I ordered two things - a chunk of 4.25" aluminum round cut-off, and a rotary table (needed to cut the bayonets in the lid so it would lock down). I turned it oversized according to the dimensions from the existing lid, drilled a through hole it (so I could thread in a rod and hold it up (hang it).
I then marked a groove (for concentric attachments, drilled 120-degree-apart holes, then tapped them with a pipe thread. That allowed me to simply thread in the brass pipe inserts.
The hardest part was putting the bayonets on the bottom lip. There were six of them, so I HAD to have a rotary indexing table.
First, I used a boring bar to cut it to a solid lip on that bottom inside edge. Next, I had to mill out between the bayonets. This is what required the rotary table. I threw a collet into the spindle with an end-mill, positioned it for a cut, then simply milled the lip off to get a bayonet.
Then I assembled it into a functional brake bleeder :
While I was at it, I had a neighbor who needed a thumb screw for a photography gimble. So, I cut two of them :
Now I can get back to work on the corvette!