03-28-2007, 06:02 AM
Please excuse my poor abilities at explaining these ideas, but I'll do my best. This may take a while.
I think that there is an issue here for some people. I'm not sure why it is more pronounced for some than others.
From a conceptual standpoint, concentric rings of the same diameter (or circumference) are simply impossible. even if they are stagger stepped. It's a matter of geometry. Tapering is one solution that is popular. But it is not the only one. One un-appealing possibility is to tie the girdle plates further apart as you go up. This would probably leave a vulnerable open "V" near the top. Clearly not a good idea.
I simply force tied mine together using a special constrictor knot. This unfortunately caused the top girdle plates to angle down in the middle. causing a very wide but shallow "V" to form between the top front girdle plates and the breast plates. This was very annoying and extremely persistent. Nothing I tried could get them to follow a straight horizontal line. Not to mention that it should be impossible to get these plates of identical circumference to form concentric rings. So what was happening?
I have concluded, that under force the plates were twisting at the ends. The bottoms of the plates were twisting outward and the tops of the plates were twisting inward. This meant that the plates formed rings where the bottom of the ring had a greater circumference than the top. Therefore the top of the rings were able to nest in the bottom of the ring above them.
Could it be this simple? Not quite. You see the funny thing is that this twisting action causes the curved girdle plates to bend down. Try it. It only works with curved plates. The more you twist, the more it bends down. But if this is happening in both the front and the back, why can't you just lift them to the horizontal line? Because doing so would cause the sides of the plate to rotate, the tops of the sides would rotate outward and the bottoms would rotate inward. But this is the exact opposite of what is necessary to make the plates nest correctly due to the matching circumference problem.
Now of course these plates are tied at the bottom so the circumference at the bottom can't actually increase from this twisting. Therefore the upper circumference gets decreased even more. I experimented with mounting a plate horizontally in a vice. I exaggerated the amount of twist for demonstration. If you look at my pictures, you'll see that the vertical edge is off vertical. The top edge of the plate is actually the same length as they were cut that way, so it just ends up overlapping further.
Tapering is one method of resolving the problem. But may not have been the one (or at least not the only one) the Romans would have used. The Romans may have made other accommodations. Looking at the Corbridge report I found What I consider to be possible evidence of just such an issue and the accomodations made.
In figure 66, you can see that some of the plates are curved. I suggest that maybe this curvature is caused by the twisting causing the plates to bend downward at the ends.
In figure 57, you can see that the ends of the plates (particularly the top plate) are cut at an angle. This would correct the end plate angle caused by the twisting. Although as far as I can see this would be for cosmetic reasons only.
In figure 68, you can see that the top tie loops are mounted on an upward diagonal and the attachment hooks are also at an angle off the vertical. But when the plate is twisted and bends down on both ends these would become horizontal and vertical. Allowing attachments to be made along the horizontal and vertical lines which would be stronger and cause less stress to the attachment hardware.
Perhaps different craftsmen resolved these issues in different ways. Some may have tapered the plates. Some may have hammered out the bottoms of the plates so that they were actually a little wider at the bottom, and not have to twist. Though this would require more armoring skills. Some may have cut the ends at an angle or mounted the hardware at an angle. Some may have done nothing or something completely different. Some legionaries may have just been issued their armor and had to make do. And for some it may have been perfect.
I think that there is an issue here for some people. I'm not sure why it is more pronounced for some than others.
From a conceptual standpoint, concentric rings of the same diameter (or circumference) are simply impossible. even if they are stagger stepped. It's a matter of geometry. Tapering is one solution that is popular. But it is not the only one. One un-appealing possibility is to tie the girdle plates further apart as you go up. This would probably leave a vulnerable open "V" near the top. Clearly not a good idea.
I simply force tied mine together using a special constrictor knot. This unfortunately caused the top girdle plates to angle down in the middle. causing a very wide but shallow "V" to form between the top front girdle plates and the breast plates. This was very annoying and extremely persistent. Nothing I tried could get them to follow a straight horizontal line. Not to mention that it should be impossible to get these plates of identical circumference to form concentric rings. So what was happening?
I have concluded, that under force the plates were twisting at the ends. The bottoms of the plates were twisting outward and the tops of the plates were twisting inward. This meant that the plates formed rings where the bottom of the ring had a greater circumference than the top. Therefore the top of the rings were able to nest in the bottom of the ring above them.
Could it be this simple? Not quite. You see the funny thing is that this twisting action causes the curved girdle plates to bend down. Try it. It only works with curved plates. The more you twist, the more it bends down. But if this is happening in both the front and the back, why can't you just lift them to the horizontal line? Because doing so would cause the sides of the plate to rotate, the tops of the sides would rotate outward and the bottoms would rotate inward. But this is the exact opposite of what is necessary to make the plates nest correctly due to the matching circumference problem.
Now of course these plates are tied at the bottom so the circumference at the bottom can't actually increase from this twisting. Therefore the upper circumference gets decreased even more. I experimented with mounting a plate horizontally in a vice. I exaggerated the amount of twist for demonstration. If you look at my pictures, you'll see that the vertical edge is off vertical. The top edge of the plate is actually the same length as they were cut that way, so it just ends up overlapping further.
Tapering is one method of resolving the problem. But may not have been the one (or at least not the only one) the Romans would have used. The Romans may have made other accommodations. Looking at the Corbridge report I found What I consider to be possible evidence of just such an issue and the accomodations made.
In figure 66, you can see that some of the plates are curved. I suggest that maybe this curvature is caused by the twisting causing the plates to bend downward at the ends.
In figure 57, you can see that the ends of the plates (particularly the top plate) are cut at an angle. This would correct the end plate angle caused by the twisting. Although as far as I can see this would be for cosmetic reasons only.
In figure 68, you can see that the top tie loops are mounted on an upward diagonal and the attachment hooks are also at an angle off the vertical. But when the plate is twisted and bends down on both ends these would become horizontal and vertical. Allowing attachments to be made along the horizontal and vertical lines which would be stronger and cause less stress to the attachment hardware.
Perhaps different craftsmen resolved these issues in different ways. Some may have tapered the plates. Some may have hammered out the bottoms of the plates so that they were actually a little wider at the bottom, and not have to twist. Though this would require more armoring skills. Some may have cut the ends at an angle or mounted the hardware at an angle. Some may have done nothing or something completely different. Some legionaries may have just been issued their armor and had to make do. And for some it may have been perfect.
>|P. Dominus Antonius|<
Leg XX VV
Tony Dah m
Oderint dum metuant - Cicero
Si vis pacem, para bellum - Vegetius
Leg XX VV
Tony Dah m
Oderint dum metuant - Cicero
Si vis pacem, para bellum - Vegetius