The German Helmet liner - Mod. 31
The "Innenausstattung 31" is the official German name of what we collectors more commonly call the "helmet liner" of the German steel helmet. The liner system model. 31 was patented by Schubert - Werke AG in 1928, and after having tested small lot of 2000 pieces for one and a half years the German Army and Navy adopted it for the helmets then in use (all dating from the WW1 period), and forwarded an initial order for a further 300,000 in 1931.
The liner consisted of two metal rings, an internal one to be used as a support for the leather lining (this last one attached to the ring by small aluminium split rivets), and an external one, intended to be directly secured to the helmet shell by means of three split rivets. The two rings were connected together with four pairs of very high quality steel springs with a total of eight "fingers" that still left some mobility to the parts (and allowed further comfort while wearing the helmet).
Below; firstly, leather lining split pins.
A selection of the various split rivets produced in different periods. The set made in brass are the earliest model, the others are wartime produced examples.
The new liners were produced to fit all helmets still in service at that time i.e. The mod. 16, mod. 18 and their variants. The later mod. 35, mod. 40 and mod. 42 helmets were all made in order to be compatible with this new liner system.
In theory what distinguished the liners to be applied on the first world war helmets from those reserved to the more recent models, are the initials placed on the right side of the external ring, near the size numbers. The initials "a/A" mean alter Art (old style), while "n/A" stands for neue Art (new style). In practice, liners bearing the initials a/A are very scarce.
As said, on the same side of the above mentioned initials there were the indications of the size. Two numbers were always present, the first being the shell size (60, 62, 64, 66, 68 or 70. This last size is very rare to find, it seems that such shells were produced only under special request) and the second describing the head size (from 53 up to 63).
The other side of the outer ring showed the producer markings.
The inner rings had only one marking in the front side indicating the head size. The head size was also repeated on the leather lining, on the first of the nine leather "fingers": sometimes the number, stamped either with dark blue or black ink, was inside a circle. In some cases maker markings can be encountered also on the back of the leather liner, but since that area was subjected to heavy usage, it's very possible that nowadays most of these markings have become illegible.
Below left to right: Variations in size markings as found on liners. Maker markings on different liners. Two liners in almost mint condition.
Below; A close-up of the leather linings. Note the different kinds of the size markings and the special drawstrings.
Below: another close-up that allows us to see the internal markings of a leather lining and the way the split pins secured the leather to the inner ring. Note also the inner felt band (sweatband) placed to make the liner more comfortable and the leather circular reinforcements placed over the drawstring holes.
EVOLUTION OF THE LINER SYSTEM
As said earlier, the liner was patented by the Schubert-Werke AG, that also
began to produce it directly. After the Reichsheer (and later the Wehrmacht)
forwarded orders of large quantities of product, the above mentioned
manufacturer, probably unable to cope with such a high demand alone, searched
other companies as subcontractors or partners (this has yet to be clarified). In
1937 at least 3 different manufacturers produced the liners.
The very first liners rings were produced in aluminium using plain metal bands. This first version proved to be very easy to break under heavy usage. That's why from late 1937 a new version was produced, still made in aluminium but with two rims on the upper and on the lower side, and with to additional aluminium plates riveted as reinforcements near the chinstrap rings attachments. Nonetheless the older liner system remained in use, sometimes they were even repaired when broken and used again.
Above; Detail of two ground dug early liners: they are both damaged on the same place, possibly the weaker one of the whole system. The second liner appears to have been field repaired with a metal tag secured by four rivets.
In both the aluminium based liners the chinstrap's rings were also made in aluminium and had square corners. Very high quality sheep leather was used for lining. The markings indicating the producer contained the full name of the manufacturer and sometimes even its full address. These markings could be either straight or circular, depending on the manufacturer.
As the war progressed many materials became harder to obtain. Some essential raw materials were replaced where possible by cheaper alternatives. This was the case for the helmet liners too. From 1940 the rings were made in zinc coated steel. Since steel is sturdier than aluminium, the lateral reinforcements plates were not necessary anymore. Only the side rims remained in use. The quality of the leather lining changed as well: even if sheep skin continued to be used, pig and goat skin were also introduced.
The chinstrap's rings were made in
steel, and had rounded corners. In order not to aid Allied Intelligence in
finding new targets for bombing raids, the producers markings were gradually
replaced from 1943 with numerical code numbers, the so called
Reichsbetriebsnummer or R.B.Nr.
The typical liner systems produced at the end of the war were made in zinc
coated steel, mounted a very low quality pig skin leather liner and had the
manufacturer marking encoded with the RBNr.
Above; The three different variations of helmet liners encountered. Note the chinstrap ring on the last model, with rounded angles instead of the square angles encountered in the previous two aluminium variations.
The table on the following page is the result of the examination of around 100 liner systems, and must not to be considered as a complete list of manufacturers, markings or year of production.
On the first column there is the list of the producers identified and the different markings variations encountered on the liners. The RBNr codes are mentioned apart, even if they were be very probably the identifications of the producers found "in clear" on earlier rings.
It is still very hard to find out which code applies to which maker.
The second column specifies if the particular marking found is straight or circular.
The third column indicates the type of ring on the liner in question: aluminium first type (Al1), aluminium second type (rimmed and reinforced, Al2), or the later version in steel.
The fourth and last column indicates the date of production of the examined liner.
Even if, this cannot to be considered as a final and complete work, we think the examination of this table warrants consideration.
- The earliest liners commonly
encountered date back to 1937; of the 100 liners examined for this study only
one earlier type was found (made in 1931), so an early dated liner must be
considered scarce.
- The same applies for later liners produced: the latest that we have examined
were made in 1944. We don't know if 1945 dated rings were ever produced, some
say that if they were made, they kept the "1944" markings. In any case, a 1945
marked liner ring, if such types exist, would have to be regarded as extremely
rare.
- The earliest aluminium second type rings found were made by the Metal-Lederverarbeitung
WZ in 1937 but first type rings were also found with the same year and producer
markings. So very probably 1937 is the year of introduction of the aluminium
second type ring variation, even though it appears Schubert Werk and the B&C
introduced the new model only from 1938.
- The steel liners began to be produced in 1940, but in that year the firm
Metal-Lederverarbeitung WZ still made the aluminium version.
- Some producers changed the markings on the liner, as the Schubert Werk and the
B&C. In particular, the B&C changed in 1942 the location of the manufacture,
from Berlin to Litmannstadt (today known as Lodz, Poland).
- The Metallwarenfabrik FWM's marking was found only with the date of production
1942. Probably this manufacture began to make liners late in the war, and from
1943 adopted the RBNr code.
BIBLIOGRAPHY Books - Baer L., The history of the german steel helmet 1916-1945 - Baer L., Vom Stahlhelm zum Gefechtshelm (in german) - Letonturier P., Le casque allemande (in french) - Radovic B., German helmets of the second world war
Website - http://www.german-helmets.com