Two young men with aprons and tools

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Here’s a little carte de visite I just got. I’m not sure why, but I’ve always loved photos of that era showing people in a largely empty studio basically standing there, framed in full length. And this one is probably my first occupational photo of that type. But what is their occupation? The aprons resemble those worn by, say, blacksmiths, and I’m guessing the tool on the right is a file. But I’m stumped by the tool on the left. Any suggestions? (I’m sure it will seem obvious once I find out.) Also, there’s no information on the photo about who they are, or the name or location of the photographer. Still, I’m happy with it.