Grease gun anatomy is a science unique to mechanics and machinists. If you need to use a grease gun for a repair or in your job, it helps to know the make-up of the tool. In order to understand the gun’s construction, the tool needs to be dissected and the types of guns reviewed.

Grease Gun Anatomy - Understanding How a Grease Gun Operates

Part of understanding grease gun use is to familiarize yourself with grease gun anatomy.


3 Types of Guns

Grease guns are featured in three types of styles with respect to use. Guns can be powered by hand, air, or electricity. Manual or hand-operated guns are made with a pistol or lever grip. The gun you use then depends on the application and personal preference. One major difference in grease gun use is how the gun is loaded. Guns are filled with lubrication by suction fill, bulk, or cartridge.

Manual Grease Guns

The manual grease gun is the most commonly used type of gun. It supplies about 1.28 grams of grease for each pump. The grease is transmitted into an aperture from a hand pump. The manual gun with a pistol grip can be operated by one or two hands. This type of gun provides about .86 grams for each pump.

Pneumatic Grease Guns

The pneumatic grease gun uses a pistol grip and compressed air. The air is directed inside the gun with a hose using a trigger.

Battery-Powered Guns

Grease guns powered by a battery feature a pistol-grip design. Guns of this type work similarly to pneumatic guns. This type of gun is manufactured without a cord.

Why You Should Fully Familiarize Yourself with Grease Gun Anatomy and Use

Understanding grease gun anatomy is essential to using grease as the material clings to engine parts or components without leaking away. Therefore, proper grease gun use should be fully understood. When a technician or mechanic fully understands grease gun anatomy and use, machines and bearings work better as well as last longer.

Connectors, Couplers, and Adaptors

A grease gun normally comes with a standard hydraulic coupler. Adapters may be used as well in the following configurations:

  • A 90-degree adapter is typically used for confined spots that require a bend of 90 degrees.
  • Needle-end adapters supply a precision amount of grease for tight spots.
  • Three-jaw swivel couplers offer various locking positions for numerous applications.

Hoses and Tubes

The choice to use a fixed tube or adaptable hose depends on a machine’s ease of location and the type of gun used. For instance, a hard-to-reach area would benefit from the use of a hose while a lever-style gun would work better with a fixed tube.


Meters for grease guns can be retrofitted into a gun to maximize lubricant use. The use of plastic caps prevent debris and corrosion. Color-coding the caps can help prevent cross-contamination. Sonic and ultrasonic devices are also available for use.

Fittings for Grease Guns

Fittings for grease guns go by a number of names, including grease nipple, Alemite fitting, or Zerk fitting. The fitting represents the point where the grease connector is attached. The mostly commonly used fitting is the hydraulic grease fitting, which is featured in an angled or upright design.  If a large amount of grease is added, a button-head fitting is advised. Flush type fittings are preferred in restricted spaces. A pressure-relief vent fitting is recommended to prevent higher pressures that can lead to damaged seals.

High Pressures

Part of grease gun anatomy involves knowing the proper amount of pressure to apply. A high-pressured manually operated gun delivers from 2,000 to 15,000 psi. Bearing seals should be greased with no more than 500 psi of pressure. So, be careful about applying pressure as too much force leads to collapsed shields on bearings and environmental and safety problems.

Applying Too Much or Not Enough Grease

It is essential to know the precise measure of grease needed for greasing applications. Damaged motor windings and seals, fluid friction, and higher energy consumption result from over-greasing. Increased contamination and fiction wear surface when parts are under-greased.

A Review of Grease Gun Anatomy

Manual Designs

In manual designs, the lever of a grease gun is used for hand-pumping the grease from the gun’s barrel into a tube or hose. The trigger and handle are used in manual grease guns in the same way. The barrel of the gun is the exoskeleton of the gun and contains the grease tub or grease that is derived from bulk storage. The grease tube or cartridge is a type of housing that is replaced when the grease has been used.

Operational Fittings

The hydraulic connector or coupler of the gun is a linking point that holds a fixed tube or hose that is affixed to the grease gun’s head. The filler nipple represents the grease injection point from a filler pump. An air-release nipple permits the escape of air after the lubricant has been added to the gun and pumped into its head. The spring on the gun supplies the pressure onto the plunger.

Rods and Handles

The follower rod assists the plunger maintain a uniform direction as it holds pressure on the bottom part of the tube of grease. The rod is also used to pull back the spring before the insertion of a new tube. The follower handle offers holding power when the follower rod or plunger rod is pulled before tube insertion. A fixed tube may be used interchangeably with a hose to ease the use and positioning of a coupler or connector. Fixed tubes are inflexible forms of hoses.

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