Home About USS Squalus About the diving operations Manufacturing the helmets Part machining & finishing Sub-assembly fabrication Final Assembly Progress Updates
Preparation
We pick up where we left off in Sub-Assembly. After plating the bonnet and breastplate neck rings must be lapped to remove excess plating and assure smooth joining. Excess plating in the neck ring threads can jam the bonnet and breastplate together without warning as the excess plating can ball up and wedge the threads during assembly. Lapping the threads is done using commercial valve lapping compound and working the bonnet and breastplate threads together.
The neck ring gasket is sized to allow the proper alignment of the bonnet and breastplate, and provide the necessary seal. Sizing is accomplished by removing Leather, by scraping the gasket, until the desired thickness is achieved.
The sub-assemblies are now ready for fitting out. Each sub-assembly will receive all the "loose" parts that are required, and the tags will be installed on the breastplate.
Bonnet
Now the bonnet will receive the Acrylic windows and guards. The windows are glazed in using Litharge, a Lead Oxide compound.
The exhaust valve stem is lapped to the body to ensure it seats properly, then the exhaust valve assembly is installed.
The transceiver and telephone elbow contact assemblies are installed and tested.
The Non-Return Valve is installed.
Next the High Pressure injector assembly is installed. The Discharge Nozzle will be shipped loose as it is in a exposed position without the canister installed to protect it from damage.
Breastplate
The brail studs are chased with a die to remove excess plating.
The lock latch is riveted to the lockstop, and the drop pin and chain are installed.
The tags are installed.
The brail Copper washers are put on, the brails are installed, and the wingnuts are installed.
At this point the helmet is complete. It will receive a final inspection and then be boxed for shipment.
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Number 01/26 is returned from plating and final assembly has begun. Finishing this helmet will be held up until the Sterling Silver tags are received. Until it is completed it will reside in the display area of our office.
The Copper Disk is a label on the lower part of the Canister. It identifies this Canister as belonging to helmet 01/26.
Look at the photo of the back of the helmet just above the center Brail Stud.
Squalus Helium 1/26 on temporary display in DESCO's helmet collection.
