During the winter of 2009, I had the honour to be a guest at the Palace Armouries in Malta. I took this opportunity to measure a shoulder armour. I felt that my shoulder armours were sorta good in that they "worked", but they looked like imposters. I needed to see and hold a real one for me to understand what details I was missing.
Mr. Cassar, the curator, found me a couple of fairly standard general issue shoulder armours, made in Milan around the time of the Great Siege of Malta. These shoulders were probably worn during that siege...they show all the signs of being made quick and while under pressure in a very competent shop.
Above is a close up of the upper cannon. Noteworthy points would be the stepped join at the inside of the arm, the flush rivets, the raw inside edges and the rolled edges everywhere which made the relatively light gauge bearable. The gauge of this particular armour was very light...by my estimate, in the region of 18 gauge, and maybe a bit less where the sander has taken off the hammer marks.
There seems to be a large number of people who feel that the light armour like this must have had a lot of heat treating to allow it to withstand combat. This material has been assayed, and the results pretty much throw such suppositions into a cocked hat. This is not high carbon steel, this material is low carbon enough to be considered iron, and it does not rely on heat treating to make it stiff, but rather on rolled edges and stepped fluting to do that job. Makes sense, a dented armour can still provide protection, heck, it even absorbed energy in the process of deforming, and if it is fairly malleable metal, it can be hammered back into place.
I have heard fans of the "alloy steel" camp state that the steel must have been alloyed with silicon in its manufacture, which would leave it stiff. Sorry dudes, nice idea but thanks for playing. You can tell in an assay whether the material under discussion is heat treated, or has ever been heat treated by the percentage of marstenite and cementite in the crystals. Fact is, these, these have been made as soft as possible by annealing, they were rolled, dished, and shaped, then issued to the troops. They seem to have very few stress fractures, and bullet holes deform as if the metal was made from 55 gallon oil drums.
I especially wanted to look closely at the buckles. Obviously leather has never lasted, but if you look closely, the centre bars of the buckles are attached to the armour by steel straps. Fairly straightforward one inch centre bar buckles.
Noteworthy point...the person doing the strap work used scraps of steel, and cast buckles. He did not bother to round the edges off, or otherwise worry about aesthetics. That being said, look at the beautiful articulation in the lames!
The word "spaulder" AND the word "spaudler" are NOT in the Oxford English Dictionary. If somebody can tell me the derivation, and provenance of this word, I will use it. Until then, I shall continue to just call it "shoulder armour". No, a dungeons and dragons concordance is not good enough!