Here is our third excerpt from Charles Platt’s high-recommended Make: Tools book. The first excerpt covered how to use a miter box and the second looked at handsaw basics. You can read my full review of Make: Tools on Boing Boing. -Gareth Branwyn
Hammer Weights and Types
The weight rating of a hammer is the weight of its head only. An average finishing hammer has a 16-ounce head and a 16-inch handle. Smaller, lighter hammers are appropriate for smaller nails that don’t require so much driving force, and for smaller people who may have less physical strength. A heavier hammer requires more strength, but its greater momentum can sink larger nails more quickly—if you can control it.
At least a dozen different styles of hammers exist, the claw hammer being the most popular variety. The nail-pulling action of the claw provides a lot of leverage, but this force is transmitted downward by the head of the hammer, and can damage the wood that you’re working on. To prevent this damage, insert a small piece of plywood or other thin scrap material. See Figure 1.
All hammers used to have wooden handles, and some traditionalists still prefer their look and feel. However, the wood tends to loosen in the head of the hammer, and I see no reason to use this type of hammer anymore. A fiberglass handle is lighter and stronger. You can also buy a hammer with a steel handle, which is the strongest type, but it adds weight where you don’t really want it. Weight concentrated in the head of the hammer is more useful, because that’s the part that hits the nail.
A hammer with a cross peen is useful for starting a small nail or tack. The peen is the tapering section where a claw would normally be. See Figure 2. When you turn the hammer upside-down, the peen is narrow enough to tap the head of the nail, striking it between your finger and thumb. Once the nail has sunk a little way into the wood, you can remove your hand, rotate the hammer, and finish the job.
In a cross peen hammer, the peen is at right angles to the handle—that is, across it. In a straight peen hammer, the peen is parallel with the handle; but this type is seldom seen.
A sledge hammer can have a head weighing 3lbs or more, and can be used to drive stakes into the ground. It can also break up concrete, masonry, or just about anything else. A small sledge is shown in Figure 3.
A rubber mallet is useful for aligning delicate objects or nudging them into position, where the steel head of a hammer would cause damage. See Figure 4.
Various alternatives exist for inserting or removing fasteners. Here are just a few.
A brad pusher has a rounded handle attached to a thin magnetic plunger inside a hollow tube. If you are using small, thin brads, you can load one into the tube, where the magnetic plunger will retain it. You force the brad it into wood by pushing the handle. This only works with soft woods. See Figure 5.
While electric versions of staple guns are available, the old hand-powered tool will work for you if you have a strong grip. This is much quicker than hammering small nails. If you look underneath an upholstered chair, you’re likely to find that the fabric has been secured with staples. See Figure 6.
A special-purpose staple gun is available for round-topped staples that are ideal for securing low-voltage wires such as telephone or Ethernet cables.
Rivets are a quick way to fasten two pieces of thin material together. You drill a hole in each material, push a rivet through both holes, engage its tail in the riveter, and squeeze the handles. The underside of the rivet swells up, and then the tail snaps off.
Rivets are made of soft metal such as aluminum, and tend to be weaker than comparably sized screws or bolts. You have to use exactly the right length of rivet, to match the thickness of the materials that you are fastening. This is a quick procedure, and you don’t need access to the underside of the materials. A riveter is shown in Figure 7.
A nail gun is loaded with special nails mounted in strips. Often powered by compressed air, the nail gun shoots a nail fully into a piece of wood when you press the trigger.
Heavy-duty powered tools of the kind used on construction sites are mostly outside the scope of this book.
A pry bar is designed for removing nails. See Figure 8. The curved end functions like the head of a claw hammer, but spreads the force more widely, so it is less likely to dent or damage the wood. The other end of the pry bar can be inserted in a crack between two boards, or between a door and its frame, if you need to pry the pieces apart. The hole in this end of the pry bar allows it to be used on nails with flat heads that are sticking out. Pry bars are available in many sizes.
Types of Nails
Figure 9, from left to right, shows a brad, a roofing nail, a sinker, a ring-shank nail, a large finishing nail, a common nail, a drywall nail, and a tack.
A brad is always thin and short, often used for attaching very small pieces of trim. It may be installed with a brad pusher, as shown in Figure 5.
Roofing nails have wider heads to spread the pressure across a greater area, so that the head is less likely to penetrate asphalt sheeting. They may be galvanized, or may be made of stainless steel, to resist corrosion.
A sinker is coated with a thin film of adhesive that melts from friction when the nail is driven into wood. The adhesive cools almost immediately and then sticks to the wood, preventing the nail from coming loose. This type of nail is easily identified by the gold sheen of the adhesive. The head is embossed, to engage with a similar pattern in the striking face of a framing hammer.
Ring shank nails have ridges around the shaft (which is also known as the shank). The ridges help to hold the nail in place.
Finishing nails have small, rounded heads, the idea being that you can embed the head in the wood, recessing it so that it can be concealed with some caulking or wood filler, after which it can be painted over. To push the nail in below the surface of the wood, you can hammer it with a device designed for this purpose. A nail set has a flat or concave tip, while a center punch has a pointed tip, like an awl but heavier. In Figure 10, nail sets are shown at left and right, while an automatic center punch is shown at center. A nail sets must be hit with a hammer, while the automatic center punch triggers an internal spring-loaded mechanism when you push down on it hard. The center punch is appropriate for finishing nails, which have a small dimple in the head.
Drywall nails have a contoured head that is intended to recess itself in sheets of drywall that are being attached to wooden two-by-fours during the construction of a house.
Tacks taper to a very sharp point, and can be pushed into place with your thumb before being hit with a tack hammer. They are intended to secure fabric.
If you wander around a big-box hardware store, you should find all of these and probably some other variants, too. Nails are usually not appropriate for small projects such as the ones in this book, but are still widely used in construction work and furniture upholstery.
In Europe, nails sizes are measured in millimeters, but in the United States, a very ancient system is used. A so-called “two penny” nail is 1” in length, while a “three penny” nail is 1¼” in length—and so on, in increments of ¼”, up to a ten penny nail, which is 3”. After that the system becomes erratic, as shown in Figure 11.
In England, before the money was decimalized, there used to be 240 pennies in a pound sterling, and a penny used to be represented with letter d. Why a d? Because it was an abbreviation for denarius, a Latin word that was used when the Romans occupied England a couple of thousand years ago. When you buy a box of 1¼” three-penny nails with “3d” on the label, this is a piece of history from the very distant past. Look carefully, and you’ll see the “3d” in Figure 11.
Nails are sold by weight—typically in boxes weighing 1lb, 5lbs, or (in some cases) 30lbs and even 50lbs. As the nails get longer, they also get fatter. But how many nails are in a pound? That depends. Figure 12 shows approximate quantities for common nails and finishing nails.
How a Nail Works
In a word: friction. When a hammer forces the nail into wood, the nail squeezes the wood, and the wood pushes back. This pressure prevents the nail from falling out. If the wood has not completed its drying process, it may shrink as it continues to dry, in which case the friction will diminish, and the nail may become less secure.
Screws create a much better connection with the wood, but they are more expensive, and driving a screw takes more time than hammering a nail. On a construction site, time is valuable, which is why nails still tend to be used.