Nail gun

"Air hammer" redirects here. For the Transformers character, see Air Hammer.

File:Using a nail gun.jpg

Pneumatic nail gun in use

A nail gun, nailgun or nailer is a type of tool used to drive nails into wood or some other kind of material. It is usually driven by electromagnetism, compressed air (pneumatic), highly flammable gases such as butane or propane, or, for powder-actuated tools, a small explosive charge. Nail guns have in many ways replaced hammers as tools of choice among builders.

Usage

Nail guns do not use individual fasteners. Instead, the fasteners are mounted in long strips (similar to a stick of staples) or collated in a paper or plastic carrier, depending on the design of the nailgun. Some full head nail guns, especially those used for pallet making and roofing, use long plastic or wire collated coils. Some strip nailers use a clipped head so the nails can be placed closer together, which necessitates less frequent reloading. Industrial nailers designed for use against steel or concrete may have a self-loading action for the explosive caps, but most require nails to be loaded by hand. Nail guns vary in the length and gauge (thickness) of nails they can drive.

File:AirCompressorHusky.JPG

Air compressor supplies air into a nail gun

The smallest size of fasteners are normally 24 to 22 gauge (0.60 to 0.71 mm diameter) and generally have no head. They are used for attaching beadings, mouldings and so forth to furniture, etc. Lengths are normally in the range ⅜ to 1¼ in. (10 to 32 mm) although some specialist manufacturers supply up to 2 in. (50 mm)

The next size up is the 18 gauge (1.22 mm diameter) fixing, often referred to as a "brad nail". These fastenings are also used to fix mouldings but can be used to used in the same way as the smaller 22 to 24 gauge fastenings. Their greater strength leads to their use in trim carpentry on hardwoods where some hole filling is acceptable. Whilst most 18 gauge brads have heads, some manufacturers do offer headless fastenings. Lengths range from ⅝ in to 2 in. (16 mm to 50 mm)

Going up from 18 gauge fastenings the next sizes are 16 and 15 gauge (1.63 and 1.83 mm diameter). These are generally referred to a "finish nails". They come in lengths between ⅝ and 2½ in. (16 to 64 mm) and are used in the general fixing of much softwood and MDF trim work (such as baseboard/skirtings, architraves, etc) where the holes will be filled and the work painted afterwards.

The largest sizes of conventional collated fastenings are the clipped head and full head nails which are used in framing, fencing and other forms of structural and exterior work. These nails generally have a shank diameter of 0.11 to 0.13 in. (2.9 to 3.1 mm) although some manufacturers offer smaller diameter nails as well. General lengths are in the range 2 in to ​3 ¹⁄₃ in (50 to 90 mm). Shank styles include plain, ring annular, twisted, etc and a variety of materials and finishes are offered including plain steel, galvanised steel, sherardised steel, stainless steel, etc depending on the pull-out resistance, corrosion resistance, etc required for the given application. These sizes of fastenings are available in stick collated form (often 20° to 21° for full head, 28° to 34° for clipped head) or coil form (for use in pallet/roofing nailers) depending on the application. Full-head nails have greater pull-out resistance than clipped head nails and are mandated by code in many hurricane zones for structural framing.

Another type of fastening commonly found in construction is the strap fastening which is roughly analogous to the large head clout nail. These are used in conjunction with a strap shot nailer (or positive placement nailer UK) to fix metalwork such as joist hangers, corner plates, strengthening straps, etc to timber structures. They differ from conventional nailers in that the point of the fastening is not sheathed so it can be exactly positioned before firing the nail gun.

Other specialist nailers are also available which can drive spikes up to 6¼ inches long, fix wood to steel, etc.

A variation on the nail gun is the palm nailer which is a lightweight handheld pneumatic nailer that straps to the hand. It is convenient for working in tight spaces where a conventional nailer won't fit and is flexible enough to drive either short nails into metal straps or six inch nails into timber. By repeated hammer action (of around 40 hits per second) the fastener is driven into the material by a more constant palm pressure (as opposed to a conventional nailgun which drives the nail against the inertia of the nailgun itself).

Safety

In the United States, about 37,000 people every year go to emergency rooms with injuries from nail guns, according to the U.S. Centers for Disease Control (CDC). Forty percent of those injuries occur to consumers. Nail gun injuries tripled between 1991 to 2005. Foot and hand injuries are among the most common. The U.S. Consumer Product Safety Commission estimates that treating nail gun wounds costs at least $338 million per year nationally in emergency medical care, rehabilitation, and workers' compensation.

All kinds of nail guns can be dangerous, so safety precautions similar to those for a firearm are usually recommended for their use. For example, the Safe Nailer, a concept product designed for a Boston University School of Management business plan project, has a capacitative sensor that lets the nail gun know when it is pointing at human skin. When the Safe Nailer detects human skin in its trajectory, the nail gun locks its firing mechanism, avoiding potentially fatal injuries. For safety, nail guns are designed to be used with the muzzle touching the target. Unless specifically modified for the purpose, they are not effective projectile weapons.

The most common firing mechanism is the dual-action contact-trip trigger, which requires that the manual trigger and nose contact element both be depressed for a nail to be discharged. The sequential-trip trigger, which is safer, requires the nose contact to be depressed before the manual trigger, rather than simultaneously with the trigger. Approximately 65% to 69% of injuries from contact-trip tools could be prevented through the use of a sequential-trip trigger, according to the CDC. When using a nail gun it is important to note that the safety features above are there for a reason. Actions such as leaving the trigger depressed while just using the tip as the triggering device can lead to serious injury.

Powder actuation

Explosive-powered ("powder actuated") nailguns fall into two broad categories:

• Direct drive or high velocity devices. This uses gas pressure acting directly on the nail to drive it.
• Indirect drive or low velocity devices. This uses gas pressure acting on a heavy piston which drives the nail. Indirect drive nailers are safer because they cannot launch a free-flying projectile even if tampered with or misused, and the lower velocity of the nails is less likely to cause explosive shattering of the work substrate.

Either type can, with the right cartridge loads, be very powerful indeed, driving a nail or other fastener into hard concrete, stone, rolled steelwork, etc., with ease.

Gallery

• Nail gun sweden 20030918.jpg

  Pneumatic nail guns require air hoses to fire

• Nailgun open piston.jpg

  In the nailgun's head, the inner chamber contains the piston assembly which drives the nail.

• Senco nails 20050612.jpg

  Nails come in clips for use in nail guns

• Blankcartridge.jpg

  Cartridges, used in powder actuated nail guns

See also

• Staple gun
• Air Compressor
• Needlegun scaler
• Paslode impulse

External links

• Original nail gun idea started in Winsted
• "Nail Gun Injuries Treated in Emergency Departments, United States, 2001-2005"
• Accidental self-inflicted nail gun injury to the heart

da:Sømpistol sv:Spikpistol