Grease Gun

Introduction

This article is about the lubrication tool called the “Grease Gun.” Grease guns are a standard tool in the garage and workshop for lubrication. Grease guns apply lubricant through an aperture to a specific point. This could be anything from a grease cart to a grease fitting or nipple. The grease nipple is the channel that leads to the lubrication location. The image of air operated grease gun is shown in Fig-1.

Fig-1 Air Operated Grease Gun

Types of Grease guns

There are four types of grease guns and they are:

1. Hand-powered grease gun: The grease is forced out of the aperture using back pressure. This can be achieved by manually cranking the trigger mechanism. This applies pressure to the spring mechanism behind the grease which forces the grease through the aperture.
2. Grease gun with no trigger mechanism: This is another type of hand-powered grease gun where there is no trigger mechanism. The grease is forced into the aperture by applying the back pressure which is done by pressing on the butt of a grease gun. A piston slides through the body of the tool, and the piston pumps the grease out of it.
3. Pneumatic grease gun: In this type, the compressed air is directed at the gun via hoses and the air pressure serves to force the grease through its aperture.
4. Electric grease gun: In this type, it uses an electric motor to drive an electric grease pump.

Grease Guns and Machine Health

1. High Grease Gun Pressure: The high-pressure manual grease gun can deliver between 2,000 and 15,000 psi. Greasing too hard can cause damage to the bearing seals. They rarely tolerate more than 500 psi pressure, however, high grease gun pressure can cause bearing shields to collapse and damage.
2. Re-lubrication Interval: It is essential to manage the frequency of regreasing to avoid serious machine health issues and to maintain optimal conditions. If the frequency is too high, it can lead to lubricant starvation which causes wear, friction, and grease contamination. Excessive grease consumption, safety, and environmental concerns may be an issue if the frequency is too low.
3. Overgreasing or Undergreasing: To avoid over or under-greasing, it is essential to determine the precise amount of grease required for your application. Overgreasing can damage the motor windings and seals causing environmental issues and also increasing fluid friction. Increased fluid leads to higher heat generation, which in turn increases grease oxidation rates and increases energy consumption. Also, bearing starvation is a sign of under greasing. This causes friction wear and increases contamination. So, we have understood that both over-greasing and under-greasing can damage the applications or bearings. So understanding the proper quantity of lubricant that should be used is vital.

Grease gun output measurement

Maintenance teams typically own many grease guns with different types, and models. This could cause problems related to grease because of cross-contamination and insufficient information about each grease machine’s capacity per stroke. Grease guns have been known to differ in the grease produced between 0.5 grams and 3 grams. This variation is based on various factors like the model, type, and age of the grease gun.

To solve this issue, OEM manuals should contain greasing and re-greasing instructions for the bearings. These OEM instructions can aid in deciding how often one should grease their bearings and how much grease one should use to get ultimate lubrication benefits. Also one must estimate what amount of grease is released by the guns for each stroke. To accomplish this, they must continuously pull 10-strokes of grease, and measure the weight of the grease. Once they have this number, it should be divided by 10 to get the approximate amount of grease in stroke for the grease gun.

It is recommended to be aware that even the same guns of identical models may differ in the grease quantity they release whenever they stroke. So, each grease gun needs to be marked with the weight of the grease released per stroke and calibrated every few months. Also one should be sure to use the same grease when calibrating and in the time of re-greasing the application. A device for measuring the amount of grease is an alternative option that does not require calibration. It is connected between the grease gun’s hose and the coupler used to join the Zerk fitting. If the operator is pumping fluid through the tube, the metering device gives an electronic readout on a small screen that measures the volume or weight in ounces or grams. The grease metering device is shown in Fig-2.

Fig-2 Grease metering device

Grease Gun Best Practices

• Based on the specified grease gun’s delivery volume, calculate the appropriate amount of grease required for the re-lubrication.
• To flush out old grease and prevent excessive pressure from building up, use a vent plug at the bearing’s relief port.
• To ensure that no contaminants are introduced to the grease gun, one must be extremely careful when loading grease and use a cartridge to ensure that no metal particles get into the grease.
• To identify the grease to be charged, ensure the grease gun is clearly labeled and use only the designated grease for each grease gun.
• Before using the grease gun, ensure the dispensing tube is clean. Before attaching the grease fitting, pump a little grease from the dispensing tube.
• Before attaching the grease gun, clean the grease fitting and replace damaged fittings. The grease-fitting caps are an excellent option to keep fittings clean. However, it is essential to clean the fittings before applying grease.
• Make sure that you use the correct grease at each grease point. Incompatibility problems can lead to bearing failure. It is essential to identify the grease to be used at lubrication points. This can be done using colored labels, adhesive dots, and paint markers.
• Grease guns should be kept in a dry and clean place. Grease gun clamps simplify storage and make it easy to organize. Cover the coupler with a cover to protect it from dirt and contaminants.
• Regular calibration of guns is necessary to ensure the correct delivery volume.

Points of caution when using a grease gun

• To avoid spraying, one should keep their face away from the discharge port. If they are too close to the tool, some undesirable substances, such as chemicals and machine dust may escape.
• Make sure to read the instructions and do maintenance regularly.
• When installing or disassembling, always wear protective gear (protective gear, shoes).
• Perform a daily inspection.
• Follow the instructions strictly.
• If one feels that it is unsafe or unusual, stop using it without its proper knowledge.
• Avoid water and dust getting into the machine. These impurities can affect the quality of the grease.
• There is a possibility that oil could be spilled during operations so use caution.

About Author: The article is written by Riya Veluri, an editorial team member of Industrial Lubricants. After her graduation, Riya works as a website developer & SEO specialist in the Lubrication & Tribology Industry & writes technical articles on Lubricants, Lubrication, Reliability & sustainability. You can reach us at [email protected]