I don't understand the Fuller tables on pilot holes for screws. Lets take a number 10 screw for example. It has a 3/16 shank diameter and a 1/8 root diameter. The Fuller chart recommends a 13/64 taper drill to do the pilot hole. Okay, 13/64 equals 3.25/16. That's bigger than the shank size so there's nothing for the threads to bite into at the top of the hole?! Or does the bit taper so quickly that the thread soon finds wood to bite into. But even this would leave a minute gap along the shank of the screw? Wouldn't I want no bigger than 3/16?
I guess drilling depth is very important. If one goes too deep, the screw won't have any wood to grab.