The pile-screw foundation is so popular that literally in every village you can find numerous designs based on it. Since the installation technology of such a framework does not cause particular difficulties, some craftsmen went further and began to make screw piles with their own hands.
This is quite realistic, especially if you want to build a lightweight building on your site, and for the construction of a massive residential building it is better to give preference to factory products. We will make a reservation right away that such a process will not require sophisticated equipment, and this also indicates ease of operation.
Screw pile design
In order for the support to turn out to be of high quality and durable, it is necessary to familiarize yourself with its design features. A pile with blades includes several elements:
- the trunk, which is a round pipe. The thickness of its walls is 4 cm;
- a cone-shaped tip fixed to the lower end of the support;
- the blades forming a spiral coil welded onto a cone;
- tip - a cap that is welded to the top of the pipe.
The tip is needed when it is planned to build the ground part of the structure from wooden materials. To give the tip greater strength, it is usually reinforced with stiffeners. Drill holes (24 mm in diameter) in each corner of the plug.
Beginning of work
The first thing we need to do is draw up a drawing of a future screw pile. This may be the simplest sketch, but it will give you the opportunity to mark all the necessary dimensions of the support rod, and it will be easier to calculate the right amount of materials with it. Here, each element of the workpiece will be marked.
The drawing must specify:
- What diameter will the pipe be.
- The required length of the bearing, taking into account the cone.
- The height or angle of the cone.
- The distance from the bottom of the blade to the very top of the cone tip.
If you need supports for a wooden structure, do not forget to provide a head (cap) and reinforcement in the form of stiffeners. Here, the work can stall due to the need to accurately indicate the length of the pile, and you can find out only after the analysis of the soil has been carried out. We are interested in the depth of dense soils. The best way is to order a soil analysis in a specialized bureau, but you will have to pay a lot for such a service.
But, since you are unlikely to build a residential building on makeshift piles, you can do without waste that is inappropriate for an easy construction. You can ask friends or neighbors who have been seriously building, if they do not know such information, suddenly they can clarify it. The technology provides the following: along its length, the support should exceed the depth of the bearing layer by 0.5 m, it will be so much it will rise above ground level.
Having determined the sizes, you can start to make a blade at home, for which you will need:
- high-quality sheet steel;
- plasmoresis;
- vise;
- templates with which to mark the inner and outer diameter of the workpiece;
- equipment on which the spiral spiral is stretched (you can limit yourself to crowbar).
Work stages
Since you need to make more than one pile, you will be busy with compasses for a very long time. In this case, it is better to make special templates that will speed up the process of marking the blades.. Here you will need to make two templates yourself. On one of them it is necessary to draw a small circle with a diameter equal to the diameter of the pipe along its outer side.
The second template will contain a large circle, and its diameter will be equal to the outer diameter of the screw. A central axis must be applied to each template, making it easier to fit onto a steel strip at the time of marking. Now that the templates are ready, you can proceed to the next step.
Cover the strip
In order to minimize material consumption, it is necessary to properly cut the steel strip. Please note that its length and width will be a multiple of the outer diameter of the blade (workpiece):
- the width of the large template should lie without allowances. For example, it has a diameter of 250 mm, which means that the width of the strip should be all the same 250 mm;
- the length of the strip should be equal to the diameter of the blade template multiplied by the number of blanks. Clearance allowances are not needed here.
To achieve the same size of all screw blades, a strip must be drawn, for which a horizontal axis is drawn along the length of the blade, and a vertical axis, the step of which must necessarily be equal to the diameter of the screw blade. The first vertical line will extend from the short side of the strip at a distance that will be equal to ½ of the diameter of the workpiece.
Now we need to mark the circles, and the template will help us in this. The process can be carried out in random order, that is, you can start the markup with small circles, and complete with large, or in the reverse order, there is no difference.
Creating a helical spiral
When all the markup is ready, it is time to start cutting blanks. First, an incision is made starting from the vertical axis and to the inner circle, and then along the inner axis. At the end, you need to cut the outer contour of the screw blade.
Here we need equipment - a vise and an adjustable arm. The formed rings are fixed one after the other with a vice so that the vertical section is turned upwards, and then the ends are gently bent with a lever in opposite directions. After the first end has been bent, it is necessary to release the workpiece from the vice, turn it over to the other side, and bend the second end in the same way.
We measure the distance - it should be between 130 to 140 mm between them, with a blade diameter of 200 mm. Make sure that the end of the helical blade entering the ground is less bent than the top.
Please note that in this process this is the most difficult and crucial task, because an incorrectly adjusted angle will not allow you to screw the screw support into the ground.
Cone work
In industrial conditions, the tips are produced by the casting method, but for obvious reasons, the home technology has been modified, and we will make a cone out of a pipe - this is how screw piles are made in a private way.
Now back to the manufacturing process of the template. In this case, it will be a triangle that needs to be cut from a thin metal sheet (can be replaced with cardboard). The height of our template will be equal to the diameter of the pipe, multiplied by two.
The size of the base is determined by simple calculations:
- first, we calculate the circumference of the barrel in the context, for which the outer diameter of the barrel must be multiplied by 3.14;
- divide the resulting figure into the sectors from which the screw cone will be made. If we take a pipe whose diameter is 76 mm, then four sectors are quite enough for us. So we quickly and accurately calculated the base length of our template triangle.
We form a cone
We mark 4 segments with the help of a previously made template and with a grinder we cut them out of the pipe. The triangles that remained on the pipe must be bent with a sledgehammer to the center of the cross section without extra effort. You need to fill until they are completely closed. Now welding equipment comes into operation. Docking seams are welded with a welding machine.
If necessary, the number of triangle segments can be increased. Make sure that the weld seam is neat, otherwise it may diverge and efforts will be in vain.
When the blade is mounted on a cone, in no case should there be gaps. If they do exist, you will have to adjust the angle of the spiral. Check the distance from the bottom corner of the spiral to the conical top - you should get 50 mm. When the elements are tightly closed together, the joint is boiled smooth even seam. In no case should you allow an intermittent seam, because when screwing into the ground, a huge load will affect the screw.
It is time to weld the head and stiffeners, created in the form of triangles with a right angle and a leg of 50 mm. It is the leg that is welded to the bottom of the head and pipe.
This is how simple technology and absolutely simple equipment allow you to make excellent bladed piles yourself, on which you can equip a small lightweight structure.