Have a look at drawing 2103. External.So went to add in the flange on the part that goes over and around the tunnel and have run into a discrepancy in my cad model.
The question is, do I make the central tunnel 2.75” internal width or external width. I’d previously had it as an internal dimension, but now I can’t remember why I decided that. It’s been so long since I drew that part of it.