In an attempt to make a universal key, the author of the video came to a truly ingenious decision. The tool turned out to be simple and easy, but for its creation it was necessary to try, for example, to use argon welding and precisely adjust the sizes of all parts.
The donor of the craft was an ordinary large size open-end wrench. In the body of the future instrument, a smooth drink was made with the help of a grinder. A set of adjusting plates located on one axis is placed in the obtained recess.
The key principle is similar to using a set of adjustment probes, each plate reduces the distance between the jaws of the key, so you can choose the right size for the hexagon.