Here a few shot of some custom tubes that I had made.
These were made from a mag D cell flashlight for prototype purposes.
I use one for survival items and the other for first aid items.
Custom aluminum tube
These threads were cut on a manual lathe.
Each cap has an o-ring which make the tube water tight
(I have tested to the depth of my bath tub
for over ten hours - dry as a bone inside).
I liked these so much I decided to commission a run of some tubes of my own design.
Here are some initial 3D renderings of my design. Material for consideration is 6061 Aluminum.
Tube - view 1
Tube - view 2
The caps will thread down onto the tube and will be sealed with an o-ring.
Cap - view 1
Cap - View 2
Cap - View 3