how to drill

Hi, It has been a while since I met you. Sorry I do not know a good site on drilling, but then I have not been looking for one.

But I will try to answer when drilling a pilot hole is a good thing to do. In my opinion drilling a pilot hole is something you usually want to do in a home shop environment. Look at a drill while it is turning and back lighted. There is an area in the center where the light is always blocked. That shows that when you are drilling the center is pushing the metal from the center out to where the drill has cutting edges. So if you drill a pilot hole that is the diameter of this center section, you cut the amount of force needed to push the drill way down. So you want to drill a pilot hole that is the same size as this center section or maybe just a little bigger. Then if your machine is rigid enough and has enough horse power, you can use a drill that is the size of the hole you want. If your machine is not rigid enough or does not have enough hp. Then enlarge the hole in several steps. If you are drilling something soft like aluminium, you can probably skip the pilot hole. If you are drilling some thing like stainless that work hardens, then you want the drill to be getting below the area that work hardened. So a pilot hole will be a big help.

=20 Dan

The main thing is pressure and speed, pressure being more important in my opinion.Use as much pressure as you can without breaking the drill (this will come with experience) When I was working with apprentices most of the cases of burned and worn drill cutting edges was because of not enough pressure.