So the case arrived ahead of expectation today and things have progressed!
Here is the case:
The plastic inserts which hold captive nuts just pop off with a knife:
And here is the NUC just popped into the back of the case (it does not go all the way due to the white plastic power socket).
So I did decide to shave it down to size following the advice from Kiwi:
By this stage I was thinking that the idea of keeping the stock cooler was not the greatest one, as the height is just too marginal, so I was looking at how the cables would be accessed from underneath.
Sata connectors, even slimline ones, just would not have easily fit the other way up as they would sit even higher than the white power connector, and force the board to sit at a strange tilted angle. So I think this configuration will work better. In this configuration of course, they can stick up as they extend into the space left by the Mac Mini base cover.
So I think that the NUC will fit better in the case with the CPU on the top side - obviously though this won't work:
A blower needs to access cool air from somewhere and as the fan would be jammed against the roof, it just isn't gong to happen…...
So I took off and dismantled the original cooler with a view to seeing if the base of the cooler might be suitable to form the base of a new home brewed passive arrangement:
The "fins" of the heatsink had to be pulled off with pliers! and left this behind them:
So it was then a case of cleaning up the base plate to make it the starting point for a new passive heatsink:
Where the fins had been, heat from a heat gun loosened the solder and they could be removed, leaving a layer of solder:
and when that was cleaned off I am left with something that looks good enough for me to work with:
I then took a copper 3mm plate I have and drilled it to match the screw pattern of the base plate:
and that is where I am at right now.
The plan from here on is to use thermal adhesive to attach the 3mm plate to the original cleaned up base plate and use that as a heat spreader. This will then contact with a similar 3mm plate that I will fix to the inside of the Mini casing.
The reasons for the holes in the plate are to be able to access the heads of the fixing screws - which when the plate is glued in place will then be "captive" - so the holes will let me remove the assembly from the processor/board.
I've also made some initial designs for a motherboard tray.