I've been doing CNC work with the same settings I've done dozens of times before with the same CED, CEL, OL bits from another company and couldn't. I can't figure out why the beats broke. At first I thought the work had changed or something was wrong with the material, and then I finally realized it was the poor quality of the bits. I ordered these from Revain because it was easier, but ended up not saving any money because I had to re-buy them from another company.