What Drill Bit

Wood screws & fasteners

Wood screws, pocket-hole screws, and lag screws, each with its sizing tool, its chart, and a page for every size. Pick the one you're driving.

Wood screwsPilot holes by gauge (#2–#14): the finder, the full chart, and a page for every size. Pocket screwsScrew length and thread by material thickness. Lag screwsPilot holes by diameter and wood type, plus the shank clearance hole.

Working out screw length?

Lumber sizes → actual board thicknessA “2x4” is really 1½" × 3½". Screw length works off that finished thickness, not the nominal name.

Elsewhere on What Drill Bit

Wall & MasonryMetalSizes & ChartsGuides

These are general guidance sizes cross-referenced from common woodworking sources. For structural, load-bearing, or manufacturer-specific work, follow the fastener manufacturer’s or an engineer’s specifications.