The grease gun gets its name from exactly what it looks like: a gun that shoots grease. The tool’s pistol-grip handle, cylindrical barrel, and trigger-style mechanism give it a strong visual resemblance to a firearm, and since its job is to force grease into machinery under high pressure, the name stuck naturally from its earliest days in the 1920s. The connection between the tool and guns runs both directions, too. During World War II, the M3 submachine gun earned the nickname “Grease Gun” because soldiers thought it looked like the mechanic’s tool.
How the Tool Was Born
The grease gun traces back to 1916, when a young man named Arthur Gullborg was responsible for lubricating die-casting machines at the Alemite Die Casting and Manufacturing plant, where his father was part owner. At the time, the only way to keep machines lubricated was to manually pour oil into refilling cups several times a day. The work was hot, dirty, and exhausting. Gullborg came home after every shift covered in oil and grime.
Frustrated with the process, he began experimenting with better methods. His breakthrough was a system with three parts: a fitting (connector), a hose (duct), and an applicator (pump). The applicator would push grease under pressure through the hose to the lubrication points on a machine. Bearings could be greased faster, more thoroughly, and without the mess. By 1918, father and son had formed the Alemite Lubrication Company to sell the system commercially. Alemite catalogs from that era already used the term “grease gun” to describe the handheld applicator.
Why “Gun” Specifically
The word “gun” wasn’t just marketing flair. The tool genuinely operates like one. You load a cartridge of grease into a cylindrical tube (the barrel), aim the nozzle at a lubrication point, and squeeze a trigger or pump a lever to fire grease out under pressure. A manual grease gun can generate up to 15,000 psi, which is a staggering amount of force from a handheld device. For context, most bearing seals can only handle about 500 psi.
The pistol-grip style, which lets you operate the tool with one hand, reinforced the gun analogy even further. Lever-action models require two hands, but pistol-grip versions mimic the feel of pulling a trigger. Even modern battery-operated and air-powered versions maintain the same basic shape: a long tube with a handle and a nozzle at the end.
The Fitting That Made It Standard
The grease gun became truly widespread thanks to a small but critical companion part. Before the late 1920s, most machinery bearings were lubricated through simple cross-drilled holes, sometimes with a basic cap or cup on top. Lubricant got in through gravity or a finger push, which was slow, messy, and inconsistent. Alemite had been selling ball-check valve fittings since 1919 to accept pressurized grease from their guns, but these early fittings were prone to dirt and required a precise angle to connect.
In 1929, an inventor named Oscar Zerk patented an improved fitting and assigned the patent to Alemite. The Zerk fitting was smaller, sealed more cleanly against contamination, and worked even when you approached it at a slight angle. This made the grease gun dramatically easier to use in tight spaces. Automakers began installing Zerk fittings at every lubrication point on car and truck chassis, and the grease gun became a fixture in every garage and service station. You’ll still find Zerk fittings on equipment today.
The Military Nickname That Went the Other Way
The name’s most famous crossover happened during World War II. The U.S. military introduced the M3 submachine gun in 1942 as a cheap, disposable weapon made from stamped and welded metal parts. Soldiers immediately started calling it the “Grease Gun” or “the Greaser” because its tubular receiver, cylindrical shape, and crude construction looked remarkably like the mechanic’s tool they already knew from civilian life. The M3 fired .45-caliber rounds from a 30-round magazine and was intentionally designed to be manufactured at minimum cost, then discarded when it broke. Its rough, industrial appearance only strengthened the comparison.
This nickname became so widespread that many people today encounter the term “grease gun” in a military context first and wonder about the connection. But the tool came first by more than two decades. The weapon inherited the name, not the other way around.
From Workshop Slang to Universal Term
By the 1930s, the Smithsonian Institution was already cataloging Alemite’s pneumatically powered grease guns as significant industrial artifacts. The tool had transformed maintenance across manufacturing, construction, agriculture, automotive repair, aviation, marine, and mining industries. What had started as one young man’s solution to a miserable daily chore became standard equipment worldwide.
The name endured because it’s simply accurate. The tool looks like a gun, operates like a gun, and delivers its payload with enough force to damage components if you’re not careful. Unlike many tool names that feel arbitrary, “grease gun” tells you exactly what the thing does and how it does it the moment you hear it.