I've attached a poor pic of the tank mounted. Hopefully you can see how the tubes run.
I made a down & dirty tube beading tool, which did the job. Pic attached. The tiny wheel on the end of the top arm is free to rotate. Two follower rollers allow for the bead to form. Tighten C clamp a bit at a time when rotating the tube. Works on thin wall alum tubing.
The fill tube and the larger oil return fitting on the tank were made from 1-1/4" rigid alum electrical conduit (nominal diameter 1.66"), turned on lathe.
The conical section on the fill tube was made from sheet alum, cut and bent to form the section, then welded.
I did not previously say, but the oil tank is a purchased kit. It is probably heavier than needed, but our project purchasing group did not always seek out the optimum solution. Sorta, just get it done. I think the filler cap was part of the kit.
Also, there is a level dipstick (made from automobile windshield wiper metal strip) attached to the filler cap. One of the small fittings on the top of the tank extends down into the bottom sump. All other fittings are welded flush to the tank wall.
We fill the tank about half full for operation, maybe 3 qts., not sure.
