Description: The Rotabroaches cut extremely smooth and you can be aggressive with your feed rate. These things remove some serious material, so expect a lot of stringy chips. Going back to my above caution, that pilot is spring loaded in order to also eject the slug that would ordinarily get jammed into the hole cutter......they come out like a bullet! I had one shoot across my garage 20' and hit the wall. They are no joke, wear your safety glasses!!! I was incredibly impressed with how fast and easy the Rotabroach made it through the chromoly. My 2 hole pattern was perfectly aligned due to how well the spring loaded pilot locates in the center punch prick. a tool to replace a twist drill bit for “drilling” larger holes is thin metal. Often when cutting, say a 3/8? hole in metal 1/8 thick, I end up with a hole that is kind of triangular. If I’m trying to insert a 3/8 rod in that hole I have to clean it up with a reamer to get it to work. I think the triangular hole is due to how the flutes of a drill bit “walk” around the hole as it is cutting. These cutters perform well with no issues, I'm a 33+ year tool n die metal fab,electrical controls and mechanical engineer, I build and wire and program machinery. I use these in machine building daily and it has made things easier for me. Love the product so I bought the smaller set as well.If you're doing holes, and have been using traditional hole saws, switch now, unless you're only doing holes in wood that don't require clean finished edges. For holes in aluminum and plastics such as acrylic and polycarbonate and other fabrication needs, these are the cat's meow. After 30 years of using traditional hole saws and drill bits, I can't say enough about these, or wishing I'd found them 3 decades ago. We now have the small and large sets.