Let me start by saying I have a lot of experience with fabrication, milling, machining and other useful things around the house. They are excellent for quickly drilling holes in most materials. They come out of the box very sharp. I think if you drill aluminum they will be perfect, although they can be aggressive enough to make you grab. Never use them to cut brass or they will grab and damage your work piece, which can lead to injury. I bought them for drilling in steel and initially they worked very well. The problem with these bits when you use them on steel is that they are so aggressive that they wear out very quickly; maybe even break or chip if you're not careful. The 1/2" drill bit broke one of the grooves on the third or fourth hole I drilled. If I had used machining lube and a drill this might not have happened (I used a battery powered hand drill) but these aren't machining bits are wholesaler bits which need to be strong enough to do the job anyway. I love these bits when used properly, but don't expect them to last a lifetime, especially as one day the edge will chip, these bits are sharpened with a "pilot's point" so if you sharpen them , you no longer have the bit you started with.