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+--- Thread: Corbridge A Breastplates - to cross or not cross diagonally? (/showthread.php?tid=9708)
Corbridge A Breastplates - to cross or not cross diagonally? - sulla felix - 06-19-2007
OK, mid way through making my seg I am vexed by this question. I have a submarilis with padded shoulders, which according to Mike Bishop (in his Lorica Segmentata Handbook Vol 1) will make the breastplates meet vertically as opposed to diagonally crossing. Apparently if the breastplates are crossing this indicates a poor fit, a lack of shoulder padding, or both. Looking at lots of pictures of reenactors segs both scenarios are well represented. Looking at the Corbridge hoard excavation report some of the breastplate fittings look like they are less than paralell to the edge of the breastplate perhaps indicating that the plates crossed diagonally rather than in a perfect straight line. Speaking with the metal master Matt Lukes he is firmly of the opinion that the plates should cross diagonally, even taking account of the padding to the shoulders, which attempts to counter the natural slope of the shoulders (I think).
Looking at the way the mid collar plate is shaped and the way the top back plate is shaped where it joins the collar plate it does look as though the breastplates should cross diagonally. To make the breastplates meet vertically it almost seems as though a "twist" in the mid collar plate is required.
Any thoughts anyone?
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Marcus Caecilius Avitus - 06-19-2007
I think it's all down to how diagonally? in other words what angle. I use a subarmalis heavily padded with sheepskin, which makes the pltes sit not far of vertical, but there is a slight 'V'ing going on.
Another point with shoulder padding is it pushes the seg higher on your body to the neck opening meets a thinner part of your neck. withou padding the mid inner shoulder plates would rest on the lowest and widest part of you neck, causing increased splaying :? if you follow.
If the plates are widely splayed at the top this will stress the buckle mounts, particulrly in the case of Corbridge A. As I understand it, the original finds didn't show signs of this. Of course the definitive answer would come from Mike Bishop.
Re: Corbridge A Breastplates - to cross or not cross diagonally? - sulla felix - 06-19-2007
Mark,
I attach a picture of a Corbridge C made by Matt Lukes (for Tarbicus - please accept my apologies for using your picture without permission!) to indicate the degree of crossing diagonally. Note that the USG plates are pretty level allowing for padded shoulders (would need some fairly radical padding to make the level), but the breastplates still cross diagonally. When cutting/forming the plates this makes perfect sense as you lay them out.
I guess the buckle mounts will only be stressed if you place them at perfect right angles with the side and bottom of the breastplates. If, however, you place them at a slight angle they will not be stressed?
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Marcus Caecilius Avitus - 06-19-2007
Barry,
I've gone back and looked at a few of the sources and the posted picture and I'm starting to waiver.
In favour of the significant diagonally overlapping plates; the piccy of Jim's armour reinforces the diagonal cross as if they were forced vertical the neck opening would close up and be useless. Also looking at the original drawings (attcahed) it is quite clear that the rear shoulder plate has diagonal hinge mounting yet all other plates (moving forward) have perpendicular mountings hence the front chest plates will cross diagonally (although this will be offset slightly as the rear shoulder plate does not sit vertically agaisnt your back.
In favour of a minor diagonal overlap of the plates; The lack of wear previously stated (typically I can't find the source of this). Also the fact that the plates on the Newstead Pattern armour are most definitely mounted vertically, lends weight to a continuation of design feature.
Having said this all this is hypothetical as what is important is to cut the plates accurately to a credible pattern and assemble them follwing the original. Plate position will derive from this.
Having made my own seg. A couploe of pointers; A cardboard mock up is a must. Tailor the Girdle plates individually and over your full underkit Tunics, Subarmalis etc. Finally make sur the pointed shoulder sections (if you make them with a point) faces in to the neck (in common with many other people I followed the Robinson Drawing and not the original find).
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Hibernicus - 06-19-2007
Midcollar plate with twist.. exaggerated to illustrate the point
The "twist" varies by wearer and the subarmalis he's wearing but it helps the seg to sit well on the shoulder.
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Marcus Caecilius Avitus - 06-19-2007
Sean is this the left or right? Is the twist to ensure the diagonal overlap or straighten it?
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Matt Lukes - 06-19-2007
It's mainly because of the disparity between the widths of the upper back plates and the breast plates that indicates that in most cases, with respect to real artifacts, the latter must cross in order to ever meet. There's also the matter of the vertical fasteners' positions which also is often so far to the outside edge of a breast plate to require it to lie well across the chest to meet its upper girth hoop counterpart. When you add that the angle necessary for a cross causes the curve of the mid-collar plates to adopt a good-fit shape (follows the natural shape of the trapezius muscle), it makes even more sense.
Some little, more anecdotal things I've noticed about various artifacts include that at least one Corbridge A breastplate's neckline forms a nice, smooth curve when crossed with a mate (a good armor neckline), and also that if the breastplates simply met hanging vertically, the neckline of many would be restrictive to tilting the head down. Also that the angled bottom edge of the upper shoulder guard, the orientation of which is dependent on the shape of the mid-collar plate, from cuirass 3 of the Corbridge Hoard is actually horizontal when hanging at the angle of my own shoulder (at the angle of the trapezius), thus seeming to explain the reason for the shape. Also crossed breastplates form a good approximation of the usual shape of the arm holes on rigid-type armor- slightly more open at the bottom to allow the arm to cross the chest more freely.
Re: Corbridge A Breastplates - to cross or not cross diagonally? - sulla felix - 06-19-2007
Mark,
Thanks for the pointers. I did make a carboard mock up which was useful, but only really for sizing. The cardboard does not behave in the same way as the steel plates so is not really useful for sorting out the collar problems!
Matt,
All of those observations are fairly convincing for me!
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Matt Lukes - 06-19-2007
I forgot to mention that I have answers to one of the proposed issues with crossed plates- specifically the idea that it would be too hard on the lateral buckles. The truth is, and the photo of Jim's armor shows it quite nicely, that because the spike of the buckle is a point connection, the belt can easily rotate around that, reducing the downward force on the parts. And of course the leather belt itself is flexible so bends as well. Also the hinge of the buckle seems to be a common point of damage- I have several forward (buckle) halves, presumably broken away from their base plates, and one complete unit that is partly broken at the top suggesting lateral force did the breaking. I've seen one other like this as well. If the plates were indeed vertical, there's less of an explanation as to why the buckles were broken this way, but the angled breastplate idea does this well.
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Hibernicus - 06-19-2007
The top pic is front to back
The bottom pic is front on the left, back on the right
The twist in the Mid-collar Plate helps the shoulder elements sit well on the shoulder, helps the breastplate ride "sqaurer" (if that's your desire) and aligns the bottom of the Breastplate with the bottom of the Bottom Back Collar Plate
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Marcus Caecilius Avitus - 06-19-2007
Aha! now I see.
lorica - brennivs - tony drake - 06-19-2007
Svlla my plates are diagonal even if only slightly, and I agree with all the points raised ,it all depends on how it will fit on you ,and that it preforms all the defensive qualitys it was designed for
![[Image: lorica003.jpg]](http://i162.photobucket.com/albums/t272/brennivs/lorica003.jpg)
Re: Corbridge A Breastplates - to cross or not cross diagonally? - sulla felix - 06-20-2007
Brennivs - nice picture. That looks like an interesting surface to the steel plates?
Re: Corbridge A Breastplates - to cross or not cross diagonally? - sulla felix - 06-20-2007
Quote:Is the twist to ensure the diagonal overlap or straighten it?
Mark,
I would say this is definitely to induce a straight vertical joint in the breast plates. This is exactly the kind of "twist" I would need to avoid breastplates crossing diagonally. However, I am just not convinced that the available evidence supports such a course of action.
Re: Corbridge A Breastplates - to cross or not cross diagonally? - Hibernicus - 06-20-2007
The TWIST..
Keep in mind that the pic is an exagerration... it better illustrates the point.. AND it's not necessary for all who wear a seg... different body types need different adjustments to the plates...