The process of manufacturing parts (pretzel) for the assembly of a forged fence.

You need a steel bar round or square, it does not matter, the length of the workpiece is about 1 meter here, so that it was more convenient to work with it, the bars were used with a diameter of 14 and 16 mm.
The end of the rod is pulled down like a screwdriver:

The video shows the approximate process of the delay, in general we make a square from it and alternately punch and pull the sides, then flatten and round the edges.

You can handle all the workpieces at once so that you do not return to this stage later.
If necessary, you can delay the ends on both sides:

After that, it will be necessary to twist the ball from the thin end of the rod and then bend it into a smoothly expanding spiral. It looks like this:

And so having made a ball at the end and twisted a little into a spiral, then with the help of such a simple device to screw the part to the desired length and size.