Emc2-
I removed the top and took measurements all around the copper base and found only a variance of .003" with a micrometer. That is very, very good.
The reason for the variance was pointed out by DigitalChaos correctly which is caused by the amount of torque placed on each set screw.
Of course now that I removed the screws and measured I have discovered a vertical fracture along one of the screw holes.
This does not surprise me in the least since there is barely a 64th of an inch of material between the screw's countersink hole and the edge of the plastic. There is no support remaining.
I don't want to be critical, since I have never built a block, but I think it would have been wise to have designed this with an extra 1/2 " or even a 1/4" of plastic (a skirt) around the perimeter of the copper block to contribute strength.
I did
not put any
arm into snugging the bolts down and thus causing the fracture. It was there.
What I am concerned with now are potential leaks due to failure of the plastic top. It wouldn't take much for the crack to blossom out in the other direction. Maybe I am just paranoid, or being too critical but who needs a leak at the water block?
I think an overhang on the plastic top would provide a margin of insurance that most of us would appreciate. As, it might look a little funny (if this was taken to heart and implemented), a bevel could be cut around the plastic top for visual enhancement. Look at the snap and notice the distance from the screw to the edge of the material.
Jim
