Flooring Nails: Product Guide

Length

The length of a nail is the total distance from the top of the head to the tip of the point. In general, the longer the nail, the stronger the hold. However, because the point provides so much of the holding power, it is important to choose a nail slightly shorter than the combined depth of the material being installed and the substrate. As can be seen below, a nail driven so that the point is through the substrate loses 20% of it's strength.

The penny system for sizing nails began in England in the Middle Ages. It referred to the price of 100 nails of any given size. 100 four penny nails cost our pennies; 100 ten penny nails cost ten pennies and so on. The letter "d" (the English symbol for pence) was used to abbreviate "penny". Today, the penny system refers to the length of the nails one inch and longer. A one inch nail is two penny (2d) nail. Sizes increase 1/4 inch for each penny increase. A 3d nail is therefore, 1 1/4 inch long; a 4d rail is 1 1/2 inch long and so forth.