Nail guns are very useful tools for joining wood and other materials quickly and efficiently. They have made hand nailing virtually obsolete for professional builders and now do-it-yourselfers as well.

The biggest advantage of nail guns is their ability to quickly and repeatedly fire a fastener into the substrate. In high-velocity applications, such as framing and roofing nails, nail guns are typically set to fire a nail each time the muzzle contacts the surface, as long as the trigger is pulled. They can fire rapidly almost like an automatic weapon.

Last week, while doing a minor woodworking project in my barn, I was reminded of how quickly a large framing nail gun can deliver three-inch framing nails.

As he nailed some bridges between the floor joists, he held the bridge wood in one hand and the nail gun in the other. As he built an overhead storage space to get some of the clutter off the floor, he was standing on some of the clutter that would soon be stored. Not exactly a steady jog.

When using a contact fire nail gun, like most framing nail guns, you need to have just the right touch to prevent recoil from the gun causing it to fire a second nail right on top of the first. Normally this is easy as you just swing the gun around and let it bounce off the work while the nail is fired.

However, if you’re trying to drive a nail right where you want it, you can also compress the muzzle and then pull the trigger to fire the nail. This works well when you develop the correct touch to allow the gun to back up into the work piece. Experienced carpenters do it all the time.

However, if you lose your balance just as you pull the trigger, I’ve found that it’s possible to fire not just two, but three nails into the same hole. Only the first manages to enter; the other two shoot off in random directions.

Luckily, this time, most of the time I missed the parts of my body that were in line with the nail path and got by with just a minor scratch on my thumb. It swelled up nicely and still hurts a bit today.

So here are some nail gun safety tips to add to the list in your owner’s manual:

1. Understand the difference between sequential trip trigger and contact trip trigger. Make sure you’re using the right one for the right job. The Bostich catalog has a good description of how each trigger works and when they should be used.

2. When attempting to accurately position a fastener with a contact fire nail gun, be sure of your target and background as you would if you were shooting a gun. There is always the possibility of a double shot that will not be contained by the wood. Keep body parts out of possible line of fire.

3. When using a pneumatic nail gun, be alert to the added hazard of the air hose. Compressed air has its own dangers, but having an air hose stretched across a construction site adds to the already dangerous environment. Seeing roofers with pneumatic nail guns always reminds me of Mark Twain’s story in the city: he said that one day he saw a guy on a ledge threatening to jump off. A large crowd had gathered below, but Mark Twain said that he was the only one in the group with the presence of mind to throw him a rope and pull him down. The air hose always looks like someone has already thrown a rope at the roofers.

4. When clamping down on a workpiece for nailing, keep in mind that the force of the nail gun will go through any obstacles in the wood, such as knots or other fasteners. However, the path through the forest is not always safe. Nails have been known to come out of the side of the wood and in some cases even make a U-turn and go back into the gun. Keep your hand at least the length of the fastener you are shooting away from the muzzle at all times when joining wood.

5. Do not use rusty fasteners. Using old nails in a nail gun can not only damage the gun, it can also send rust and scale back at the operator. Be sure to use new, clean nails for safe operation.

6. Wear your safety glasses or face shield. Not only can the nail gun send errant nails toward you, but the force of the nailing operation can also splinter the substrate. And if you ignored number six above, rust and scale can also be kicked out. So protect your eyes. It’s much easier to use a nail gun safely when you can cut what you’re working with.

7. Maintain the nail gun properly. Regular maintenance and lubrication will reduce the chance of sticking and misfires requiring repairs and potentially dangerous breakout procedures.

8. Read and follow all manufacturer’s safety rules and procedures. Chances are they’ve already been sued for something there.