Originally posted by: BonzaiDuck
Either lap the sucker, or buy it "custom-lapped."
Just be careful to grind away the ridge-line across the heatsink base so that "flat" doesn't mean the heatsink sits cockeyed. The SVC (Silicon Valley Compucycle) tech-rep told me they designed a jig to do it, and it took them about a day to "get it right."