Home About USS Squalus About the diving operations Manufacturing the helmets Part machining & finishing Sub-assembly fabrication Final Assembly Progress Updates
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To the best of our knowledge the helmets used on the Squalus were prototypes. We have been unable to find any good photos or descriptions of the Helium helmets used. The Mark V Helium helmets we are producing are the production models shown on the 1942 U.S. Navy BuShips drawings. The original standard Navy Helium helmet design had a exhaust tube which wrapped over the helmet and terminated in a perforated bulb like the Mark V banana tube. In the 1950's the design was modified by shortening the exhaust tube and adding a double exhaust on the top of the helmet.
We will be following the 1942 USN Helium Helmet Assembly drawing from our files.
Making a diving helmet is a time consuming and labor intensive process. The photos below will illustrate some of what goes into the production of these helmets.
Note: Not all the photos below will be of the actual 26 Helium helmets. Existing Mark V manufacturing photos will be used where they illustrate a part or operation.
Parts
You can't build anything without the correct parts. Some parts we purchase "off the shelf", some we subcontract, and some we make in house. The U.S. Navy Helium Helmet has over 210 parts. A DESCO diving helmet (Mark V, Helium, Commercial, or Air Hat) is made up of various parts from many sources. Heavy and massive parts are generally cast from Red Brass by a local foundry. Lighter more detailed or precision parts are made on our machines by us, or sub-contractors with equipment which can make them more efficiently. Standard hardware (wiring, speakers, nuts & bolts, etc.) are purchased from industrial supply houses. Stock materials such as Acrylic for the windows, Yellow Brass for turned parts, Rubber and Leather for gaskets are all sourced locally. Every part on a helmet has some value added labor done to it before it is installed.
Cast parts are made from DESCO's patterns. The foundry places forms over the patterns and rams sand until it takes the shape of the pattern. In areas of the final casting that need to be hollow, cores made of fine sand are inserted. Molten Brass is poured into the mold to produce the parts.
On 5/30/07 we received 1600 pounds of Red Brass castings from the foundry. The parts included canisters, breastplate base rings, neckring sets, window bases & guards, canister elbows & aspirator bodies, breastplate loops, and telephone cups. This is the first of several casting orders and represents about 40% of the castings to complete this project. The cast parts require some machining. They also must be sanded and buffed.
The helmet shells are spun by an outside supplier. Copper sheet is rolled around a form on a special machine which resembles a lathe.
Turned parts are machined from rod or hex Yellow Brass bar stock. These parts include breastplate studs, front door toggle bolt, canister nuts, canister sleeves, exhaust stem, exhaust bonnet, and Non-return parts.
Once those operations are completed the parts will be stored in our parts racks until needed.
Machining Parts
Whether cast or brass stock the parts require machining. This could entail drilling and tapping holes, single pointing threads, cutting to size, or just making a clean surface.
Finishing Parts
Many of the machined parts still need sanding and buffing. Some cast parts don't require any machining and only need some fitting, then sanding, buffing, and polishing. The brails are a good example of these type of parts. The bonnet shells sometimes need to be sanded a bit to seat properly in the neck ring. The bonnet lip is sanded and buffed like the cast parts
Assembly
Once you have the parts you need they must be assembled into the finished product.
