I see that the 3-in aluminum enclosure is bored to a specific ID, yet the cast acryllic tub ID appears (in the drawing) to be “as cast”; however, both can use the same aluminum O-ring flange. From what I have read about cast acryllic tube, there is typically a tolerance of +/- .020in on the wall thickness. So my question is: do you bore/ream your acryllic tube’s ID to a tighter tolerance than its raw cast state to ensure a consistent fit for the aluminum o-ring flange? (I ask because I am designing a coupling to mate a BR aluminum tube to a BR acryllic tube and would like to use the o-ring groove dimensions of BR’s O-ring flange (since I know they work!).