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Mask Overview[]
The M. 1938 was developed to replace the by then obsolete M. 1931, which was large and cumbersome with its heavy weight. Attempts at reducing the M. 1931's size had already taken place by 1935, where the Forsøgs-Gasmaske, M. 1936 was developed. From there, it was determined that the M. 1931 platform was to be ditched. Hærens Laboratorium sought inspiration from its neighbours’ developments, and would be most inflluenced by Germany, who had by then recently adopted the Gm.30. Attempts to adapt the Gm.30 were made, but elements from the Gm.24 were ultimately implemented as well, resulting in the M. 1938.
Features:[]
- Cast aluminium valve-housing threaded in 42mm, which can be disassembled for maintenance,
- Replaceable inlet valve,
- Replaceable exhale valve,
- Threaded internal exhale valve cover,
- 5 point adjustable head harness, elasticated by stainless wire spring,
- Adjustable nape strap, elasticated by stainless wire spring,
- Neck carry strap.
The threaded lenses;[]
The threaded lenses were of an aluminium frame, and could be easily taken apart for maintenance in case of a broken lens, or in case one needed to replace the anti-fog inserts.
To install an anti-fog insert, the lens frame had to be unscrewed, the triplex glass lens removed, and the insert placed with the coated side inwards on the sealing gasket. Once accomplished, the lens was inserted into the frame, and the frame cap was threaded back on tight as to press the triplex glass lens against the anti-fog insert, and thus pressing the insert against the sealing gasket.
The lenses were made of two glass lenses laminated together, and the sealing gasket of natural rubber. Military kits issued spare gaskets with the spare lenses.
The valve housing;[]
The valve housing was developed by Hærens Laboratorium and modelled after the German Gm.30 first type valve housing's form factor. Production was performed by the Danish metallurgical company UM, and their logo can be found in the exhale valve chamber, and on the exhale valve cover.
The valve housing is comprised of cast aluminium, and is divided into three base parts;
- Inlet valve seat,
- Valve housing,
- Exhale valve cover.
The inlet valve seat is a separate stamped piece that's glued into the mouth of the "inhalation chamber". It features two flat-headed pins which are used to retain the crescent shaped inlet valve.
The exhale valve cover is threaded, allowing for removal of the exhale valve and sealing gasket for maintenance, or installation of a blanking disk to convert it for rebreather use.
The exhale valve is comprised of three parts;
- Aluminium valve seat,
- Tulip valve base,
- Tulip valve top.
During assembly, the tulip valve base and top are vulcanised together by three 'ears', or flanges, combining it into one unit. The now one unit valve is then installed in the aluminium valve seat. With the valve housing itself, the threads are refined, and the inlet valve seat is glued in place. The valve housing gets painted, the inlet is lacquered, the inlet sealing gasket and exhale valve sealing gasket are then inserted. The inlet valve and exhale valves are installed, and the exhale valve cover is threaded in tight to seal the exhale valve. After that, the valve housing would be fitted to a facepiece and affixed by a metal clamp ring.
M. 1938 Civil-Ansigtsmaske manuals depict a glimmer valve and interrupted threads in the diagram, indicating the mask had at some point been intended to use a glimmer valve. Instead, a smaller adaptation of the Gm.24's tulip valve was used.
Variants[]
Arbejds-Ansigtsmaske, Military, Para-military and state issue;[]
The M. 1938 Arbejds-Ansigtsmaske (Work Facemask) was issued to military, para-military and state-owned or related organisations.
Kit:[]
- Facepiece
- Filter
- Spare filter
- Accessory tin
- Anti-Fog inserts
- Spare Triplex glass lenses
- Spare lens sealing gaskets
- Cleaning cloth
- Manual
- Carrying tin
Markings:[]
PLACEHOLDER
CF Refurbished Arbejds-Ansigtsmaske;[]
Civilforsvaret (CF) maintained a stock of all pattern of M. 1938 Arbejds-Ansigtsmaske, but began to favour the M. 1938 G type in black rubber due to examples made of domestic Danish rubber hardening within 20~ years of production. Due to poor Danish rubber, certain post-41 production G types needed new valves. The inlet valves were often sourced as spares from military M/49 and M/49/53 production, but the CF also produced its own tulip exhale valves for both the M. 1938, Gm.30 and Gm.38's, identifiable by a grey colour.
Due to the masks being prone to warping as a result of storage methods, the CF also fitted a pad under the forehead seal to prevent the material around the lenses and forehead from caving inwards. The CF also eventually began colouring the green hardware, painting it grey instead, so as to appear less militant.
Kit:[]
The CF used the M. 1938 for a variety of roles, and as such kits varied. Initially a standard kit may have been identical to a military kit, but later kits for common personnel may have consisted of just the mask, 42mm or 40mm filter (with adaptor), anti-fog inserts and spare lens gaskets, anti-dim cloth or soap, cleaning cloth, manual, and a modified British L1 Mk. I or Mk.II haversack.
Masks may also have been modified for use with rebreathers, as well as being used with 'fresh air devices' which consisted of extended hoses such that one may enter a room whilst still breathing fresh air.
Markings:[]
Same as the initial mask type, but with H.A. or H.t.K. crossed out with black lines.
Civil-Ansigtsmaske, Civilian and commercial issue;[]
The M. 1938 Civil-Ansigtsmaske (Civilian Facemask) was developed with the intent of providing a steady supply of respirators for the civilian populace to use as protection against the potential deployment of war-gas.
For ease and cost of manufacturing, the kit was reduced including the features of the mask itself, as well as using cheaper textiles.
The lenses of the Civil-Ansigtsmaske were of a celluloid construction with aluminium frame and compressed cardboard spacers to protect the plastic during the crimping process while being manufactured. The brass lens frame would be pressed into the faceblank, where the lens itself would then be inserted from the exterior, and a brass wall from the lens frame would then be pressed and rolled over to retain the lens. This resulted in the lenses being static, and thus meant a lack of ability to insert Anti-Fog inserts.
Lens design and the textile used remained the largest simplifications of the mask itself, with the rest of cost cutting going into the kit, offering only three accesories in the form of a pressed cardboard container, the manual and filter. The filter itself being a modified M. 1931 type filter, offering a reduced size.
Kit:[]
- Facepiece
- Filter
- Manual
- Cardboard container
Markings:[]
Markings were laid out differently in accordance to the facepiece. Earlier fabric facepieces and the early G type of Danish rubber had the markings indicated on the mask, with date, maker, model type and designation being on the right cheek. Sizing was indicated on the left of the lower cheek, with an IM stamp in top left side of the temple. On the chin would the serial number be indicated, with the valve-housing maker, UM, being indicated on the exhale valve cover.
With the introduction of the black German rubber in 1941, the black ink markings were moved to the head harness instead, placing the size of the mask on the forehead strap, although some examples still maintain the size stamp on the lower left cheek in addition to the forehead stamp. The IM stamp is moved above the forehead size stamp, with the production year, maker, model name and designation being moved to the forehead strap extension. The serial number is then moved to the base on the left side of the neck carry strap.
Industri-Ansigtsmaske, Commercial issue;[]
The Industri-Ansigtsmaske (Industrial Facemask) was the industrial variant of the M. 1938 and was sold commercially on the market. It was constructed to military specifications, making it higher quality than the Civil-Ansigtsmaske.
Thread adaptor.
To increase compatibility with the industrial market, a thread converter could be purchased with the mask. The thread converter was a simple brass stamping made from 2mm thick stock with four crimps that would be bent over the edge of the valve housing's inlet. The piece would be painted green and lacquered red on the inside of the thread. This allowed the mask to use filters threaded for DIN, as well as other devices such as rebreathers.
Due to the nature of the valve-housing, the design lent itself well to conversions for rebreather use. This would be accomplished with the removal of the inlet valve, and the replacing of the exhale valve with a blanking disc, which was accomplished by gently pulling out the inlet valve and unscrewing the exhale valve cover, replacing the exhale valve seat with the blanking disc and screwing the cover back on.
Some examples may havee affixing valve-housing bands made from a copper alloy, unlike the Civil and Arbejds-Ansigtmaske.
Kit:[]
- Facepiece
- Thread convertor
- Blanking disc
- Filter
- Manual
- Anti-Fog inserts
- Cleaning cloth
- Carrying tin
Markings:[]
Unlike the Civil and Arbejds-Ansigtsmaske, the Industri-Ansigtsmaske has neither a date or IM stamp. It does however maintain the same nomenclature style, size stamps, and serial number stamps, all laid out in the same way as earlier M. 1938 types.
Facepieces;[]
Mask sizes;[]
- especially for kids,
- especially for young people,
- especially for women,
- especially for men,
- Oversized.
(Arbejds-Ansigtsmasker and Industri-Ansigtsmasker were only made in size 3, 4 and 5.)
Facepiece types;[]
- Internally rubberised canvas, 1938 to late 1939.
- Internally and externally rubberised canvas, 1939 to 1941, Gummi type, Brown.
- Internally and externally rubberised canvas, 1941 to 1943, Gummi type, Black.
Filters[]
Two types of filters were developed for the M. 1938; one larger military model, and one smaller civilian model.
Military filter;[]
The Military filter was a large nickel plated steel stamping divided into two base sections. The bottom of the filter has a central inlet hole, and has 12 concaving corrugations to increase rigidity. A U shaped steel wire is welded onto the bottom, to which a piece of twine is tied, which retains the rubber plug, ensuring it doesn't get lost. The first layer is straight walled, and continues up into the second layer, where it continues the straight angle for roughly one centimetre, after which it tapers inwards to funnel inhaled air. Before the top, a retaining corrugation running horizontally around the filter converts the taper into a rounding angle, which then continues as a slight upwards angle running along the top, meeting in the centre to form a male 42mm thread, with which the filter is threaded into the mask.
First layer, bottom: Røgfilter, "smoke filter", for filtering finer airborne particles such as soot from fires, particle based irritants like some tear gasses, and toxic particles. The particle layer consists of a large layered spring, with fine layers of compressed cotton pads fitted inside each coil of the spring, making a stacking effect. This was done to increase surface area. Air is forced to pass through the cotton, filtering out particles. There are roughly 10-11 layers.
Second layer, top: Gasfilter, for filtering various toxic gases and vapours. This layer consists of activated charcoal, and utilises adsorption to rid the oxygen of contaminates.
Each layer is separated by a cotton pad and metal wire mesh. The gas layer also has a grate on top, which helps further retain the charcoal.
Civilian filter;[]
The civilian filter was developed to be lighter and smaller, reducing the burden on the wearer, as well as being simpler to produce. The filter shell was made of steel stampings, and used older late pattern M. 1931 parts to simplify production. The bottom "rain cover" was taken from M. 1931 filter production, as well as the retaining grate for the particle filter.
First layer, bottom: Røgfilter, "smoke filter", for protection against harmful dusts and particles, as well as particulate irritants like various forms of tear gasses or other nauseating materials. The particle filter consists of dense red sponge with small canals and pores to trap particles.
Second layer, top: Gasfilter, for filtering various toxic gases and vapours. This layer consists of activated charcoal, just like military filter, and utilises adsorption to rid the oxygen of contaminates like most other gas filters.
Each filtering layer is divided by a cotton disc, metallic wire mesh and grate.
Similarly to the military filter, the civilian filter had a small bar welded over a stamped in dimple for which a string could be tied, which then would be tied to the rubber plug. This was such that the plug wouldn't get lost, and allow the user to reseal the filter after use in case the filter hadn't expired.
By July, 1939, some 1600 filters had been made.
Containers & Carriers[]
Five types of state made containers were available, depending on the model of the mask. Military masks were issued either in large cylindrical stamped steel and nickel plated tins of three models, or a fabric carrier for the Navy. Civilian masks were sold and issued with a cylindrical cardboard container.
Military carriers;[]
Blikdaase, M. 1938;[]
The M. 1938 Blikdaase (Tin can) was introduced alongside the M. 1938 Arbejds-Ansigtsmaske and was an updated design of the prior M. 1931 Blikdaase. The tin is constructed of thick, stamped nickel plated steel and features two strengthening corrugations. It has an adjustable cotton carry strap attached to the right of the closing clasp, as well as a leather strap by the bottom to secure the tin to the uniform's belt. The lid is attached by a hinge on the back of the tin, and is held shut by a clasp. In the lid, a retaining spring is present which retains an accessory compartment which may be removed. The accessory compartment is of a steel stamping shaped similarly to the filter with a circular extension on the top for storing spare lenses, spare lens sealing gaskets, anti-fog inserts and a spare filter.
"H.A. M. 1938" is stamped into the lid by the edge facing the clasp, as well as "H.t.K. Arbejdsmaske" being written above the stamp.
Blikdaase, M. 1938/39;[]
The M. 1938/39 Blikdaase was designed to reduce the weight and cost of the M. 1938 Blikdaase, and did so by using thinner steel. To make up for the reduction in strength, two additional corrugations were added, resulting in four total. The tin is otherwise identical with the exception of markings.
"H.A. M. 1938/39" is stamped into the lid by the edge facing the clasp, as well as "H.t.K. Arbejdsmaske" written above the stamp.
Blikdaase, M. 1943;[]
The M. 1943 Blikdaase was of an entirely different design, copying the German M.34 tin, particularly the Luftschutz model, which had the benefit of being much smaller than prior models. However due to the size reduction, the tin also had no provisions for a spare filter, although it did maintain a compartment in the lid for the manual and a sleeve containing spare anti-fog inserts and lens gaskets. The tin is ordinarily paired with an M. 1938 G Arbejds-Ansigtsmaske in black rubber, with military pattern filter. Due to the army being dissolved by the German occupants on the 29th of August, 1943, these tins remained largely unused until the post-war period.
"H.A. M 1943." is stamped into the middle of the lid, with the H.A. often being striped over with black paint.
Sejldugstaske M. 1938;[]
The Danish Royal Navy was displeased with the M. 1938 tins due to their weight, bulk, and susceptibility to corrosion. This lead to the Navy placing an order for special fabric carriers to reduce weight and increase manoeuvrability in tight quarters. The carrier was a tall oval shaped fabric bag with a main compartment for storing the mask, and used a tab with button for closing the bag. Inside the main compartment would be a pocket for spare lenses, spare lens sealing gaskets and anti-fog inserts.
The carrier had a shoulder strap and waist strap of the same pattern as the preceding Sejldugstas (sailcloth bag) used with the M. 1926.
Civilian carriers;[]
Papbeholder;[]
The Civil-Ansigtsmaske was sold in kits, including the "Papbeholder" (Cardboard container), which was of pressed and moulded cardboard. It had two holes in the lid and a nut on the bottom to accommodate an optional carrying twine, or carrying strap. The lid also has a stamp indicating mask size.
"H.t.K. Civilgasmaske M. 1938" is moulded into the cardboard container. The lid of the container is also stamped with the size of the mask.
Blikdaase (third party);[]
Third party containers were also available, most of which being made of sheet steel with stamped in corrugations, rolled and soldered in the back, with stamped steel lids. They were often D shaped, and had a spares holder in the lid.
Private civilians also made their own custom carriers. This is similar to the British General Civilian Respirator, or the German Volksmaske series, where both encouraged citizens to make their own carriers.
History & Use[]
The M. 1938 platform was introduced too late to see any significant military use before the war, but was still successful among paramilitary organisations, civilians and industry. The C.B. (Civilbeskyttelsen - Civil Protection) was the predominant stately user of the military specification masks, issuing it as standard equipment. The masks were also maintained in inventory by police, but were often sold by firefighting organisations which themselves used them, and equipment vendors, such as Falck, Zonen Redningskorps and H. Meisner-Jensen. Vendors such as H. Meisner-Jensen and Viggo ARP, and other industrial equipment vendors also sold the M. 1938 Industri-Ansigtsmaske in either official kits, or kits assembled by them.
Various stores also started carrying Civil-Ansigtsmasker, and official 'equipping points' began to appear, whose purpose was to provide easy access to protective equipment for air raids, both for civilians, but also volunteers such as 'House guards', who upon becoming a member of the house guards organisation would gain a coupon for one free M. 1938 Civil-Ansigtsmaske. Due to its comparatively low price at only 10 DKK, the M. 1938 Civil-Ansigtsmaske was by far the most affordable option available to civilians, while also being offered in the largest size range. With its low price it also became popular among industrial workers or others who needed protective masks on a budget. As such kits with industrial accessories began being sold as a budget offering.
Militarily the M. 1938 did see use in Finland under the D.F.K. (Danish-Finnish Corps) who raised roughly 1000 volunteers during the Winter War, bringing with them one M. 1938 Arbejds-Ansigtsmaske kit for every volunteer. However the D.F.K.'s training took too long for them to see any combat before the end of the winter war.
Post-war the M. 1938 also saw military use. They were predominantly issued during the military's reconstruction in the mid-to-late 40s and until the 50s. Most use seen thereafter was by the CF and other smaller civil defense organisations, as well as private companies and civilians.
References[]
- Military Equipment of the 20th Century - https://m55q.weebly.com