Conceptually pretty simple.
It is 2 rings - one aluminum and one acrylic. The electronics are glued down to the aluminum ring with silicone heat sink adhesive (from DX). The outer edge was cut on a metal cutting band saw. I drilled a hole in the table as a pivot point for each piece and cut them with a 1/2" blade (this is about the limit for minimum radius for that blade. The center hole was cut with a 4 1/4" hole saw. Holes in the plastic for the LEDs and regulators were cut with oridnary forstner bits - just go slow. The holes for hte screws were gang drilled. DO 2, tap and insert the first 2 screws (6-32x3/4). Then drill the rest. Next grab a beer and the tapping jig and carefully tap the other 22.
Everything was cleaned up on an oscillating spindle sander. The outer edge of the plastic was painted white to not waste the light.
Once it is wired up and test fitted, a thin bead of pure GE silicone adhesive (clear) is applied wiht a hypodermic syringe all the way around all of the openings. The light is assembled and slowly and evenly clamped down (4-6 passes on all of the screws).
The led are in 2 stings - effectively right and left. The switch is DPST center off. one way lights the right string only, and the other lights both.
The canister is the same for my other lights 12v 4.5 AH NIMH battery pack in 2" PCV schedule 40 pipe. This way all 3 lights have interchangeable packs (my primary, my wife's and the ring light).