For the best result drill a pilot hole for a screw in soft wood. Choose a drill bit with the same diameter of the screws shank and drill only as deep as the length of the unthreaded shank. If drilling into hardwood, drill a smaller hole below the shank hole for the threads as well. This hole should be half as deep as the threaded portion. Next use a drill bit a little smaller in the diameter than the screw’s shaft.
You can countersunk a flathead screw so that it sit flush with the surface. However, sometime the screw will be sunk a little deeper and you can cover the head with a dowel plug or with wood putty.
An electric drill’s combination bit can create counterbore, countersink, and pilot holes all in one maneuver. However, you can get the same result with a three drill bit.
- One equal to the screw’s head diameter
- One equal to the screw’s shank diameter
- One equal to the screw’s shaft diameter
Drill to hold the shaft, shank, and head of a wood screw; if necessary, counterbore with a plug or putty