I have a small shop in Corona, California called IngeniumPRM. We got a rush job to make thrust chambers out of 6AL4V and had to bore a hole 10 inches deep inside of it. Everyone was super helpful getting me the tooling I needed, and this bar blew me away at what it could do. Zero harmonics, a mirror-like finish, even tool life was manageable. And if that isn't enough, the price is half what you would pay for a Sandvik or Kennametal variant. I 100% recommend this bar for any deep boring you need to achieve, and will definitely be going to them again for critical tooling needs.