I don't mean to derail this thread but; I was thinking of Vent size recently and decided to try and determine the general dimensions through photogrammetry. Probably a little late for this build but this may benefit others here.
Given I had already modelled the Panther deck in CAD, and using as many decent photos that I could find of the vents, I pulled what I would consider a rough but still fairly reasonable solve by matching the result to the Panther part as best as possible.
(Above) photogrammetry solve using available pictures.
(Above) Panther upper deck CAD model, with early vent geometry derived from result.
(Above) Final vent model and panther deck aligned to result in CAD.
(Above) Closeup of the top lip of the vent.
Interestingly the top outer rim seems to be close to if not 3.75" exactly. Hence in most instances I have rounded to imperial fractions given that it was most likely drawn from these. Maybe...
The top lip seems straight with no taper. The middle chamfer is at approximately 25 degrees, and the lower section I originally thought was angled outward but I have decided that it is most likely vertical and probably turned parallel on a lathe if not found from a kit....
The opening exposing the koolshade has an inner diameter of 3.188". This top cover disc which holds the koolshade in place I have modelled at 0.040" or 1mm.
It goes without saying that I would be curious as to what others have determined for the size of these pieces but hopefully I think this is a good starting point.
end of rant...
Bjorn
EDIT: After much research and new photogrammetry solves I feel these dimensions shown above are oversize in both diameter and height. Eagle1's OD of 4" is more accurate if not spot on. More to follow...