I decided to make this about a year ago and finally got around to putting it all together. My grandfather gave me the old rusted and corroded shell back when I was a teenager and it sat in a box for many years. I think this looks better.
You can see here some of the details of the 40mm shell. Date stamped 1942. Also, it very conveniently had a threaded primer which was already removed. This made it a lot easier to run the wires for the lamp.
Removing 70 years of patina and corrosion wasn't fun. I started just using Brasso and that did ok but I wanted a high shine. I read some tips online and gave it a bath in boiling vinegar. Worked like a charm. Also, on the left picture, Coke can for scale (all out of bananas).
I didn't think about making this post until I had already started. But here are the 5 square pieces I cut for the base and 1 round piece to sit atop the bofors shell. The top three have a 3/8" hole drilled in the center that is the same size as the threaded pipe that came with the lamp kit. The bottom two have a 22mm hole to allow a washer and nut to be added to hold the shell and pipe in place, and then have space to route the cord.
I live in Japan so I'm not sure what name the stain was. I just chose based on color and use a high gloss polyurethane finish. Two coats of stain followed by two coats of poly.
I glued the five boards together and let them sit for about 24 hours with a couple of heave barbells on them.
Here you can see where the threaded pipe extends out of the bottom, secured with a washer and two nuts.
I couldn't be happier. It may not be professional grade, but it means a lot to have a keepsake from my grandfather where I'll be able to see and enjoy it. Thanks for looking!!