Review on Ultra Precision Plastic Blocks 0.0001 by Fisseha Rodgers

I just got these to work today and the first thing I did was test them with a 0.0001 inch display. The blocks were square with a draft of less than 0.0001 inch. all edges. The 1,000 and 3,000 edges were perfect, but 1 of the 2,000 sides was 0.001 inches long, so they don't match (at least not until I override the oversized block in the spec). I've tried screwing them together and the edges vary between .002 and .004 inches depending on the direction, so again far from "corresponding". But for the price paid I'm satisfied. Rotating 1 block 0.001 inch doesn't take long, then I have a set to match. OTOH if you want a set that matches the bolt pattern, by the spec they will be undersized. So this set works well as either a control set or an adjustment set depending on how you sew it, but not both. That's the difference between them and the $90 "exact" set. Not perfect, but better than most cheap chinese junk you'll find around here, and the heavy plastic case looks good too.