By the way: I wrote the answer about that knife while I had a brief break in my work. It so happened that today I started dismantling one of the spare engines for my client' 1950 BMW R35. I was particularly interested in a gearbox that was attached to the engine, because it is equipped with a hand operated gear switch lever. It seems that the engine along with the gearbox was used to propel not the motorcycle, but some household machinery and then was abandoned for a long time as all their exterior steel parts became heavily rusted. I managed to separate the gearbox and engine and I disassembled the gearbox. Alas, not much of parts could be used in the project.
What connection with the topic? After all this nasty-rusty business, I am starting to think that the reward of KZ starts to look attractive! Couldn't be much worse:-)
Of course, I'm just joking, however here are photos of that BMW gearbox.
Yes I've been told it's a rope working spike I've just taken some more pics of interesting tools I own! Next up is this spring loaded gun type hacksaw! My guess is you start with a small hole or slit in a wall or piece of metal then saw your way down pushing it in and out on the spring??