In our back garden when I was a boy, we had an old signal box. I don't know where it came from - we certainly didn't have a (full size) railway to go with it. My grandfather (always known as GP) lived in the cottage next door and used the signal box as a workshop; I spent a good deal of time there, avoiding homework and learning how to make stuff. On my workbench is a steel try square which is in daily use just as it has been for some four generations: it was in the signal box when I was a bo