I'm going from the photo also, It seems to be a solid one piece mallable casting, only moving part is the screw!? The screw looks like one thats the same as a carpenters adjustable bar clamp. My latest thought that it was used with ropes or slings?
Graeme
Rope or heavy cording were my first thought, actually. I've been thinking about what trade, what task would use such a clamp. Barrel making could use a tool like this, except the screw would put more pressure on one stave than all the rest, and that doesn't seem a good idea. It would work best as some kind of band clamp if there were something solid between the pieces clamped this way. Besides, coopers had their own developed tools, and I don't recognize this as a cooper's tool, not that I've seen anyway.
What occurred to me is that it would be useful to carpenters making up hollow pillars. Assembled from several planks, much like a barrel, this clamp would be useful in assembly, much like a band clamp, especially if the pillar tapered in a shallow arch.
