Metal movement in forming armour

There are many ways to achieve a desired result when working with steel. I think that most modern people are used to thinking of the material as a sheet and the ways we think about wood or cloth get stuck in our minds. The original shape or thickness governs the result. This is most obvious when people start and they curl metal into forms that (very roughly) fit around a body part, add some straps and call it armour. Maybe they flare an edge, or roll an edge. Maybe they add some shaped pieces from Rough from the Hammer, but the metal movement is pretty simple. Even when people move to more advanced metal work, many elements still seem to based on the same idea. Cut out a piece, dish or raise it some and you get armour. You can also add some darts and welds to speed the dishing or raising. That can work, and it can work perfectly reasonably. If you are planning to do "production" work, that is probably the best way to do things. But metal can also be thought of more like clay than cloth. You don't just bend and seam it, you really push it around to make it go where you want. It can also help to "think outside the box" - twist your mind sideways when thinking about things. Just because a part of the piece of armour sticks out from the rest doesn't mean that you need to flare it out. That might be the easiest and best thing to do, or it might be better to take the metal from another part of the piece to minimize thinning.

First example - Greaves

A greave is a nice illustration of the concept. The simple form is a curled piece of metal with edges that allow it to fit onto the shin. Then people flare the bottom a little and dish the sides some and it gets a little better. After that people start trying to copy real pieces, or the shape of the lower leg and things get interesting. The desired shape is, in no way, a flat piece of metal that is curled up. The shape you really want is a lot more complicated, and a lot more interesting. It flows with the body. It follows the form of the leg, but often attempting to improve on the basic shape - to idealize the form while still allowing the wearer to move comfortably while being protected.

I expect that there are a lot of ways that you could achieve the desired shape. I don't think any of them are inherently better or worse than the other, as long as the result is correct. All of these are really describing how to get the overall flowing shape. Each will involve a certain amount of dishing/sinking/squashing at strategic spots to get the rounded shapes at the calf and ankle bones. I omit that part of the process for convenience. To allow for discussion I have created a listing of different methods. In the real world elements can be combined and adapted as the armour sees fit. But describing them as distinct helps to understand the thought processes behind them. A quick listing of possible ways you could attack the main problem of getting something that tapers in the top half and flares in the bottom half include:

Make a pattern that (roughly) allows you to have the material mimic the top two thirds of the result and flare out the bottom until it works. The result is a very, very thin lower edge, or a very thick upper part.
Cut the pattern in two halves, allowing you to get a flare when you weld the parts together down the middle. This works, but it is annoying and you have to clean up the weld down the center.`
Assemble the piece from even more parts, I have seen and can see up to about 4 (top, bottom and left, right) working. Much more than that and you are just adding more welds without much gain. If you like welding and don't like moving metal, this can work. I don't. That's just a personal preference. When Aaron and I made a greave form from 3/8" plate, we definitely did it this way.
Curl the piece to form a half tube and raise the middle in to bring it into the proper place. This allows the ends to maintain their original thickness. This appears to be the most common way these days. It can work very well, esp. when done hot. Small heats help move metal where you want it to move and have the cold parts keep their shape.
Curl the piece to match the desired profile then raise the sides down to fit to the leg. This can be very fast, if done hot. Small heats help move metal where you want it to move and have the cold parts keep their shape.
And then there is the way described below......

This shows a little experiment I did to see how I might use drawing instead of raising to make a greave. This was done cold from mild steel as an experiment. From my experience, annealed 1050 works similarly at this stage of processing. I am pretty sure I started with a piece of nominal 16g. This is thicker than people use for greaves, but the whole process is based on thinning, so I wanted to be sure to have enough material. Hammering and grinding and it will get thinner. I used a power hammer to start the process, but that is just because I had one. I have done the same process by hand. It took longer and I didn't lay out the pattern for intentional thinning of the top and bottom because that would just have added work. With a power hammer, this doesn't add much time and it was fun.

Click an image to see a larger view of it.

Pattern

This is approximately what the pattern should have looked like. I started with the same shape, but the sides were straight instead of curved, it had an extra inch on the bottom, and the foot was not cut out. I would likely add a little to the outside bottom corners or trim every where else down the side. This will help with a shortage of material at the bottom back corners after the piece was shaped. The foot hole is also very generic - you could make a 16th c. or 15th c. greave by trimming differently. Normally most people will cut this out very early in the process. When working this way the material in the cut-out isn't really in the way, so it can be left for later. This allows you to see where the material is going and adjust a little to match your preferred final form very easily. I was aiming for a 15th c. greave. I have relatively little rise on the outside because I planned to draw the metal out vertially there to achieve the proper shape. One of the goals was to play with a pretty generic shape that would have been "material efficient" and easy to cut with straight shears. That, and the fact that I hadn't actually used this exact method before is why I started without cutting out the foot.
If I were actually carefully building a greave for myself, I would probably start with a slightly narrower pattern since the result wraps a little far around. But I am pretty skinny (6 feet tall, 175 pounds). Starting with the right shape eliminates all of the hammering on material that just gets trimmed. One nice thing about using this method and a power hammer is that the initial shaping time is just a few minutes. So having some extra material isn't really a problem. When you are raising a large form an extra inch or two around the edge really adds to the work.
If I actually did this very often, I think that it would be pretty easy to know how much to flare in the various places to get a pretty even thickness end result and minimize the hand forming necessary to get a "pretty" shape. You could also have a process where the apprentice moves most of the metal and the skilled craftsman finishes it off getting the final shape pretty quickly.

Tools

The intial shaping was done with a cross pien on a flat anvil face. In my case, I used a power hammer to do this, but I was careful not to hit very hard. The force required is well within the bounds of hand hammer work. I have done it on a pair of greaves in the past. When you are whacking a piece of 16g mild steel sheet with a 50 pound power hammer, you really do want to have a pretty light touch.

Almost all of the hand shaping was done with the flatter faces of the left 3 hammers. They provide different shapes of "almost flat" faces that allow me to hammer over the outside curve and into the inside curves. The "raising hammer" was used a little bit from the inside to push some narrow areas out over a flat faced anvil. I expect that I could have done all of the work with a version of the second hammer face with slightly rounder corners, but I like to move back and forth between hammers that approximate the desired final shape. I expect that they didn't do that - it is too time consuming.

Much of the rough shaping was formed on a pipe stake.

Most of the rest of the shaping was done on the front half of the rounded horn of my bick horn. This allows me to get the right curve inside the piece to allow for shaping.
I did also use a flat anvil face and hammered from the inside and a hatchet stake for forming the crease. I also used a couple of slightly domed stakes for the rounded areas of the calf, but not a lot. I had achieved a lot of the real volume necessary using the power hammer and "squashing" the areas to shape.

Stages of hammering

Initial cross pien work - from the flat

This is what the piece looked like after the initial hammer work using the power hammer. It really looks like a mess, doesn't it? The goal of this stage is not to make a nice shape, it is to get material where you need it to achieve the desired final shape. I drew out the top section to provide some of the shape and to intentionally thin the area that would otherwise have remained thicker. I hammered the areas of the calf muscle bulges to get the rounded shape I will want by the time I am done. The center is flared vertically on each side and the bottom is flared the normal way. This allows me to move the metal around and thin the metal relatively evenly while getting the sweep in the center line that makes a nice greave. When I did this by hand, I did the central sideways flares when the piece was flat, and then worked the rest as necessary. I did not hammer nearly as much of the surface with a cross pien.

Viewed from the side after the rough flaring. It looks pretty stupid at this stage, but when you curl a piece up it flattens out a lot, so having a lot of flare is a good thing. I really had no idea how much flare I needed, but I thought this might be close to the right amount. In hind sight a little more of the vertical flaring a little lower down would be a good thing. It would help get the "kick" out at the ankle. It would also mean that you need even more material in those corners because the piece will bend forward more.

Viewed from the inside after the rough flaring. This helps to see how the hammer was placed to thin in the desired directions.

Curled up to approximate shape

The rough shaped curled up. No real additional shaping has been done, but the piece comes closer to fitting the leg.

The same curled up shape from the side.

And now hammered into a nicer shape

After some hammer work to move material around to make it look more like a greave.
Assuming the time stamps on the pictures are right, including taking pictures, this is about an hour into the process.

The same stage shown from the side. If I had dished the center of the top differently, and moved the side flaring down a little bit I am well on my way to the back of a near-floor length 16th c. greave. And it wouldn't require either lots of raising or huge amounts of flaring at the bottom.

And after a reasonable amount of work turning it from "greave like" to more "greave shaped"

From the front

The same stage, from the side. This shows the general sweep in the front center line. Most of the initial flaring was done in order to get the material in the right place to have this sweep without having to flare the bottom excessively. The top is flared at the center to allow for the muscle at the base of the knee cap. Since this was just for fun, this is where this greave part ended. It lies in the shop rusting away. But it shows what can be done.

Conclusion

This is really just an illustration of a concept. We think of a piece of armour as "flared" at the bottom. Often this could also be described as "longer at the sides" - when you think about it that way, a whole new way of working opens up.

Other applications of the concept

Burgonet cheek plate

I recently made a cheek plate for a burgonet. The cheekplate is dished over the ear so that it will fit the bowl and then "flared" at the bottom to mimic the tail. I did the work by dishing the top, flaring along the front and back sides and then along the bottom a little bit. Since I hit the entire surface, the result was relatively even in thickness. This put the material in the right place to get a nice "flare" without thinning the metal along the bottom. It is just another application of the same idea. You can see the result here:

Gusset

The other example I have used to illustrate "sideways" thinking is making a gusset. Specifically one of the ones with a nice big roll at the center. Like these:

From what I have seen, the typical pattern many armourers use to make one of these is a crescent. The design parallels the edge of the breastplate and the expected roll. This can work. It is probably pretty reasonable for a gusset with a relatively narrow parallel roll. I tranferred the shape of the gusset on the lower breastplate to paper using slits to allow me to fit to the roll. This is the resulting pattern. The marker line indicates the base of the roll. The slots let me fit the paper around the rivets.

The problem can be attacked in a different way when you want to make a "big" roll.

The basic pattern for these can be approximately a long, thin rectangle. If you want a really cool roll that gets huge at the center, adding some material there can help avoid trimming. Final material thickness is interesting if you do things this way. Specific techniques matter a lot, but in general you can end up with a relatively thin area underneath the breastplate (where you don't need material, and it can just get in the way of interaction with the gorget and backplate), relatively thick on the "flat" surface that extends the width of the breastplate where it isn't covered, a lot of thickness to make a solid roll (allowing it to work as a stop rib and to decorate and grind) and enough thickness to close the roll without excessive thinning.

I ran a couple of experimental runs for The Forging in Texas Labor day weekend 2025. One was done hot, one cold (just to show what can be done if you are a glutton for punishment). The first one illustrated was patterned after A-61 - the pointed breastplate above. I took it this far cold. The next step is to fit it to a breastplate, then close up the roll.

The second was done hot, and I took it farther through the process - but I left part of the roll open to illustrate thickness. There is no way I would do this if I were planning to finish the piece. It is always best to move the roll in stages, evenly along the entire length. This gusset has a much wider area that would sit under the body of the breastplate. That's just a feature of the one I was copying. It also means that heat was more important.

I do this infrequently - about every 5 years. That means that I forget the lessons learned. In both of these cases I flared the "body" side farther than I needed to. You can see that the roll side needed very little flare. If I had flared the body less, and flared the roll more the result would have been more even in thickness and it would have allowed me to flare the base of the roll and leave the part that will be closed less flared - partially closing the roll before any hammering was necessary.

Hourglass gauntlets

A lot of people make these - their form makes them very practical for modern combat. I think that most people place a weld down the wrist line, at least when making them for production. The more "authentically minded" raise the form - pushing the wrist in. A long time ago Aaron and I made a sample by flaring the cuff and metacarpal. This was fun, but there were some issues. First, we did it small scale. This let us get away with things that just don't scale up. Second, the wrist ended up app. the initial thickness of the material and the thickness tapered down a lot toward the edge of the cuff and the knuckles.

Before another Forging, I played with bashing out the rough form of an hourglass gauntlet using heat and my power hammer. Starting from 1/8" I first drew out the wrist area lengthwise. This was really just to thin the material. So the "initial" blank was thin in the middle and thick bands on each side. Next I whacked away with the cross pien in the thick areas to draw them out sideways. The thing looked like a mess, but a few whacks and it curled up into a gauntlet shape. It's been a long time, but I think that it took about 20 minutes.

Splint arms

Here are some examples of really cheap early 16th c. arms. These were made and sold by the thousand and needed to be efficient in both time and materials.

I think it is pretty easy to see that most of the parts for a pair of early 16th c. "splint" arms are basically rectangles of different shapes with some corners cut off. I extended the idea somewhat and used rectangles for the elbows too. By drawing the "wing" portion out vertically I formed both the "pucker" and some additional height in the "wing" and at the same time thinned the material. This meant that I had enough thickness in the "cop" area to just sink it out fast without ending up with a center that was too thin.

Breastplate

When you approach larger pieces, initial thickness becomes really important. You are moving a lot more metal a lot farther. Most modern armourers will form the initial volume of a breastplate by "dishing" or "raising." The old fashioned, straightforward 1980's (and often starting armourer) methods for dishing a breastplate end up with a piece where the edges are approximately the same thickness as the initial piece of sheet metal and the center is a lot thinner. So you generally have to start with a pretty thick piece of metal to achieve a semi-reasonable center thickness. Since almost anyone who raises a breastplate has heat, raising allows you to achieve a relatively even thickness across the entire area of the piece. If you are skilled and careful, this can be approximately the same as the initial sheet metal thickness. Either of these processes can be sped up and/or made more consistent by adding a couple of darts and welds to achieve the majority (or all) of the volume.

Most (we can talk about the exceptions at length) 15th and 16th c. breastplates I have handled are thicker in the middle than they are on the sides and at the top corners. When people are trying to kill you with lances, arrows and all kinds of nasty implements, it makes sense to put material and weight where you need it most. Given that, here is a little experiment I did showing one way to achieve this result in a straightforward way:

Making a model breastplate.

Helmets and Buckets

Patrick Thaden and I got together (virtually) and recorded a discussion about 17th c. bucket making and how the techniques could apply. It takes this "metal movement" to a whole other level. You can see the video here:

Mass production of armor?.