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This site is intended to give basic information on the steam condensing chest. The water-cooled machine gun came into wide use during WWI with the introduction of the German Maxim. The end of WW2 brought the phasing out of the heavier weapon in favor of lighter air-cooled versions. During this relatively short period of time designs sprung up in many countries, and along with them the steam chest. Ideally a water-cooled gun would have a water circulating unit which kept a large volume of water moving through the water jacket. This system also kept steam contained which might give away the gun's position. In the field, however, this cumbersome apparatus was impractical. Instead of the circulating unit the steam condensing chest was employed. This allowed for the recovery of potentially scarce water, as well as helping to conceal the steam cloud. Where practical, a water can was carried. This can looked like an enormous Boy Scout canteen. Worldwide, the variety of steam chests manufactured during the period of the water-cooled machine gun is daunting. I have included photos of a few of these.

I have credited photos where possible. If you know the source of any uncredited photos, or feel any have been used improperly, please E-mail me. Images will enlarge if you click on them

Above, from left to right: Series 1, series 2 (M1) & Series 3 (M1A1). Above right are the bottoms, showing the series 1 with its distinctive plain bottom, and the series 2 & 3 which have skirts to protect drain plug from damage.
The water chests designed for the Browning series water-cooled machine guns had a drain plug on the bottom. The series 2&3 cans had a recessed bottom to keep this plug from hitting the ground. The series 1 can did not. Usually the series 1 can is shown leaning against something, often one of the front tripod legs as shown in the photo below. The other photo of the series 1 can I have included because it is the only image I have run across which shows the early leather funnel used to fill the water jacket.

Photo: BMG Parts

The red arrow indicates the leather funnel.

Left: Another variation of a Series 1 chest with a smaller handle and different treatment of the recess.

Right: The drain plug of the Series 1 chest shown at left.

The leather funnel is shown as an accessory in Colt Automatic Rifles and Machine Guns. I don't know if this was adopted by the military or was a commercial product.

Photo: Rick Shab

Photo: Rick Shab
The series 2 steam chest maintained the handle on the closure, but had a recessed bottom and top. The small arrows on the closure and the top of the can must be alligned or the handle, which makes only 1/4 turn, will end up aligned front to back instead of side to side.

Photo: Library of Congress

Drain on the M1.
The series 3 chest had a heavy canvas strap handle. Since this is the style steam chest I own, it is the one covered in greatest detail. I have included photos and dimensioned drawings. To see them, click on the image below, right.
Link to photos and drawings

Drain on the M1A1.

Condensing hose attached to water jacket of a Colt M37.


A water circulating unit attached to
a Colt MG-38.

The Colt Commercial steam chest and condensing hose.
Thanks to Dave West for these excellent photos of a Colt Commercial steam chest.
Left and above are large canteens that were used for carrying extra water.
Thanks to David Hayes for the center photo showing a nice pair of canteens.
I am including a few steam chests from other countries and for other types of machine guns.

Another Vickers

A Vickers with its signature Shell Oil can.
Source: brassmagnet

The standard chest for the British was a British Shell motor oil can.

Clamp end of a condensing hose. The other end is plain rubber.

An early Maxim with it's
round steam chest.

Steam chest for Swedish
Browning Kulspruta.
Twin Colt MG-52 water-cooled MGs with a circulating can and pump.
Russian 1910 PM Maxim with steam chest.

FIAT-Revelli MG with water chest.
This chest circulated the water.

The Schwarzalose had a very large can
which also had a compartment for the hose
The two photos above are form
Ian Hogg's Machine Guns.