When nailing up moldings and other thin workpieces, boring a pilot hole first helps prevent the nails from splitting the wood, especially when nailing near the board's end. What if you don't have the right size drill bit? Simply chuck a finishing nail in the drill to bore perfect-size pilot holes. Apply light pressure on the drill to prevent the nail from bending.
Drilling Pilot Holes
This extra step will prevent wood splitting if you do it before nailing
By Roy Barnhart