I purchased two of this time. Working with SKD 11 material drilling machine We used a reamer at removal rate of 0.1, 1st crushing with eyes with 16 holes in hole, 25 pieces of second eye broke with eye heat. It is regrettable only for things that are not expensive but expensive, although it is impossible to send. If it is a product of another company, you can do reamer work without difficulty if it is about HRC55. I will not purchase it again.