A cat's paw or cat's claw is a standard carpenter's tool, consisting of a round or hexagonal bar that curves at one end to form a pointed, cup-shaped tip with a V-shaped cleft for gripping nailheads. Popular retail outlets currently call these a claw bar if it has a claw on each end, or a moulding bar if it has a claw on one end and a flatpry bar on the other. It essentially works as a small crowbar. To use the tool the user holds the tool's shank with one hand and drives the claw around a nailhead with a hammer. When the V is firmly seated around the nail's shank, the users pull the bar back to raise the head, then finishes pulling the nail with the hammer's claw. The cat's paw is well designed for demolition work, but because it tears up the wood around the nailhead, it should not be used for finish work.
History
Over one hundredyears ago, nails were individually hand-made by blacksmiths, and were therefore far more valuable than the wood they were driven into. The book Nail Pullers with Patent Reference by Raymond P. Fredrich says that in the mid-19th century, wood was viewed as so plentiful in North America that if it became necessary to change one's location, "you might even burn your house down and pick upthe nails in the ashes". Back then, nail pullers were designed to preserve the condition of the nail for reuse, and thus the design of most nail pullers ended up being what is known as the slide hammer type, which is still used today. Old lumber has now become much more valuable than the nails that might hold it in place, so there has been a move toward designs that take out nails with less damage to the old growth wood. The cat's paw is still in use, but due to its design, which features an open "V" shape out at the end of a pry bar, the opening is widest right at the point where it is driven into the wood, and it causes a fair amount of damage to the wood fibers.
Alternative tools
New designs have been introduced, including the Nail Jack and Nail Hunter nail pullers, which take a pliers-like approach to the old cat's paw design. These tools contain their own built in fulcrum, but can also be struck with a hammer to drive the tips of the tool into the wood with very little damage, allowing them to dig out nails that have been driven into wood at or below the surface. The Nail Hunter nail pulling design has very precise tips that actually come completely together at the ends, for removing finish nails. The pneumatic-powered Nail Kicker allows large numbers of old nails to be efficiently pulled.
