People assume the important equipment in the studio is the welder or the gantry. It's a magnet on a length of builder's twine. Maybe 40 cm of twine, a speaker magnet from a dead radio, and I lower it into whatever cavity I've built and listen for the click. Steel frame, hidden nail, a screw I forgot. If it snags, I have found the thing that will hold the weight. If it goes quiet the whole way down, I go back and rethink.

I have a laser level. It lives under a pile of rags. The magnet is in my jacket pocket right now and has been for maybe six years.

There is something honest about it. It cannot lie to me and it does not need batteries and when the piece is finished nobody will ever know it was there. Most of the work is like that.

Also the twine has a knot about a third of the way along that means nothing. I have forgotten what it was for. I will not be removing it.