I am in the progress of building out a medieval woodworking tool box. I thought that one of the first tools a woodworker would need would be a ruler. I cut a piece of Aspen and began to mark out the "inches" on it. Before marking it I did some research to find out the standard measure. I found that most wood workers would use the width of their thumb as the unit standard. As long as the measure was consistently used it really didn't matter if I called it 10 thumbs and you called it 14. I took a set of calipers to measure the width of my thumb and darn it if my thumb isn't exactly one inch wide.
While it looks like my rule is marked with modern inches, it is in fact marked with increments the width of my own thumb.... which just so happen to be one inch wide.
I was happy with the progress so far, and then I failed. I tried using some of my old black walnut stain and it didn't take very well to the wood I was using. The rule became a dirty looking piece of wood which was now hard to read.
I will have to try and make another one at some point in the future because I don't like the look of this one. Way too dark for my liking. I have tried to use it on other projects and found the markings very tough to read. It will have to serve for demos, until I make another one.