How do I use a nail gun safely?

Sequential versus contact firing, setting the depth, and the double-fire that causes most injuries.

Difficulty: intermediate
Time: 35 min
Read: 3 min
Safety: warning

Short answer

Use sequential firing mode, which requires the tip to be pressed before the trigger each time. Set the depth on scrap first, keep both hands behind the tool, and always know what is on the other side of the material.

A nail gun fires a fastener at a speed that will pass through timber and keep going. Almost all injuries come from contact firing and from bouncing.

Safety

Nail guns cause serious injuries every year, including through-hand and through-limb wounds. Never disable the safety contact tip, never carry the tool with a finger on the trigger, and never point it at anyone even when apparently empty. Disconnect the air or remove the battery and the magazine before clearing a jam or adjusting anything. Nails can travel through thin material and out the other side — always know what is behind.

Step by step

Use sequential firing.The tip must be pressed against the work before the trigger will fire, one nail per trigger pull. Contact mode fires whenever the tip touches something with the trigger held, which is how double-fires and injuries happen.
Never disable the safety tip.It is the only thing preventing the tool firing into open air. Taping or removing it is how the most serious nail gun injuries occur.
Set the depth on scrap first.Nails should sit flush or fractionally below. Too proud and you have to punch them; too deep and the head pulls through thin material.
Match the nail to the job.Brad nails for trim and light fixing, finish nails for skirting and architrave, framing nails for structural timber. The gun type determines what it takes.
Know what is behind.Nails pass through thin material and can travel further than expected. Never fire toward a wall you have not checked, or where someone could be on the other side.
Keep your free hand well clear.At least 300mm from the firing point. Nails deflect off knots and follow the grain, sometimes emerging at right angles to where you aimed.
Fire square to the surface.Angled firing makes the nail deflect and skid out of the side of the timber.
Avoid firing near edges and ends.The nail follows the grain and blows out of the side. Keep back from the end of a board, or pre-drill.
Disconnect before clearing a jam.Air off and hose disconnected, or battery and magazine out. Clearing a jam on a connected tool is a standard way to get injured.
Do not bounce it along a run.Bump firing is fast and it is what causes double-fires and unintended nails. For domestic work there is no reason to use it.

Tips

Sequential mode, always. Contact firing is where the injuries come from.
Test the depth setting on scrap of the same material every time you start.
Keep your free hand at least 300mm from the nose. Nails deflect along the grain.

Common mistakes

Disabling or taping the safety contact tip — It removes the only mechanism stopping the tool firing into open air, and it is the cause of the most severe nail gun injuries.
Firing close to the end of a board — The nail follows the grain and exits the side of the timber, often into whatever — or whoever — is holding it.

If it doesn't work

Nails sitting proud

Cause: Depth set too shallow, or low air pressure — Fix: Adjust the depth control and check the compressor pressure against the tool's rating.

Nails driven too deep

Cause: Depth too aggressive — Fix: Back the depth adjuster off and retest on scrap.

Nails blowing out the side

Cause: Fired at an angle, or too near an edge — Fix: Hold the tool square and keep back from ends and edges.

Frequent jams

Cause: Wrong or damaged nails, or a dirty magazine — Fix: Use the nails specified for the tool and clean the magazine. Disconnect power before clearing.

Tool firing twice

Cause: Contact mode with recoil bounce — Fix: Switch to sequential mode.

Questions people ask

What is the difference between sequential and contact firing?

Sequential requires the tip pressed then the trigger, one nail at a time. Contact fires whenever the tip touches with the trigger held. Sequential is substantially safer and is the right default.

Do I need a compressor?

Not necessarily. Cordless and gas nailers exist and suit occasional work well. Pneumatic tools are lighter and cheaper but need a compressor and hose.

Can nails go through timber and out the other side?

Yes, particularly in thin material or when the nail deflects off a knot. Always know what is on the other side before firing.