I printed an ABS template for the bolt pattern (Legs, through Shoulder Flanges to Frame) which I used to transfer the center points for the bolts which are evenly spaced on a 5” radius. The Legs were drilled out on the Drill Press, using some jigging to keep things square and true. The bolt holes were counter-sunk on the outside surface. I also used a 2.5” Hole Saw and my Plunge Router for the clearance hole for the Shoulder Hubs, which should really have been done before the glue-up of the pieces.
I determined that the Shoulder Flanges (between the Legs and the Body/Frame) would need to be 30mm thick. I cut four discs from the Birch Plywood, two each @ 12mm and 18mm. I made these disks a perfect 6.6” circle on my Router Table, then laminated them in pairs with glue and clamps to form the flanges. After drilling the bolt holes in the Flanges, I wrapped them with strips of flashing to give them the look of milled aluminum. I cut these strips to length and where the ends came together I secured them with a couple staples to hold them while the epoxy I had applied cured. I positioned this point so that it would be at the bottom of the flange, and hopefully out of sight when attached to the legs.