Finish nails are nails that are, as their name suggests, used for a variety of applications to add finishing touches. There are several different types of nails, finishing nails, common nails, brads and casing just to, to name a few. There are also very specific nails that are designed to be used in masonry or brick, drywall and roofing. Finishing nails have a different intent as they are not meant to be seen, or at the least be inconspicuous in the finished product. They have a head that is much smaller than a common nail, with a slight indentation, as frequently the head is driven slightly below the surface of the material that they are driven into, or countersunk. The head on a finishing nail is only slightly larger than the shaft of the nail, which facilitates it being driven in to follow the shaft.
Finishing nails are made with different gauges of steel wire, and come in a verity of lengths and gauge (thickness) of nail. Common sizes that you will find finishing nails in are: 2d, 3d, 4d, 5d, 6d, 7d, 8d, 9d, 10d, 12d, 16d and 20d. A 2d nail is 1 inch long, and the sizes increase by 1/4 inch increments until it reaches 16d. At that point, the length increases in 1/2 inch increments. The gauge of nail, or the thickness of the shaft, will increase in relation to the length of the nail. Nails are sized by "pennyweight", which is a very old custom of most likely England, where 100 nails could be purchased for a certain number of pennies, hence 2d, 3d, and so on. The "d" stands for the denarius, which was the roman penny.
Applications of Finishing Nails
Finishing nails can be used in just about any application where a small, inconspicuous nail is needed. They are not, however, typically intended for heavy-duty use or for anything that is bearing a lot of weight. They are used as a fastener to tack items to another surface. This might include interior door or floorboard trim or molding, counter top trim, door framing trim, paneling, cabinetry, wainscoting, furniture and other similar small wood working projects.
Use of Finishing Nails
Possibly the most common use of finishing nails is in molding and trim around the interior of a home. Frequently, a nail set is used to countersink the nail. A nail set looks almost like an awl, a pointed piece of metal that is placed against the head of the nail and driven with a hammer to the end of it's handle. The nail is driven to where it is nearly flush with the surface of the material being secured, then a nail set is used to drive the nail slightly below the surface of the material. The indentation of the nail can then be filled with putty or filler, and sanded when dry so that the nail is not visible. In other materials, such as in some outdoor applications, the hole created by the nail head will inherently be filled with debris, making it nearly invisible.