Possible Evidence of Rolling of Sheet Copper Alloy?

[Matt Lukes]

It's a subject that's been debated for a long time- whether or not the Romans actually used rollers to finish their sheet metal to an even, smooth and consistent thickness, as opposed to just hammering it that is- but the lack of the discovery of any such machines has made the consideration of the theory purely academic.

Well recently I noticed something that might be considered reasonable evidence of rolling of sheet copper alloy. I was working with a large sheet of brass, which was definitely sized with rollers, and noticed that there were lots of very minor linear scratches on its surface. This made me think of one detail I'd seen on a number of my original lorica segmentata copper alloy fittings- linear, even scratches on the surface that appear too regular and even to be a result of any kind of abrasive treatment (polishing, for example). I've found clear marks of this kind on three separate artifacts- one being extremely clear.

I've attached a close-up shot of the fitting, and the modern brass- interesting similarity, eh? :wink:

[markusaurelius]

I have similar ones wih the same feature. It seems the most likely reason I would guess.

[Et tu brute]

It definatley seems to fit, I can't think of anything else that would result with that type of consistent markings.

[Celer]

Salve,

Both David Sims and Alan Williams at Reading University have worked on this hypothesis before. As far as I can remember, they looked at a site in Spain (or South France) where a series of descending stepped terraces were used to utilise water power to run a mill. They saw no reason why identical structures couldn't be used to roll iron and brass sheets. It would certainly save time, and in the case of iron also prevent the wastage of iron being manually hammered out into sheets. It might also be used to make laminated sheeting that has apparently been found on segmentata, with iron on one side and steel on the other.

This is my memory of a lecture several years ago. The notes are long gone unfortunately so sorry if my brain fails me.

Vale,

Celer.

[aitor iriarte]

Julian,

You're referring to the Late Roman water mills of Barbegal, near Arles (France) 8)

Aitor

[Celer]

AHA! :lol:

[Matt Lukes]

Indeed there are many potential methods of power from slave to water- the reason, other than the very compelling evidence in the metal (lack of slag, evenness, surface markings, etc.), I find the idea of rolling compelling is the fact that even a small machine would do the job well- the benchtop rolling mill that's been in use for centuries (for sure), is all that's really necessary, not some large industrial machine like those we have today. Given that the widest common plate used in any Roman armor is on the order of 10-12cm in width, the rollers need only have been that long, thus the machine could have been quite small. Set up a number of them, each one with its rollers slightly closer together and voila.