Have been using these bits for about 3 years now. However, this could be my last order. We are a full time shop cutting 8 hours a day, these bits used to treat me pretty well but now they seem to break more often. Not only do they break on my rough gears, but even on my final gears. I just had a brand new crack only 0.01" apart and 0.06" deep. I've ordered 5 more of these and 5 from another company to see if these bits really give me any trouble.