Articles
| Tavis | Damascus | Werre Guild
Armor is what S.C.A. combat revolves around. With the growing sophistication
of the work being done the field looks better and is on the average safer
every year. However, a great deal of armor is still being built and sold
that is neither safe nor S.C.A. legal. First of all there will always be
a certain amount of excessive force on the field. The amount of force that
can be delivered with legal weapons is a far cry above the force of a legal
blow. No matter how noble our intentions, mistakes will be made. Nothing
will keep this from occasionally occurring no matter how much we try to
minimize these cases. Secondly, there is a real tendency in the S.C.A. to
build armor with poor design and/or fit and inadequate space for padding.
This is just as dangerous as excessive force if not more so. In a poorly
built or fit piece of armor significant injury can occur at normal, legal
levels of force. As a result I feel certain pieces of armor (at the least
helms and gauntlets) should be designed to resist the greatest impact that
can be inflicted with the heaviest SCA weapons. It just isn't that much
more difficult to build safe armor than it is to build unsafe armor. By
the time the armorer has patterned, cut, formed, and connected the pieces
of a helmit doesn't take a significantly greater amount of time to make
sure the work is designed, fit and finished correctly. Also, armorers have
a certain responsibility to the fighters they armor.
While some amount of bruising to torso or limbs is inevitable and not usually
a problem, brain or spine injury is not acceptable. Because of this, the
helm is the single most important piece of armor. It is not difficult to
build a helm in which it is almost impossible to knock the wearer unconscious
and/or give them a concussion with even extremely excessive blows. If your
helm is uncomfortable or hurts when you are hit hard, it's not safe, period.
We continue to ignore the need to quantify the reality of what is happening
in heavy weapons combat. S.C.A. helms are required to have a maximum size
eyeslot and are subject to almost ridiculous scrutiny to prevent a tip from
sliding in while the fit of the skull and mass of the helm are never addressed!
What happens during combat is that fighters get hit in the head rather than
thrust in the face or killed by a blow to the body in by far the majority
of bouts. Most fighters have at least heard of someone being stunned or
knocked out during combat. This kind of incident, or even just getting rattled
for a moment after a hard hit will cause at least some cell damage. How
much is anybody's guess, but we could be establishing more precisely how
the helms we wear function when they are hit. I believe that we are ignoring
low level, cumulative brain injury due to excessive acceleration and impact.
In it's most basic function, the helm must prevent the skull, cervical vertebrae
and throat from actually being struck and therefore being cut or crushed,
or allowing the head to damage itself on the inner surface of the helm.
To do this it needs only to be able to sustain repeated blows from rattan
without caving in or contacting the skull. Fourteen gauge steel is generally
a safe minimum thickness for two reasons, after forming it requires less
maintenance than the legally required sixteen gauge steel, and in the case
of very heavy blows with S.C.A. legal greatswords is the thinnest mild steel
that will reliably not cave in. Additionally the helm needs to protect the
brain, spinal cord and spine from too rapid an acceleration. The helm itself
will always transfer force to the wearers head (and then brain). Controlling
the velocity at which it does so is the key. The brain (composed of water,
proteins and fat, with all the structural toughness of jello) floats in
a fluid cushion inside the skull with some attachment by connective tissue
and the spinal cord. Keeping it inside the skull is not enough, it must
be protected from too rapid an acceleration within, across or into the inner
surface of the skull. This may be accomplished two ways, by increasing mass
and padding effectively.
Mass- this is a critically important point about helm design. This
is where the Yugo vs. Cadillac rule applies: which one would you rather
drive during a head on collision? F=MA where Force equals Mass times Acceleration.
A twelve pound helm vs. a six pound helm requires a blow of twice the force
to accelerate at the same rate, into the head wearing it. Or put another
way , for blows of equal force, the heavier helm will undergo significantly
less acceleration. A six pound helm is far less safe than a ten pound helm.
Padding- the padding itself also performs three functions. First, it needs
to prevent the head impacting on the inside surface of the helm. Second,
it needs to absorb a blow's energy. Third, it must help the head move with
the helm rather than allowing the head to bounce around inside. Closed cell
foam will keep the skull away from the steel but unfortunately is stiff
enough to accelerate the skull at a high rate without absorbing much energy.
Open cell foam backed by a half inch layer of closed cell foam is better
at absorbing energy at the rates we require while still not allowing the
head to bottom out on the steel of the helm. I prefer either a dual layer
(open/closed cell) padding or some other means of mechanically absorbing
energy such as half sections of closed cell pipe insulation that will flex
and absorb energy at a lower rate than the foam will compress while still
being able to prevent bottoming out. Period padding systems such as strap
suspensions, felt, extremely thick cloth padding or a combination of these,
will still be inferior to modern foam.
The importance of good fit cannot be overemphasized. The heads size and
shape are the most critical part of how the helms proportions are determined.
If the respective shapes don't match correctly, the chances of the inner
surface of the helm contacting the head are greatly increased and the efficiency
of the padding is greatly reduced. Without exception , the cross section
of any one's head seen from above is a rounded "egg" shape- longer
front to back than it is wide across the ears. It is narrower still across
the temples, the human head is not round, not square, and not polyhedral
with flat sides. The cross section of the helm as seen from above should
reflect this. The back of the helm should not come close to the neck no
matter what position the head is in. There is no excuse for: large or poorly
made rivet heads inside the helm, large or globby welds inside, sharp metal
edges anywhere or bar ends mounted on the inside of the helm. The head is
measured with calipers and a cloth tape. The face, forehead, sides and back
of the head should be given room for between 1 to 1 1/4 inches of padding
and the top of the head 1 1/2 to 2 inches of padding. Padding is no substitute
for good fit or a smooth inner surface. Design is also important, if the
helm is long enough to rest on an unarmored breastbone or shoulders it can
be driven down causing injury. The nose, brow, chin and teeth should be
well inside the visor even under load. All parts (shell design and fit,
padding, mass, construction and materials, even the gorget), need to work
together for the most effective protection. Errors in any of these elements
of helm construction can allow injury. Spine protection is also critical.
Cervical vertebra damage is caused by; acceleration (fast rotation under
load can cause injury even well within the normal range of motion of the
neck/head), hyperextension (movement beyond normal range of motion can cause
connective tissue and disc damage, disc compression, spinal cord bruising
and tearing etc.), or compression of the spinal column (impact, crushing
etc. can break vertebra, crush spinal cord or surrounding tissues).
Another item that needs to be examined is the chin cup. In helms with a
fully barred face and a chin cup with no padding in front of the cheeks
the jaw hinge is the mechanism that absorbs most of the force from any blow
thrown directly at the face, in a light helm with chin cup a heavy blow
to the face is likely to be painful or injurious. Some specific things to
look for when purchasing a helm. Cost, Caveat Emptor, let the buyer beware!
Not to put too fine a point on it, if you have a 75$ head, buy a 75$ helm.
Maybe you could save up for a while eh? Weight, as above. Just ask. I wouldn't
wear anything under about 8 1/2 lb.
Fit These are the minimum series of measurements I recommend when
fitting a helm, one size does not fit all, neither do two sizes. During
a recent canton helm build, out of twelve helms we needed nine different
sizes to get optimum fit for everybody. 1.Largest circumference, usually
around the brow, tops of the ears, and occipital bulge at the back of the
skull. 2.Width at ears. 3.Width at temples. 4.Length front to back from
brow to occipital bulge. 5.Length diagonally from point of chin to rear
upper arc of skull above the occipital bulge. 6.Height from shoulders to
top of skull. 7.Height from under point of chin to top of skull. 8.Height
from eyes to top of skull. Using these measurements (and allowing space
for the nose and the above recommended padding) does make a difference,
and it is worth finding an armorer that understands this.
Rivet finish. If an armorer cannot make a decent rivet, how good
can their work possibly be? The correct way to "make" a rivet
head is: first, remove any burrs on either side of the rivet hole with an
oversize drill bit or a deburring tool; making certain that the rivet diameter
matches the holes into which it will be put for a good fit. See that it
projects at least a distance equal to it's diameter, but no more than one
and a half times it's diameter, through all the plates to be riveted. The
head of the rivet should then be seated, either in a securely-held rivet
set (as for dome heads), or against a suitably flat surface (as for tinner's
rivets), so that the hammer blows will not bend the rivet over sideways,
or drive the rivet out of the plates. Using a ball-pien hammer, starting
in the center, strike in a repeating spiral pattern around the top, gradually
forcing the metal into a low mushroom shape. When finished, the edge of
the rivet head should meet the surface of the plate tightly. When making
the rivethead, one should allow enough thickness to prevent the head from
tearing loose from the body of the rivet. This should be at least 2/3 of
the rivet shaft diameter. Rivet heads made on the inside of a helm must
be lower than a full dome and smooth in finish, preferably slightly flat
towards the center. Legal minimum iron rivet size of 1/8"dia. at 2.5"
spacing is ridiculously under strength and should not even be considered.
Also keep in mind that brass rivets are absolutely unsuited for structural
use in helms, and in any armor are not as strong as iron or steel and will
require closer attention during their lifespan to make sure they don't loosen
or shear off.
Plate thickness and edge finish. S.C.A. helms must use a minimum
of sixteen gauge steel, I won't use anything thinner than fourteen gauge,
and twelve gauge is just dandy, especially in styles with little overlap
and fewer rivets to increase weight. All plate edges should at least be
filed clean and slightly rounded. Lightly sanded (120 grit belt sanded)
is nicer. Lastly, if everything else checks out, appearance. A pretty, period
looking helm is nice but how much is it worth if it won't do the job?
I firmly believe that discussion of safe helm design should be moved to
the realm of modern scientific and medical knowledge rather than emotional
bias or opinion and I hope this article furthers that goal.
George Carroll, 940 Fairbanks, Kalamazoo MI 49001 Tavis MacIntosh, O.S.O.,
O.R.C., O.P.F. is a forcibly deported Scottish blacksmith living in Italy(better
climate anyway)
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