I saw using a cemented carbide drill, but even if I finished with an end mill, the way Bali came out was terrible and I could not be removed. Therefore, I returned to this product. Processing sound is also small, so it seems to be suitable for processing aluminum panel. If it is stiff (super hard) it tends to think that it will last long, but it was wrong. I normally finish with an end mill, so it is finished in a pincad and I do not need worry about deburring.