A.Scott Smith, vice president of nail manufacturer Prime Source Building Products, responds: A box nail has a smaller gauge shank than a common nail. For example, while a 10d (3-inch long) common nail has a 9-gauge (0.148-inch diameter) shank, a 10d box nail has a 10 1/2-gauge (0.125-inch diameter) shank, which is thinner. Because a box nail is lighter than a common nail, it has less shear strength.

Cooler and sinker nails also have a smaller gauge shank than a common nail, but not as small as the shank of a box nail. 10d sinkers and 10d coolers are both a little shorter (2 7/8 inches), and have an 11-gauge (0.120-inch diameter) shank. Sinker and cooler nails are usually resin-coated; the resin acts as a lubricant as the nail is driven and as an adhesive when the nail cools after being driven.

Cooler nails, like common and box nails, have a flat head. Sinker nails, on the other hand, have a bugle-shaped head to promote countersinking.

All of these terms — common, box, sinker, and cooler — refer to loose nails, not collated nails. Collated nails are categorized according to head type (full round head or clipped head), length (in inches), and shank diameter (in inches). For example, a 16d common nail (loose) is equivalent to a full round head 3 1/2-inch-long 0.162-inch-diameter collated nail.