Plate armor thicknesses

[Dewey]

I apologize if this has already been discussed, but what are the approximate thicknesses for the various levels of plate armor from Low Tech? For example would Light Plate be equivalent to, say, 20 gauge steel, Medium Plate to 16 gauge, and Heavy Plate to 12 gauge? I realize that medieval steel was a lot worse than modern homogeneous steel, but I'd like a ballpark to figure out what DR values modern reproduction armor would have for a post-apocalyptic game I'm planning.

[AlexanderHowl]

This really depends on the sheer strength and hardness of the steel. Steels can vary by a factor of 10 in sheer strength and by a factor of two in hardness. This is one of the reasons why modern plate armor can be so much better than historical plate armor.

In general, historical plate armor is made from soft steel and cushioned by a layer of cloth padding for comfort and safety (which also prevents the sweat of the wearer from corroding the armor). Light plate would probably be 1/8" thick, medium plate 3/16" thick, and heavy plate 1/4" thick. This does not include the thickness of the cloth padding.

[Anthony]

Modern reenactment armor steel isn't better quality than historical armor, it's just much much cheaper.

[DouglasCole]

Originally Posted by Dewey

I apologize if this has already been discussed, but what are the approximate thicknesses for the various levels of plate armor from Low Tech? For example would Light Plate be equivalent to, say, 20 gauge steel, Medium Plate to 16 gauge, and Heavy Plate to 12 gauge? I realize that medieval steel was a lot worse than modern homogeneous steel, but I'd like a ballpark to figure out what DR values modern reproduction armor would have for a post-apocalyptic game I'm planning.

Modern homogenized steel used to calibrate bullet stuff (Rolled Homogeneous Armor) is ballparked at DR 70 per inch, which gives approximately DR 2.75 per mm.

[StevenH]

Here is some info from a Quora question asking the same thing:
https://www.quora.com/How-thick-was-...l-and-the-skin


And here, from MyArmoury.com: http://myarmoury.com/talk/viewtopic.php?t=9475


Thicknesses ranged from 1-3mm on helmets, 1.5-2mm on the thickest parts of the breastplates (the front, tapering a bit on the sides).


Armor was built to protect; plate armor was good enough that historically shield use started to disappear, both because it wasn't as necessary and because if you are fighting another plate armor wearer a sword isn't going to be the best weapon to use--a poleaxe is. Swords are sidearms, not the primary weapon. You don't cut through armor. You bypass it by going for slits/chinks, hence estocs, rondels, and half-swording. Or flipping the sword around and doing a murder stroke, if you don't have a mace or warhammer handy.

[Varyon]

Pyramid #3/52's armor design article may be of use here, as might the follow-up article from Pyramid #3/85. Cheap iron is DR 52/inch, good iron is DR 68/inch, good steel (and RHA) is DR 70/inch, ~TL4 hardened steel is DR 81/inch (but can't be made very thick until ~TL6), and TL 8 ultra-strength steel is DR 116/inch. That's all armor steel, of course. Mild steel isn't on the list; a quick bit of Googling indicates it has ~80% of the protective value of RHA; assuming this works out to 80% of the DR, that's DR 56/inch (assuming the same density; RHA is apparently a bit denser than mild steel, but I can't find a density value for it with a quick search), only a bit better than cheap iron, and probably a W (if using the articles for armor design) of 0.725. Armor used on film sets and the like I think is often made of aluminum alloy (to reduce weight), which is only around DR 35/inch for armor-grade alloys.

The above should give you some decent ballparks. For example, 16-gauge (1/16") plate armor would give DR 2.2 if made of aluminum alloy, DR 3.5 if made of mild steel, DR 4.4 if made of RHA, DR 5 if made of TL 6 hardened steel, or DR 7.25 if made of TL 8 ultra-strength steel.

[Dewey]

Thanks all for the excellent answers, this was a big help! Most of my experience with armor has been with the SCA, which I know doesn't necessarily give a perfect notion of how things actually were historically.

[DanHoward]

Originally Posted by StevenH

Thicknesses ranged from 1-3mm on helmets, 1.5-2mm on the thickest parts of the breastplates (the front, tapering a bit on the sides).

The lightest extant breastplates are 1-1.5mm thick on the front. The heaviest are 8-9mm on the front.

[Keampe]

8-9mm? Which extant example is this? Not even a breastplate with plastron is that thick - at least I haven't seen one. Could you be referring to some sort of jousting armor? Even then.....

As to SCA armour it tends to be thicker than it's medieval counterparts when made of steel. It's designed to keep you safe from weekly fight practices and weekly event fights, with the modern sensibility of not considering a broken finger or some such acceptable during practice. Actual medieval armour tends to be quite thin - the 1-1.5mm on the front with a plastron maybe doubling that. It would likely not be used in practice, just saved for battle or parade.

- Shane

[Say, it isn't that bad!]

Most probably, such an example would be around the 17th-century (1600s), when gunpowder and pike were the king of the battlefield, and a very heavy breastplate might protect you from a shot or three past fifty yards.