Pilot holes are a good idea in most cases, especially if the ultimate drill size is vary big. Large drills alone may not track due to cutting torque.? Accurately positioned drill points matter a lot as well. It is also a good idea to use a center drill to start a hole that need some accuracy as they tend to be much more accurate for centering the hole and much more rigid compared to most drills people use.?
Your point is good since not everyone knows this that I have run across. You are commenting on a forum that has new people just starting out with metal working and need to pick up any good info we can provide.
My dad was a machinist for 40 years or so, and also a hobby woodworker. I was lucky to be able to learn interesting things about both areas as I was growing up. Now many seem obvious to me, however there is always something to learn just around the corner no matter how much you think you know.
