Making a thread for your screw, also referred to as drilling screw holes, is a practice of good woodworking. Making a thread for your screw not only makes your screw easier to push in, but it also reduces the strain your screw will put on the wood. Simply screwing through a piece of wood may cause it to splinter or snap; the wood may crack while you work the screw, or even hours afterward.
Secure the wood in which you plan to make the thread; you can use a vice, clamps on a sawhorse or your own preferred method.
Mark the spot where you plan to prepare the thread. If you intend for the thread to pass all the way through the wood, leave open space beneath the wood for the drill bit.
Select a drill bit that makes a hole slightly smaller than the screw for which you plan to drill. Attach the bit to your drill.
Press the end of the drill bit into the place you want to drill your thread. Hold the drill to the wood at the angle at which you want to make the thread -- usually 90 degrees. When ready, engage the drill and gently press down toward the wood. Continue drilling until you have achieved your desired depth.
Replace your drill bit with a countersink bit. This bit will make an indentation for the head of the screw to sit below the wood's surface, relieving extra stress on the wood.
Place your drill, with the countersink bit, over the hole you just drilled. Engage the drill, and press down just long and hard enough to make an indentation into which your desired screw head will fit.