order to facilitate the process (it’s very difficult with your hands), you need to make a pipe bender for a profile pipe. You will need a channel or corners, rolling rollers and some more details. Of the tools – a grinder with a disk for metal, a welding machine, a ruler.
Curved construction
The machine for bending a profile pipe is structurally different from the usual one. This is due, firstly, to the greater resistance of the profile to bending loads, and secondly, to the fact that the bending radius is usually required to be large. Therefore, there are three rollers in the design. Two of them are installed permanently, one remains mobile. With the help of a movable roller, the radius of curvature changes. In general, there are two types of pipe bender for a profile pipe: with a middle movable roller and with an extreme one (right or left – optional).
Pipe bender with middle movable roller
Two extreme rollers are fixed on the body. They are raised above the base plane. For the middle roller, a special U-shaped frame is brewed. In the middle of its jumper, a long clamping screw of large diameter is installed. A third roller is attached to the lower end of this screw (can be welded). By rotating this screw, the roller lowers and rises, changing the bending radius of the profile pipe.
A cloud is welded to one of the fixed rollers, with the help of which the pipe is rolled through the machine. In order to be able to apply less effort for rolling, two fixed rollers are connected by a chain. For efficient transmission of torque, sprockets are welded to the rollers (possible from a bicycle), a chain is selected for them. Such a simple mechanism makes bending a profile pipe much easier.
With extreme movable roller
In this design, the right or left roller is made movable. It moves along with part of the base. This part is connected to the rest of the frame with powerful metal loops.
You can change the height using a jack, as shown in the drawing. The height of the platform in this case is selected depending on the height of the jack. The bending radius is changed by lifting the movable part of the table.
Unlike the previous design, this pipe bender for a profile pipe is driven from the central roller – a handle is welded to it. To reduce the force required, it is also possible to weld the sprocket to two fixed rollers and transmit the torque using a chain.
What materials and design nuances are needed
The base of the pipe bender is made from a channel or two welded corners. The thickness of the shelves is at least 3 mm, select the width of the shelves and the back of the channel according to the available parts. One rule – the base must be massive and reliable.
Several holes can be made along the edges of the platform. Through them, you can fix the machine to some kind of heavy base using large-diameter self-tapping screws. Fixation is necessary, since when bending pipes with a thick wall, considerable effort has to be applied and it is more convenient to work if the machine is firmly fixed.
A few words about rollers. They should be made of good quality, preferably hardened steel. It is on the rollers and on the axles that hold them that most of the load falls.
It is necessary to say about the form of rollers. They should not be smooth – there should be rollers along the edges that will not allow the pipe to “walk” during rolling. Only under such conditions will the arc from the profile pipe be even, and not twisted. Ideally, each pipe size needs its own rollers. But then the design becomes more complicated – they need to be made removable, to think over a reliable method of fastening. The second option is to make videos of complex shape, such as in the photo. Carve several steps for different sizes of pipes.
The same photo shows that the upper part of the bed is uneven, but notched. With the help of such teeth, it is possible to rearrange the rollers at different distances and thus also adjust the bending radius.
In general, they assemble home-made bending machines for shaped pipes from what is at hand or what they find / buy inexpensive. Who has the opportunity – grinds rollers, inserts bearings. Those who do not have such an opportunity use what they have – up to the bushings from bicycle wheels. In general, it is necessary to understand the design and
Tricks to make pipe bending easier
Bearings are used to make the rollers move better. But, in principle, for a homemade pipe bender, which will be used only occasionally, you can simply make holders from a corner or channel. Make a hole in them, which is slightly larger than the axis on which the roller will be mounted. Pass this axle with a roller put on through the holes of the holders and somehow fix them (at least weld a couple of points that will be stoppers). During operation, for a better move, lubricate the friction points with a thick grease such as Litol. This is not suitable for industrial and semi-industrial production, but for making arcs for a greenhouse or a gazebo with your own hands – just right.
There is another trick that helps to reduce the required force when bending a profile pipe. You can use the principle of increasing transmission as in a bicycle. By the way, you can use sprockets from a bicycle. In this case, the handle that drives the rollers is welded to a small asterisk. It is installed somewhere on the body. Larger sprockets are welded on the shaft axis (but the teeth with the same pitch). All this is connected by a suitable chain.
And one more improvement – with the constant use of a pipe bender for a profile pipe, it makes sense to mechanize it. In this case, they put a motor that runs at low speeds.
The procedure for bending a profile pipe on homemade machines
You are unlikely to be able to get the required bending radius at a time – too much effort is required for this. It is impossible to create it manually. Get the required bend in several passes:
- First, the rollers are set so as to obtain a slight bend, the pipe is rolled in one direction, then it is removed from the rolls, unfolded and inserted with the other side. It is necessary to unfold to get an evenly curved pipe.
- With the same position of the rollers, it is pulled several times until the curvature is no longer added.
- If the required bending radius is not reached, change the position of the roller and repeat the steps again.
The change in the bending radius is obtained gradually, otherwise you cannot make an arc from a profile pipe on a home-made pipe bender. What if you need to repeat the same bend? Make a graduation – note to what height the roller moved, how many times it was rolled in each position. When repeated, the differences, if any, are insignificant.
The complexity of bending lies in the fact that there is no scale and it is difficult to get the intended bending radius without experience. Sooner or later you will get it, but a lot of material can be spoiled.
Video materials
Explanations and photos are good, but seeing the assembly process or the work of the finished unit is much more useful. The first video shows the process of assembling (welding) a manual pipe bender for a profile pipe. The variant with a movable middle roller is chosen. The second video is about the operation of a simple pipe bender with a movable platform. This option is not suitable for large sections, but it is able to bend a pipe of a small section up to 40 * 40 mm.
How to bend a profile pipe without a machine
There are two ways to get an arc from a profile pipe without a profile bender – using welding and a template. Let’s start with welding.
Get an arc by welding
The profile pipe is cut with a grinder on one side. They are made after 15-30 cm, depending on the required radius, section and wall thickness. The cuts should not touch one side – the one that will be outside.
The spare part prepared in this way is bent, giving the desired bend. For reliability, the edges of the arc can be fixed by welding a rod to them. Then they pass through all the cuts by welding, welding them. And the last stage is the grinding of the welding spots and the treatment with anti-corrosion compounds.
With the help of the template
Thin-walled profiled pipes can be bent by hand using templates. If you need some special shape, it can be cut from a piece of thick plywood or chipboard, fixed to the table with clamps. On the workbench, where we will bend the pipes, we make 8-10 holes. The template is placed near these holes.
At one end of the pipe, the holes are repeated; with their help, the pipe is attached to the workbench. Now the free end of the pipe begins to be pulled smoothly, forming a bend that repeats the shape. You need to pull smoothly, without jerking.
The template can also be made on the ground. Pipe-pegs are driven into the ground (at least half a meter deep). They form the required arc. For emphasis, two additional stakes are hammered, which are located away from the arc. The distance that you need to step back to the side is slightly more than the width of the pipe.
Having inserted the pipe, it is pulled towards the arc. Great effort is needed, hard work. It can only be obtained with a thin-walled seamless pipe. The seam has too much resistance in the seam area. It is very difficult to overcome it manually.