Hi
@Thick8
I can upload pictures here. They will come in the next few days, as I am currently on the road to assembly. In the case of my nephew, these are the same, only for 120mm fans the hole diameter is even smaller.
Don't take it badly, but in the product description and in the technical data sheet the fan mount is 140mm and not the hole diameter. If the hole diameter was 140mm, how would you like to mount the fans?
This is not possible if the diameter is the same as the fan size, because then the circles are together at the cutting points and therefore there would no longer be any sheet metal where the fans are placed and fastened.
In addition, as already written above, the sheet metal is there to ONE seal the fans at the corners so that the air is pressed better through the radiator, and SECOND to stabilize the fans or do you want that when the fans have a pressure build up so that they bend away from the radiator.
Not all fans are like yours, most of them have rounded corners, and the frame may be a bit thicker, which makes the rotor smaller. On yours, the corners are normal corners and the frame is visually quite thin. I also use 140mm fans, but the rounded corners make the frame thicker and the rotor smaller. My frames are 1cm thick, so the rotor only has 120mm, roughly speaking.
I mounted 6 pieces on radiators, and so that they are sealed at the corners I also use shrouds. And 3 case fans, and with these the case has either a grille with or without a dust filter.
I can understand that in your case the rotor is probably a bit bigger than the hole in the sheet metal, but that can't be avoided.
Best Regards