This separates it from drilling which can only do round, cylindrical holes.
For these reasons, purely iron structures can be difficult to build and maintain.
Some modern machines have movable for both.
Lead looks a lot like silver, only darker and with a dull, washed-out finish.
Titanium drill bits are harder than cobalt, but because they are coated, they can't be sharpened.
This is a subtractive process that can be compared to sculpting.