Recently I had to add an attachment to the tractor bucket that required 8 holes to be drilled. My plan was to use a bit to get the hole started and then use a step bit to finish the holes. I must say that I began the job without any cutting oil and after about 30 minutes, I only had very hot drill bits and only about a hole and a half completed. I chucked those bits and then purchased these. A week later, I tried this with cutting oil and the new bits and it did help a lot. I was more able to get the bits to bite and tap the holes. However, it was not magic. I still had to work pretty hard, after the first hole which went fairly easy. The next holes got progressively more difficult. In other words, the bit dulled fast even with a very liberal use of cutting oil. They oil still got hot enough to smoke and the bits did get red hot at some points. I tried multiple methods and speeds to get these holes done. I used a lot of oil. So, the bits worked but not as good as folks were saying they did at least not for me. I would actually rate them a 3.5 to 3.7 if able to give partial stars. Hope that helps.
Rating:
[5 of 5 Stars!]