Prototype #4: The Last One?

After a long overdue wait I finally have the pieces of prototype #4 in my hands, ready for assembly, and they are looking great!

Fresh from the Shop and Looking Good!

Prototype #4 has a number of design changes from the previous prototypes originating from a variety of tests, feedback, and research:

• Magnetic base and cap (it works very well...not sure how I overlooked this design initially)
• Slightly longer for a combination of aesthetics and to hold long-style USB boards if I ever need to
• Hole in the cap for a lanyard attachment
• Slightly simpler interior design for cheaper production (at a small cost of strength)
• Very high strength materials (Aluminum 7068-T651 and Titanium Grade 5)
• Hard anodized Aluminum (dark red)
• Laser engraved logo and serial number

Close-up Showing the Laser Engraving Details

The production itself was basically flawless with only a few minor issues encountered:

• Thread in base was 0.05" deeper than specified (makes assembly a little trickier)
• Threads in the Aluminum base were a bit tight (re-tapped manually after anodizing)

Other than the smaller quantities (10 Aluminum and 5 Titanium) the production process was identical to that of the (hopefully) eventual larger order. This minimizes any surprises and gives me a good idea on the base material cost and time required for assembly.

All that is left now is the final assembly of the USB boards and epoxying before I can get back to destructively testing a few units for fun!