I had big problems on this one. First I totally messed up the milling. I didn't get it centered in the block and by the time I cought it it was to late.
I continued as I had a plan to make use of it anyway which was to just forget the O-ring and make the mounting holes in the top and notch out a spot in the side for the bolts to fot through as they will be sticking half out of the block.
Well that was all fine and dandy untill I realized I put the damn mounting holes in backwards. The block will only fit on one way and I did it wrong. The notch on the left side should be at the lower end and the notch on the right side should be on the upper end. I decided to do it over right. So thisone will probably end up either in the reject pile or I can still use it as a NB cooler on a standard board.