Perfect Pilot Holes – Drill to Match Wood Screw Size

 Perfect Pilot Holes – Drill to Match Wood Screw Size

Most of the problems related to driving screws have nothing to do with the screw itself, but everything to do with the pilot hole, or in some cases, the complete lack  of pilot hole. As tempting as it might be to muscle a wood screw into a bare board, just remember that most wood screws are too large to be forced into a board without some type of path to lead the way. I know this extra step is tempting to ignore, but drilling the right size pilot hole first can mean the difference between your wood project being a success, or a project disaster.

What Pilot Hole Size Should I Drill?

As a general rule, a pilot hole should be the same diameter as the root of the screw (the center core just below the threads). This allows the bulk of a screw to enter a board without splitting the grain, yet still allow the threads to do their work of pulling two boards together to form a joint. The most common mistake people make in drilling pilot holes is to make the hole too small, believing that the more snug the wood screw, the stronger the joint.

Not so, necessarily. Keep in mind that the real job of a wood screw is to pull boards together just long enough to complete whatever joinery technique you’re using for that project. If we’re talking about a glued joint, that means the primary job of a wood screw is to act like a clamp, bringing two boards together just long enough to make the surfaces bond to each other and the glue to dry. For joints without glue, the job of a wood screw is to align the project pieces in their rightful place, allowing the joint to work in tandem with other joints to support the overall structure. Interestingly enough, the wood screw itself offers little value to the strength of a joint.

Countersink for the Perfect Fit

A pilot hole by itself might be fine for the threaded portion of the screw, but it doesn’t provide room for the head, which is quite a bit larger than the rest of the screw. A simple solution to this problem is to use a countersink bit, which creates both a pilot hole for the threads, and a larger hole for the head of the screw.

Straight or Tapered?

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