These wrenches were made to assist us with building our rep-rap printer. They are a little different then many wrenches in that they grab more surface area of the nut based on the design. Therefore they get a better grip on the nut and are perfectly strong enough to adjust the print bed or hold a nut in place for mounting.
I realize this may be an egg before the chicken kind of thing. So If you don't have a 3D printer but you're interested in getting one of these sets. You can go to http://www.badbrick.com/catalog and get one if you'd like.
In MakerWare, I modify the "Medium" settings:
Quality: Layer Height = 0.12
All other defaults are the same.