16d

16d is a common size designation for nails used in North American carpentry. The “d” stands for penny, a historical currency unit; in nail sizing, higher numbers indicate longer nails. The system originated in Britain and was adopted in the United States, with the number historically reflecting the price, in pence, for a hundred nails.

A 16d nail is typically 3.5 inches long, making it one of the longer common nails used for framing and structural connections. The diameter varies with the nail type, but a typical 16d common nail measures roughly around 0.162 inches in diameter. Nails may have smooth, ring-shanked, or other engineered shanks, with ring- or screw-like designs providing greater withdrawal resistance in some applications.

Materials and coatings also vary. Common 16d nails are made of mild steel and are available in bright (uncoated) form for interior use. For exterior or damp locations, hot-dip galvanized or coated variants are common to improve corrosion resistance, and stainless steel nails are used in high-moisture or specialty environments.

Applications and context. The 16d nail is widely used for framing walls, floors, and other structural wood connections, where a strong, long fastening is required. It is often selected when nails must penetrate thick lumber or when several minutes of driving and high shear strength are needed. Related sizes in the same family include 8d, 10d, and 12d, which indicate progressively shorter nails.