To do this, we just need: a small sheet of old unnecessary metal 2 mm, a worthless speaker, more precisely a magnet from it, diameter 85 mm, width 15 mm, 4 bolts 6 mm, length 40 mm, nuts to bolts.
So, let's start, check with a metal angle that the angle of the metal sheet is clearly 90 degrees. If there is no factory square, then we go the other way, put a magnet so that it adheres flush to two edges.
To the lower edge of the magnet we put the ruler exactly marked, and cut it off.
Then we clean to white metal.
On the finished triangle, we make one more.
Next, we clamp the workpieces into a vice and process it to perfection with a file, both workpieces should be the same size.
When the blanks are ready, we put a magnet between them and mark the places for the hole, drill two blanks together.
Next, insert the bolts on one bolt, there are three nuts, two in the middle and one on top for the clamp.
In the center we also drill a hole
and twist the bolt, adjusting the magnet flush on all three sides so that it does not move, but clamp without fanaticism, if you squeeze the magnet can crack.
Now cut off the extra bolts that stick out.
That's all the square is ready. Check it, take a square profile and put a square on it.
Take another profile and attach to adaptation and weld.
Everything is fine, the strength of the magnet on the square is enough to prevent it from welding when welding, since it also heats up.
