Brad nails and finish nails are both used in carpentry, driven into the surface of wood materials using air compressor-powered nail guns. Most of the time, brad nails are often called finish nails or finishing nails because their sizes do not really differ that much from actual finishing nails. However, they are different types, a brad nail being the second-to-the-smallest nail that can be used in a nail gun. It has a gauge or thickness of 18 with a 1.22 mm diameter, while finish nails have gauge numbers 15 and 16, with corresponding diameters of 1.63 to 1.83mm, respectively. With the differences in sizes and lengths come differences in their uses or functions.
Brad nails are generally used in trim carpentry, where the carpenter works on doors, casings, or moldings; finish nails are used in finish or detail carpentry, such as on cabinets and storage wood containers. This is because most brad nails have flat heads that can be seen on the wood while finish nails have heads that are barely noticeable and can just be painted over to blend in. Finish nails usually are driven more strongly so that their heads are sunk or submerged into the wood to hide them from view.
Holding Woods Together
Brad nails are also used to fix wood in place or to hold two pieces together and may be removed carefully when the glue between the pieces dries. Finish nails, due to being “headless,” are only used as the final nails driven on detailed carpentry work.
Corner Spots and Central Areas
Many carpenters prefer to use brad nails for securing corners or near the corners of the wood. Brad nails are less likely to split the wood or damage the corners, with around a 70 to 80 percent probability, compared to finish nails which almost always damage wood corners. This is because brad nails have blunt ends, while finish nails have more pointed ends—making them easier to drive, and invariably making them split wood corners with the impact.
Other carpenters classify their use depending on the kind of projects they make because brad nails and finish nails differ in lengths and strengths. For small projects like tacking plywood together or making smaller woodwork where the heads will not be a problem, use brad nails. For bigger projects like dressers or wardrobes or even outdoor woodwork, use finish nails.
Hard Wood and Soft Wood
Some carpenters use brad nails for softer woods since they are thinner, while others use them for harder woods. This simply varies, again, based on the carpenter and the project. Brad nails, though thinner with smaller diameter than finish nails, are also generally shorter. The length of a brad nail varies from 5/8-inch to two inches while that of a finish nail ranges from 5/8-inch to 2 1/2 inches. Finish nails are used for driving into harder materials, but they can be used for soft materials just because their heads will be thoroughly embedded and unnoticeable when painted over.