To accurately weld any pipe structure, you need to be able to trim them correctly. At least half of the success depends on this. To properly trim a pipe, you just need to learn how to make the correct markings.
Marking a flat end
To mark the end of the pipe, you need to step back approximately 10 mm from the edge and wrap it in paper. The edges of the sheet are aligned so that when they are applied, an even line is formed. Now if you circle it, you will get a marking for trimming the ideal end.
Trimming the rounded end for a T-joint
To trim the straight end of a pipe for a T-shaped connection with another pipe, you need to wrap the workpiece in paper and connect its edges with tape.
The result is a template of the outer diameter. It is removed and leveled into a plane. This will be a pattern for half the circumference of the pipe. Having attached it to the pipe along the seam, you need to put 2 marks 10 mm long, which will divide the circle exactly in half.
Next, you need to attach a sheet of paper to the edges of the marks so that the middle of it reaches the end of the pipe, and outline it.This is done on the reverse side as well. The pipe is then cut along the lines.
The cut end has a sharp inner corner. It needs to be brought to perfection by polishing and trying it on in place. Then a template is made from it. To do this, the end is wrapped in paper, it is connected with tape and cut along the edge. The result is a template that makes it easy to draw the cut of all other blanks.
Rounded corner 90°
To obtain a safe rounded corner of 90°, it is necessary to trim one end of the pipe at 45°. To do this, you need to step back from its edge by half the diameter and draw a transverse line along the circle. Next, 2 marks are placed to divide it in half. One must be on the seam, the second is opposite.
Now you need to attach the paper to the end of the mark from the long edge of the pipe and to the second line from the end. A line is drawn along the sheet. Then the same is done on the other side, and the pipe is cut according to the markings. The result is a 45° end.
Paper is wrapped around the cut edge of the pipe, secured with tape and cut along the sawn end. On the pipe from concavity you need to make a mark at a distance of its diameter. Then the template is removed, turned over, aligned with the line, and its second edge is trimmed in the same way.
Now, in order to use the template, you need to place a mark on the pipe for the center of the bend and from it on the sides of a point at a distance of half its diameter. Then the template is aligned with them and outlined with a marker.
After this, you need to move it first to the left, then to the right to outline the rounded end. The circles formed by markings are cut out with a grinder, the pipe is bent and welded.
