What Drill Bit

Sizes & charts

Two reference charts: drill bit sizes across every system, and what a board actually measures. A 2x4's real 1½" thickness sets pocket-hole screw length, so the lumber chart feeds the screw tools.

Drill bit sizesConvert a size between fraction, number, letter and metric, find the nearest real bit, and open the full charts. Lumber sizesNominal vs. actual — what a 2x4 really measures (1½" × 3½"), for every common 1x and 2x board.

Elsewhere on What Drill Bit

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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.