Anyone who has handled a large woodworking project with a traditional hammer and nails appreciates the value and convenience of automatic nailers, known to most construction workers as nail guns. Framing carpenters, roofers, and anyone else who spends most of the day driving nails know a nail gun is faster, more accurate, allows them to be more productive, and means less soreness at the end of the day.
But with that convenience comes the potential for problems. Nail gun operation results in tens of thousands of emergency room visits annually, with some of those injuries leaving permanent damage and disfigurement, and in rare cases, even deaths.
The good news is that most nail gun injuries are preventable when workers choose the right nail guns, maintain them properly, and operate them thoughtfully and carefully.
How nail guns work
No matter who makes a nail gun or how it looks, the two primary operating features are the finger trigger and a contact safety tip. The operation of nail guns depends on how the controls are used. Some triggers can be depressed to provide a continuous flow of nails while others have to be released and squeezed for each nail. On some models, users are able to switch between different modes. Some tool manufacturers have coined clever names for these modes, so it’s important workers understand how each gun actually works.
Generally speaking, what are known as “full sequential” triggers (sometimes called single-shot or restrictive triggers) offer the greatest safety. This type of nail gun requires the user to follow a series of steps to fire a nail. Typically, the worker must push the contact tip into the nailing location and then squeeze the trigger to fire the nail. The worker must release pressure on both the contact tip and the trigger before beginning the sequence for the next nail.
A “single sequential” trigger also requires following a specific order. Once again, the contact tip must be pressed in place before the trigger is squeezed. But with this type of trigger, the user doesn’t have to take pressure off the contact tip before firing the next nail.
Common nail gun problems
Nail gun-related injuries usually result from one of several situations. We’ll describe each of them here.
Double firing. A second, unintended nail firing can happen with nailers that have contact triggers, especially when the worker is trying to nail from awkward position or is overcompensating for recoil. Before the worker can release the trigger, the gun fires a second time. Since the second firing is unexpected, the gun may not be positioned correctly.
Accidental bump. If the worker is squeezing the trigger and bumps the contact tip against an object or person, the gun may fire. This can happen when another worker brushes by if the bump is strong enough to depress the contact tip. The best way to avoid this situation is to always release the trigger when not nailing.
Accidental penetration. Sometimes, a fired nail will shoot right through the piece of wood or other material and fly out from the other side. The worker may not realize there is a weak spot or a knot inside a piece of lumber until the nail flies through. That’s particularly dangerous if the worker is holding the lumber with the other hand.
Ricochets. Occasionally, a fired nail will encounter a hard surface such as a knot, or a piece of embedded metal, causing it to change direction or even bounce off the surface. At that point, the nail becomes a projectile that make strike the worker or another worker, or damage nearby surfaces.
Misses. If the nail gun isn’t in full contact with the lumber or other surface, or if it’s being used close to the edge of a workpiece, the nail may again become a projectile.
Awkward positions. Workers often find themselves in tight spaces or situations in which they have to twist and turn to access the area to be nailed, and they may forget to make sure the contact tip is fully pressed against the surface. This can also happen when toe-nailing or reaching up to place a nail. Here again, the nail can become a projectile.
Disabling safety features. Some workers may become frustrated with safety features and seek ways to bypass or disable them. That can increase the possibility of issues such as unintended firings.
Safer nail gun use
There are steps workers can take to minimize the potential for problems and injuries related to nail guns. Using only guns with full sequential triggers significantly reduces the potential for double fires and other unintentional discharges. In addition, workers should never disable or bypass safety features on nail guns.
Contractors should set rules for proper nail gun use. For example, workers should not keep their fingers on triggers when carrying nail guns or waiting to drive the next nail. They shouldn’t drag nail guns around by the hose or lower them to fellow workers who are below them.
As with so many aspects of construction safety, training is very important. Before using nail guns on a jobsite, workers should be trained in proper operation and issues that can cause problems. They should also wear safety shoes, hardhats, eye and ear protection, and other personal protective equipment (PPE) while they’re on the worksite.
Finally, encourage workers to report injuries and near misses. Near misses provide an opportunity to remind workers on the site about the potential for injury and may even uncover risks nobody had noticed, so supervisors can mitigate the hazards.