Nail gun

How it works

In a pneumatic nailer, compressed air held in the handle and body acts on a piston when the tool fires. A driver blade attached to the piston strikes the head of the first nail in the magazine and sets it in the work. Collated nails in strips or coils feed forward into the nose after each shot. Senco’s manual for a framing nailer specifies an operating pressure of 70 to 120 psi, an air consumption of 10 standard cubic feet per minute at 60 cycles per minute, and a 70-nail magazine.

Two controls must be operated to fire. One is the trigger. The other is a workpiece contact element, or safety, at the nose, which must be pressed against the work. How the two are sequenced is the trigger system. Senco’s manual describes a sequential trigger, in which the contact must be made before the trigger is pulled; a contact (bump) trigger, in which the trigger and contact can be activated in any sequence so that a nail is driven each time the contact is pressed while the trigger is held; and a selective trigger that switches between the two.

Power can also come from other sources. The Nikolich patent of 1983 describes a fastener driver powered by gases from internal combustion of a fuel and air mixture, with a piston, a combustion chamber and a spark plug; Senco’s company history describes a later cordless pneumatic tool with a sealed onboard air cylinder.

Anatomy

Magazine: Holds collated nails in strip or coil form. On the Senco framing nailer a lockout stops the tool from firing when about five nails remain.
Workpiece contact element (safety): The nose member that must be pressed to the work before the tool can fire; Senco calls it the most important feature.
Trigger: Senco identifies trigger systems by color: gray for sequential, black for contact, red for selective actuation.
Depth-of-drive adjustment: A wheel that sets how far the nail is driven.
Adjustable exhaust deflector: Directs exhaust air; set by loosening a cap screw with the air disconnected.
Air inlet: A 3/8 inch NPT inlet on the Senco model, with a coupling that must relieve pressure from the tool when disconnected.
No-mar pad: A removable pad that converts the tool for flat surfaces and prevents damage to the work.

Variants

Framing nailer: Large nails for structural work, such as the Senco FramePro 701XP and 751XP with 70-nail magazines and a 30-degree magazine.
Finish and brad nailers: Smaller-gauge nailers for trim and cabinetry, offered by makers such as Senco as separate product lines from framing nailers.
Roofing nailer: A coil-fed tool for shingles; see the roofing-nailer entry.
Combustion (gas-cartridge) nailer: Powered by a fuel cell and a spark in a combustion chamber, described in the 1983 Nikolich patent.
Cordless pneumatic nailer: Senco describes its Fusion line, with a sealed onboard air cylinder in place of fuel cells.
Early mallet-struck and bulk-feed nailers: The Journal of Light Construction reports a 1907 hand-held bulk-feed nailer fired by a mallet and the Nu Matic bulk nailer of the early 1950s.

Specifications

Operating pressure · psi: 70–120 (Senco FramePro 701XP and 751XP)Senco’s safety program also states 70 to 120 psi, to be checked against the tool or owner’s manual.
Air consumption · scfm at 60 cycles per minute: 10 to 11 (same models)Useful for sizing the compressor.
Magazine capacity · nails: 70 (same models)Manufacturer’s specification table.
Weight · lb: 8 to 8.4 without fasteners (same models)Manufacturer’s specification table.
Maximum supply pressure · psig: Do not connect to air pressure that potentially exceeds 200 psigSenco manual; the hose must have a working pressure rating of at least 150 psig or 150% of the system’s maximum pressure, whichever is higher.

Made to

OSHA 29-CFR-1926-302
ANSI ISANTA-SNT-101
EN 792-13

Safety and care

Safety

Keep fingers off the trigger when not driving fasteners and never carry the tool with a finger on or under the trigger; Senco’s manual warns the tool will eject a fastener if the safety element is bumped.
Disconnect the tool from the air supply before adjusting it, doing maintenance, clearing a jammed fastener, or leaving the work station (Senco).
Never alter or remove the safety element, trigger or springs, and never use a tool whose safety element or trigger sticks or binds (Senco).
Do not drive fasteners close to the edge of the work or at too steep an angle, because the workpiece may split and the fastener may ricochet (Senco).
OSHA 29 CFR 1926.302(b)(3) requires pneumatically driven nailers and staplers with automatic fastener feed that operate above 100 psi at the tool to have a safety device on the muzzle that prevents the tool from ejecting fasteners unless the muzzle is in contact with the work surface.
OSHA 1926.302(b)(5) states that the manufacturer’s safe operating pressure for hoses, pipes, valves, filters and other fittings shall not be exceeded.

Care

Senco’s manual calls for 5 to 10 drops of Senco pneumatic oil in the air inlet twice daily, depending on how often the tool is used, and warns that other oils may damage O-rings and other parts.
Wipe the tool clean daily and inspect for wear. Use non-flammable cleaning solutions only if necessary and do not soak the tool (Senco).
Check daily that the safety element and trigger move freely. Senco lists excessive leaks, an inoperable or binding safety element, missing guards or labels and delayed firing as conditions that require the tool to be taken out of service.

Tips

Read the trigger color
Senco’s manual identifies a gray trigger as sequential actuation, a black trigger as contact actuation, and a red switch or lever as a selective tool that changes between the two. The manual advises checking the trigger mode before using the tool.1 2
Use sequential actuation when placement matters
The manual describes sequential actuation as the mode for precise fastener placement and for tool reset after each fastener. It recommends contact actuation only for experienced professionals in high-volume work such as pallets, sheathing and roofing.1
Set depth of drive with the air disconnected
The manual says to disconnect the air supply and then turn the depth wheel with the thumb or index finger to set the depth the fastener is driven. The troubleshooting table lists incorrect depth of drive as a cause of poor results, with adjustment of the setting as the remedy.1
Add the no-mar pad for flat work
The tool is built for toenailing at an angle. The manual says it can be converted for flat-surface applications by adding the no-mar pad, which prevents damage to the work surface.1
Do not run the magazine empty
On the model described, a lockout locks the workpiece contact element when about five nails remain in the magazine, so that the tool cannot fire until more nails are loaded. The manual also states that fasteners must not be loaded with the trigger or the contact element depressed.1
Run the lowest pressure that sets the nail
Senco’s manual says to operate at the minimum pressure required to set the fastener, which minimizes noise and wear, and that the regulator must be set at or below the manufacturer’s specified maximum.1
Let the tool recoil off the work before the next nail
The manual states that if the contact element re-contacts the work surface during recoil an unwanted fastener will be driven, and it advises allowing the tool to recoil completely off the surface after each fastener.1

History

Earliest documented

1944 (first pneumatic nailer, as reported); 1907 for a hand-held bulk-feed nailer fired by a mallet

United States (1944 pneumatic nailer for Hughes aircraft work); Robbinsdale, Minnesota (1907 hand-held nailer)

Don Carlson, a fastening-industry distributor writing in the Journal of Light Construction, reports that the first commercialized fully portable nail gun was a hand-held bulk-fed nailer developed in 1907 in Robbinsdale, Minnesota, which still required a mallet. He reports that the first pneumatic nailer is credited to Morris Pynoos, an engineer, who developed it in 1944 for Howard Hughes to assemble wooden parts of the “Spruce Goose” aircraft, and that he was unable to find photographs of it. Carlson also reports a stationary machine that fed and drove bulk nails from 1862, by the Doig Manufacturing Company.1

The nail gun is a mechanization of the hammer, and the delay in making it portable came from air. Carlson reports stationary nailing machines from 1862 for pallets and crates, a hand-held mallet-struck nailer in 1907, and a pneumatic nailer in 1944, but the practical job-site tool took longer. He writes that the industry in the mid-1950s could not get enough instantaneous “explosive” air power to drive a fastener longer than 5/8 inch without recoil using the simple trigger valves of air staplers.

The barrier was overcome by borrowing. In Carlson’s account Spotnails’ chief engineer saw an aircraft ejection-seat air system at a Chicago show in 1957 and adopted it around 1958: a large upper piston holds back the stored air until the trigger moves it aside, dumping the whole charge onto the drive piston. Carlson says this principle is still the key to driving long fasteners. He reports that portable nailers grew out of the makers of air staplers, which already knew how to collate staples into strips and coils, and that Burnison’s bulk-fed Nu Matic Nailer of 1951–52 was the first commercially successful job-site machine.

Paslode, Senco and others then turned the tool into a product line. Accounts relaying Paslode’s history say its first pneumatic tool was an upholstery tacker in 1959 and that a “Gun-Nailer” followed in 1964; the 1964 date is a company claim that has not been checked against a primary record. Senco’s history lists the world’s first pneumatic staplers in the 1940s and, in the 1960s, its first factory and its paper-taped framing nails and coil nails. The collated fastener was as much a part of the invention as the gun.

Power then moved off the hose. The Nikolich patent granted in 1983 describes a tool that burns a fuel and air mixture in a chamber over the piston, with a spark plug and a fan, and Tools in Action credits Paslode with inventing the cordless gas-powered nailer, a claim that rests on the trade site relaying company history. Senco says it later introduced Fusion technology, a cordless nailer with a sealed onboard air cylinder, in the 2010s. These tools keep the nailer’s form while dropping the compressor and hose.

Speed brought injury. The first systematic evidence is the 2006 study of 772 apprentice carpenters in which 45% had been injured by a nail gun, and in which injury rates were twice as high with contact trip triggers as with sequential triggers after adjustment. CDC’s 2007 report estimated 37,000 emergency department visits a year in 2001–2005, with consumer injuries about three times their 1991 level. Senco’s own manuals now state that sequential actuation is recommended for most applications and strongly recommended for less experienced users, and that contact actuation is for experienced professionals only.

Timeline

1862
Doig Manufacturing Company develops a stationary machine that feeds and drives bulk nails, according to Carlson; such machines were used in plants for pallets and crating.1
1907
A hand-held bulk-fed nailer is developed in Robbinsdale, Minnesota. It needs a mallet to drive the plunger and does not succeed for shingling.1
1944
Morris Pynoos is credited with the first pneumatic nailer, built for assembling wooden parts of the Hughes H-4 Hercules aircraft.1
1951–1952
Bill Burnison of Los Angeles invents the Nu Matic Nailer, called the first commercially successful portable nailing machine for job-site construction, for roof deck boards.1
1957
Spotnails develops the PEL, driving 18 gauge narrow crown staples with a two-step trigger meant to overcome recoil; Carlson calls it ultimately unsuccessful.1
about 1958
Spotnails engineer Bill Beckman sees an aircraft ejection-seat “pop-it” air system and adapts it to dump stored air onto the drive piston; Carlson says the principle is still used to drive long fasteners without recoil.1
1959
Paslode introduces a light-duty pneumatic upholstery tacker, called its first pneumatic tool in accounts relaying Paslode’s history.1
1960s
Senco opens its first manufacturing facility on Broadwell Road in Cincinnati, where it produces paper-taped framing nails and coil nails.1
1983
US Patent 4,403,722 (filed 22 January 1981, issued 13 September 1983) is granted to Milovan Nikolich of Chicago for a fastener driving tool powered by combustion of a fuel and air mixture.1
2006
Lipscomb and colleagues report that among 772 apprentice carpenters, 45% had sustained a nail gun injury and that tools with contact trip triggers had twice the injury rate of sequential-trigger tools.1
2007
CDC reports about 37,000 nail-gun injuries a year treated in emergency departments in 2001–2005, 40% of them to consumers.1 2
2015
Lipscomb, Nolan and Patterson report that in 2010–2013 surveillance acute injury risk was 70% higher with contact trip triggers, and that musculoskeletal risk was comparable between the two trigger types.1

Where the sources disagree

Who made the first pneumatic nail gun, and when?

Morris Pynoos built the first pneumatic nailer in 1944 for the Hughes H-4 Hercules aircraft; no photographs of it were found.1
Don Carlson, Journal of Light Construction
Bill Burnison’s Nu Matic Nailer of 1951–52 was the first commercially successful portable nailing machine for job-site construction.1
Don Carlson, Journal of Light Construction
Paslode’s Gun-Nailer of 1964 was the first commercially accepted pneumatic nailer.1
Paslode company history, as relayed by Tools in Action
Senco created the world’s first pneumatic staplers in the 1940s.1
SENCO (company history)

Gaps in the record (6)

The Pynoos nailer has no patent or photograph in the sources read; the 1944 date rests on Carlson’s account.
Carlson’s history is an industry insider’s account adapted from a self-published book; it has not been checked against patents.
Paslode’s 1959 and 1964 dates come from a trade site relaying company history and have not been matched to patents or catalogs.
The launch year of Paslode’s Impulse combustion nailer has not been sourced from a readable primary record; the Nikolich patent of 1983 is the earliest document read, and its assignee line is not clearly legible in the scan.
The NIOSH publications “Nail Gun Safety: A Guide for Construction Contractors” (2011-202) and the CDC MMWR report could not be fetched from here (the CDC site refused access), so the injury findings are cited through the journal abstracts held by Scholars@Duke and a trade-press summary of the MMWR report.
Standards slugs, including the ANSI nailer standard and EN 792-13, have not been read.

What matters when buying

Judged on cited evidence only; the basis is stated beside each claim. No brand is recommended here.

Trigger system. A sequential (restrictive) trigger is supported by published injury evidence over a contact (bump) trigger, which is supported only for experienced users in production work.
Air consumption and operating pressure relative to the compressor that will feed the tool.

Evidence

In a study of 772 apprentice carpenters, the injury rate was twice as high with contact trip triggers as with sequential triggers after adjusting for experience and training (rate ratio 2.0, 95% confidence interval 1.2 to 3.3).1
In 2010–2013 surveillance of union carpenter apprentices, acute injury risk was 70% higher with contact trip than with sequential triggers, while the musculoskeletal injury rates were comparable (0.09 against 0.08 per 10,000 hours); the authors conclude there is no justification for failing to use the safer trigger.1
Senco’s own manual recommends sequential actuation for most applications and strongly recommends it for less experienced users and tight or awkward spaces, reserving contact actuation for experienced professionals.1