Nails are used in a variety of construction tasks, for box making, furniture building, etc. Though not as tightly defined as machine screws and nuts which must mate with one another, nails are standardized to some degree, particularly those used for structural purposes. The following article tabulates some of the standard nail sizes and briefly describes the wide range of nails available through nail length charts.
STANDARD NAIL SIZES/NAIL MEASUREMENTS
The nail size charts below illustrate industry standards for nail sizes and their dimensions. Under “nail size,” the “penny size” (aka, pennyweight) refers to a standard nail unit. Nails are measured in pennies, believed to be from older times when nails were sold by the penny. At the time, the abbreviation for pennies was d, so nail sizes are described as 2d nails, 3d nails, etc. So a 16 penny nail is also described as a 16d nail, and 8 penny nails are abbreviated as 8 d nails. Pennyweight does not correspond exactly to nail weight, gauge, or other measurements, however; for example common 10d nails are 3" long with a 5/16" head diameter and a 9 gauge shank.
Though still in common use, the penny system is considered obsolete, and some international vendors do not use it. The shank diameter and length refer to the shaft part of the nail, called the shank, which is driven into the surface. The head is, of course, the top portion struck to drive the nail into the material.
A variety of nail types exist. Nails are designed to resist both pullout and shear, with shear strength determined mainly by the shank diameter and pullout strength affected by that and the shank's design. Nails used for framing typically have smooth shanks as they are mostly used in supporting lateral loads where pullout resistance plays only a small role. Thus, the common nail serves adequately in this setting.
Pullout resistance is increased by adding rings or threads or both to the shank. These so-called deformed-shank nails are used in other aspects of construction to ensure that the nail does not pull out due to wind buffeting or pedestrian traffic, for instance. Threaded-shank nails rotate as they are driven into wood or masonry, while ring-shank nails promote a wedging action between the nail and the wood fibers. Ring-shank nails are often used in softwoods while barbed shanks increase the holding power of nails in hardwood.
Box nails are slightly smaller than common nails and are used where holding strength is less of a concern, such as for crate making and similar non-structural applications.
Nail material varies from bright steel for indoor use to electro-galvanized or zinc-dipped coated for exterior applications. Stainless steel is used as well where nails may be visible such as for hanging natural siding. Other special materials, such as copper, are available for unusual applications. While most nails are made from wire, some nails are “cut,” such as those use for nailing into masonry surfaces.
Nail heads vary according to the application, as well. For instance, roofing nails incorporate thin, wide heads that both lay flat under succeeding shingles and provide a wide bearing surface against the material to keep it from tearing. Finishing nails have small heads that grip the wood slightly but enable the nails to be sunk below the surface and later puttied over. Flooring nails used to install subfloors also have wider, flat heads – and are usually ring shanked as well – again to lie flat beneath the finished flooring and to provide protection from boards working loose and developing squeaks.
Specialty nails abound. Double-headed, or duplex, nails are used for temporary construction, such as setting scaffolding, where one head allows for the nail to be driven fully into the wood while the second head provides a way of pulling the nail out once the job is completed. Spring-head roofing nails are used for attaching corrugated roofing. Upholstery nails have wide, domed heads to give furniture a finished look.
Some nails are coated, such as sinker nails, to increase pullout resistance. Concrete coatings applied to nail shanks are intended to roughen up the shank surface for a better bite on wood. Vinyl coatings on nails are intended to melt upon driving and then re-harden to improve the nail shank adhesion to the wood.
Wood screws have taken some of the market share away from nails owing to the development of powered drivers. Deck construction is one such example where threaded fasteners dominate as the screw provides excellent holding power against wind-borne uplift. For structural framing work, nails continue to be the preferred fastening method because of their superior shear strength.
This article presented a brief discussion of nail dimensions and standard nail sizes. For more information on related products or processes, consult our other guides or visit the Thomas Supplier Discovery Platform to locate potential sources of supply or view details on specific products. For a detailed technical discussion of nail pullout resistance, refer to this article by the USDA’s Forest Products Laboratory.