How to identify an M-1 liner?

Dive into the heart of the US Army's iconic equipment! Since 1941, the M1 helmet has made history, not only with its robust steel shell, but also with its essential interior element: the M-1 Steel Helmet Liner. This removable helmet, designed to be worn alone or under the main shell, offers unique tactical flexibility that made it an essential piece of equipment for the American soldier during World War II.

A Little Flashback: The Genesis of the M-1 Liner

In 1940, the U.S. Army was still using the M-1917A1 helmet, a derivative of the British helmet. However, the latter proved unsuitable for modern combat, as it did not provide effective head coverage and could impede soldiers' vision on the battlefield.

Faced with this observation, the US Army entrusted the development of a new military helmet to Colonel HG Sydenham. To design a more ergonomic model, he drew inspiration from civilian helmets, particularly those used in American football. The idea was to create a two-component system: a lightweight M1 liner with suspension, designed for comfort and support, which would be integrated into a steel shell providing ballistic protection.

Riddell, the patent holder for this design, was chosen to produce the first prototype, dubbed the TS-3. This revolutionary design would lay the foundation for the M1 helmet and liner, used by the US Army from 1941 and throughout World War II.

The Liner Fiber Helmet M-1: The First Models

In order to launch mass production of the new heavy helmet and its liner, and after purchasing the patent from the Riddell firm, the American army decided to launch a call for tenders.

Mc Cord Radiator & Manufacturing Co, which was already producing the M-1917A1 helmet for the army, decided to partner with Hawley Products Company to offer the production of liners.

Hawley Products Company, which manufactured tropical fiber helmets for the military, proposed an liner made from compressed fiber.

This prototype was quickly approved by the army and the first series of nearly 1,000,000 helmet liners was launched in 1941. In total, nearly 4,000,000 examples left the factories of McCord-Hawley and its subcontractor, General Fiber Company. The design of this model was stopped in 1942, with the introduction of a new plastic model.

Orders Fulfilled by the Quartermaster Depot in Chicago

1st type in compressed cardboard

The liner produced by Mc Cord-Hawley was in its design very close to what was already in place for the development of the tropical helmet.

The process was accomplished by gluing together two pieces of compressed cardboard fiber, each soaked in a waterproof substance and covered with fabric. The suspension structure, originally developed by Riddell Co., was made by assembling white rayon canvases, secured with riveted rectangular retaining plates.

The brown leather chinstrap of the liner was also riveted directly to the inner side sections, which made it impossible to remove it if necessary.

A canvas strap is attached around the entire circumference of the helmet with 6 rectangular brass rivets. Three straps attached with the band and its rivets form three "Vs", the ends of which are connected in the center by a cotton lace, so that the depth of the liner can be adjusted.

The canvas headband is fitted with a second leather headband attached with six snaps. On this first model of liner, the headband was not adjustable and was available in 13 different sizes.

2nd type in compressed cardboard

The second model in compressed cardboard corresponds to a production between March 1942 and August 1942. The first type of rectangular counter-rivets was replaced by steel models in the shape of an “A”.

The straps that make up the inside of the helmet were also changed, made of OD#3 colored cotton. The inner strap was also changed to allow for head size adjustment. This second type made of compressed cardboard marked the end of the manufacture of liners with this material, which was considered far too fragile.

Liner Helmet M-1 New Type: The Age of Plastic

It was from November 1942 that the Liner Fibre Helmet M1 was judged as Limited Standard (production and distribution stopped until stocks ended).

It was at this point that the Army issued a new request for proposals to manufacture more durable and faster-manufactured liners. An order was placed with the production of nearly 600 high-pressure molded liners by three companies specializing in civilian helmets (Inland Division, Mine Safety Appliances, and Westinghouse Electric Company).

The QMC (Quartermaster Corps) approved the project in February 1942 under the new name "Liner Helmet, M-1 New Type." As the war raged, orders were placed with three companies (Inland Division, Mine Safety Appliances, and Westinghouse Electric Company).

On the other hand, the firms Saint-Clair Rubber Company and BF Goodrich Company – Hool Rubber Division, proposed a low-pressure molded model.

Between July 1942 and August 1945, the Westinghouse firm manufactured no fewer than 5 variants of high-pressure liners, combining different interior suspension systems and materials.

Hallmarks: Identifying Your Liner Manufacturer

To find out which manufacturer produced your helmet liner, simply look at the bottom, under the cord that connects the V-shaped straps. You should see a stamped logo. Compare it to the various manufacturers listed here to identify the company.

Hood Rubber Co Liner Helmet M-1 New Type Low Pressure	Saint Clair Rubber Co Liner Helmet M-1 New Type Low Pressure
Westinghouse Mfg Co Liner Helmet M-1 New Type High Pressure	Seaman Paper Co Liner Helmet M-1 New Type High Pressure
Capac Mfg Co Liner Helmet M-1 New Type High Pressure	Firestone Tire Co Liner Helmet M-1 New Type High Pressure
Mine Safety Appliances Liner Helmet M-1 New Type High Pressure	International Molded Plastics Inc. Liner Helmet M-1 New Type High Pressure
Inland Mfg Div Liner Helmet M-1 New Type High Pressure

Manufacturers' logo

Here is an infographic version of the logos of the various US high-pressure liner manufacturers during World War II.

High Pressure Liners: Production Statistics

Counter Rivets: A Key to Dating

One last way to best identify and date your liner is to look at your rivets. These metal parts tell you a lot about the manufacturing date. Depending on their shape, the material used, and the paint applied, you can estimate the production date of your liner.

Below is a table that lists the different elements related to the manufacturing date of your liner.

Conclusion

Several factors can be used to date a helmet liner. Whether it's the materials used to make the helmet, or the various components that make up the interior and its suspension lines, it's relatively easy to estimate the liner's manufacturing date. Not to mention the easily identifiable stamp on the bottom, on the inside.

Given the manufacturing activity during World War II, there's a good chance your helmet liner was produced by Westinghouse between 1942 and the end of the conflict. Of the nearly 51,000,000 units produced, Westinghouse produced no less than 45%, or nearly 23,000,000.

Need help dating or identifying your Liner M-1?

If you have any difficulty dating and identifying your liner, please do not hesitate to contact us , we will be happy to help you. At Mon Casque M1, we are here to support you in your passion for WW2 militaria and the customization of your US M1 helmets!