I'm new to woodworking so hopefully this question falls within this exchanges guidelines, please advise if not.
There will be a block of wood in the slot in the above photo that I worry will split if I don't drill a pilot hole first. The only issue is that my drill bit is not long enough to make it all the way through. As shown below:
Why are the screws listed as size 12 but all drill bits are listed as fractions as shown here? How am I supposed to know what size is correct? And moreover, how can I tell if the length of the bits are at least 3 inches none of the packaging seems to list length, only the size as a fraction. :
To complicate matters, I want the screw to be perfectly flush so I believe I need a countersink to do that properly, I've been looking at the countersinks below I can't tell if the bits are at least 3 inches or whether the width is correct.
I am totally overwhelmed at this point - which drill bit should I be using?