I recently purchased a countersink bit for my industrial drill and was pleased with the results... As a result of my tests I determined that this cutting tool is perfect for achieving a professional-grade finish on countersunk holes. The Fuller C9M number complete countersink has a sharp point that allows for clean cuts on a variety of materials. One downside to this tool is that it may wear down more quickly than other brands on the market. Overall, I highly recommend this product to others in the industrial and scientific industry..