Quote Originally Posted by Istasi
I was under the impression that the process used during the WB milling process is far more precise than any lapping? Please correct me if I'm wrong.
According to Swiftech, their blocks are lapped to within +/- 0.0003" across the contact surface... so, basically, they're flatter than anything you'd ever get from a hand-done lapping job. As far as finish (smoothness) goes, anything beyond 600-grit or so is mainly for aesthetics--it's the flatness that really matters.