M1 Helmet

The M1 Helmet without any lining or net

The M1 helmet is a combat helmet that was used by the United States military from World War II until 1985, when it was succeeded by the PASGT helmet. For over forty years, the M1 was standard issue for the U.S. military. The M1 helmet has become an icon of the American military, with its design inspiring other militaries around the world.

The M1 helmet is extremely popular with militaria collectors, and helmets from the World War II period are generally more valuable than later models. Both World War II and Vietnam era helmets are becoming harder to find. Those with (original) rare or unusual markings or some kind of documented history tend to be more expensive. This is particularly true of paratroopers' helmets, which are variants known as the M1C helmet and M2 Helmets, which used special liners with multi-point retention straps to prevent undesired movement of the helmet during descent.

## Description

The M1 is two "one-size-fits-all" helmets—an outer metal shell, sometimes called the "steel pot", and a hard hat–type liner that is nestled inside the shell and contains the suspension system that would be adjusted to fit the wearer's head. Helmet covers and netting would be applied by covering the steel shell with the extra material tucked inside the shell and secured by inserting the liner.

The outer shell should not be worn by itself. The liner can be worn by itself, providing protection similar to a hard hat, and was often worn in such fashion by military policemen, Assistant Drill Instructors (known as AIs), and rifle/machine gun/pistol range staff, although they were supposed to wear steel at the range. The liner is sometimes worn in U.S. military ceremonies and parades, painted white or chromed.[citation needed] The depth of the helmet is 7 inches (180 mm), the width is 9.5 inches (240 mm), and length is 11 inches (280 mm), the thickness is 1/8" (3 mm), The weight of a World War II–era M1 is approximately 2.85 pounds (1.29 kg), including the liner and chinstrap.

The metal is a non-magnetic Hadfield manganese steel for M1 helmet shells were smelted at the Carnegie Steel Company or the Sharon Steel Company of Pennsylvania. After being poured into fifteen-ton ingots (also called "heats"), the steel was divided into 216-inch by 36-inch by 4-inch blocks, known as "lifts," which were then cut into three equal 72-inch pieces to make them easier to handle. The cut lifts were sent to the Gary Works in Gary, Indiana for further processing, after which they were each reduced into 250 68-inch by 36-inch by 0.044-inch sheets, which were cut into 16.5-inch circles. The helmet discs were oiled and banded into lots of 400 for delivery by rail to McCord or Schlueter for pressing and final assembly.

Each "heat" of steel was assigned a unique number by the smelter, as was each of its "lifts." When each new heat was unloaded at McCord or Schlueter, it was assigned a sequential number, and each lift within the heat was assigned a letter of the alphabet (for example, the third lift unloaded of the forty-ninth heat received by McCord would be 49C. This unique "lot and lift" number was stamped onto each helmet produced from the discs of a particular lift, and allowed for traceability in case the helmets exhibited defects. The "lot and lift" number is in reference to the time when the fabricator received the helmet discs, not when they were made into finished helmets. Lifts of heats were not loaded onto or unloaded from railcars in any particular order, and were often warehoused (also in no particular order) before being finished.

The helmet discs were drawn to a depth of seven inches to create the rough helmet shape, or "shell," and the edges were trimmed. The edge of the shell has a crimped metal rim running around it, which provides a smooth edge. This is usually known as the "rim". The rim has a seam where the ends of the strip meet. On the earliest shells the seam met at the front. This was moved to the back of the rim in November 1944[8] At this time, the rim also went from being made of stainless steel to manganese steel. On each side of the shell, there are stainless steel loops for the chinstrap. Early World War II production shells had fixed, rectangular loops, and mid-war to 1960s helmets feature movable rectangular loops. This feature was adopted in 1943 to address the problem that when earlier helmets were dropped, the fixed loops were more susceptible to breaking off. Early shells for paratrooper helmets feature fixed, D-shaped loops. The shells were then painted with flat olive drab paint, with the paint on the outside of the shell sprinkled with either finely ground cork (World War II era) or silica sand (postwar).

World War II-production helmets feature sewn-on cotton web olive drab shade 3 chinstraps, replaced gradually throughout 1943 and 1944 with olive drab shade 7 chinstraps. 1950s and later production chinstraps are made of olive drab webbing attached to the loops with removable metal clips. Nylon chinstraps were introduced in the U.S. military in the 1980s. These straps featured a two-piece web chin cup and were fastened by a metal snap rather than buckle.