Choosing the right drill for wood screws, the size matters for good fit. For firmly set the threads, you use the most small available drill in soft wood. If the screws break, try enlarge the pilot hole.
Even change of 1/64 inch can help a lot. For holes, the size must be same or a bit bigger than the main diameter with threads. You can guess that by means of a tool either simply looking at it.
Choose the Right Drill Bit for Wood Screws
The right size for a drill match the thickness of the screw, without threads. Here everything, what keeps the wood. Good rule: choose drill that matches the key size of the pole minus the threads.
Hold also the bit against the screw: when the edges of the center show little, it seems usually. Other way is compare with the inner diameter, so the center without threads. You can even keep screw and drill together to light, for check the minor size.
Different woods require separate changes. For hardwoods as maple, walnut or oak, always use one size bigger to stop splits. 5 mm wood screw maybe requires 4 mm pilot drill in hardwood.
In practice, for hardwoods you take a bit bigger bit, while for softwoods as cedar, pine or fir a bit less big. Softwoods keep well with standard pilot size. If screws must be very loose, choose bigger drill.
Many ways help to find sizes. Commonly #80 until #1. For instance, number 8 screw uses 8/64 inch drill, #9 the 9/64 pecan and #10 the 10/64 inch.
Fractions from 64th parts, of 1/64 until 63/64, call according to simplest match, as 1/32 inch or 1/16 inch. More small screws answer for precise tasks, that home projects rarely require. It always more easily remove wood than replace it.
