Good Greasing Is a Feeling

Detail view of cylindrical roller bearing.

Your grease-gun technique plays a major role in determining how well you deliver the correct amount of clean lubricant to a bearing cavity.

Over the course of the past 40 years or so, I have been in many plants and industries and witnessed the effects of many premature lubrication failures—the overwhelming majority of which involved manual greasing. When asked if formal grease-gun training has ever been provided during their career, only a handful of maintainers have ever responded positively.

Bannister on Lubrication

Listen to this podcast with Ken Bannister in which he further explores grease-gun techniques and how to consistently deliver the proper amount of grease to a bearing.

Grease-gun use falls into the same category as hand washing. Until the recent spate of public campaigns to combat contact ailments, many of us, including myself, have only lately been taught to wash our hands correctly. The reality is that manual greasing, as in hand washing, has many nuanced facets attached to its correct use that must be performed if the act is to be consistently successful.

The grease gun’s “connect and pump” theory is overwhelmingly simplified when compared with the necessary actions required to grease effectively. The effects of poor manual-greasing control are exacerbated when lack of training is coupled with the mythical belief that if a little lubrication is good, then a lot of lubrication must be better, and the all-time number-one job plan instruction “lubricate as necessary”—perpetuated by equipment O&M (operations and maintenance) manuals and work planners alike.

Manual greasing has its place in a lubrication program, but requires an “engineered” and disciplined approach to its use if it is to effectively extend bearing life. An effective manual-greasing program must be built on four simple cornerstones:

• consolidation—minimum number of grease products
• standardization—all grease guns are the same make and type
• cleanliness
• restraint—nuanced and controlled greasing action.

Consistent, controlled

Ideally, bearing cavities need only contain between 40% and 50% of the grease capacity to effectively lubricate the bearing. Then, when every bearing requirement and application frequency is calculated according to size, speed, load, and usage, and all grease guns are standardized to a single design, the grease gun “shots per bearing” number can be calculated and a formal program instituted.

What happens when there is no formal greasing program, or any money or expertise available to the lubricator or maintenance staff? In those types of situations, maintainers can exercise control over greasing actions that will considerably extend bearing life over an ad-hoc greasing approach by consistently following, in order, a few simple steps.

Step 1. Action check:

Check the work order or machine plate to determine:

• grease point location (if numbered or colored)
• amount of grease required per grease point (only if some grease-point engineering has taken place)
• grease specification matches the grease found in the grease gun.

If this information is missing, compile a data page in a lubrication notebook for each machine and stay with a consistent standard manual-grease until a product-consolidation program has taken place.

Step 2. Pre-clean:

Clean grease fitting(s) to be greased with a clean lint-free cloth. A lint-free cloth is usually made from a cotton fabric with sewn and overlapped edges. The fabric is close woven and does not readily ‘shed,’ or release, fabric fibers. Purchase or rent lint-free mechanic’s cloths from a cleaning or safety supply house. Mechanic’s cloths can be cleaned and reused over and over again. Disposable lint-free paper-based products are also available.

Rag-style cloths made from discarded garments are not recommended for wiping grease nozzles or fittings. Rags are cut or torn to size and can be made from any fabric type, including wool (wool fibers are easily shed and can roll themselves into pill balls). The torn and cut fabric edges easily release errant fibers that can adhere to the grease fitting or grease nozzle and then be injected into the fitting. Fibers can be abrasive and promote premature bearing wear.

Step 3. Prepare gun for greasing:

Before attaching it to a fitting, ensure that the grease gun is charged with grease, primed, and cleaned.

For a trigger-style grease gun…

• Clean fitting(s) to be greased with a clean lint-free cloth.
• Slowly squeeze trigger toward grease-gun barrel until the grease discharges approximately 1/4 in., or 6 mm, of grease from the end of the grease-gun nozzle.
• Wipe clean the end of the grease-gun nozzle with a clean lint-free cloth.

For a lever-style grease gun…

• Collapse lever to the barrel causing grease to discharge from the nozzle.
• If the lever is already collapsed, open lever and collapse, discharging a shot of grease from the grease nozzle.
• Wipe clean the end of the grease-gun nozzle with a clean lint-free cloth.

The gun is now ready. Continue to Step 4 immediately. If the gun is dropped or placed down, nozzle contamination of the grease-gun nozzle is likely and Step 3 must be repeated.

Step 4. Connect nozzle to the grease nipple:

To connect to a zerk-style grease fitting, align the grease gun nozzle with the fitting and push the nozzle firmly on to the fitting. Ensure that the nozzle is securely connected by slowly rocking the nozzle side to side and trying to gently pull the grease gun away. If resistance is felt, the grease nozzle is connected. 

To connect with a DIN-button-head-style fitting, slide the grease-gun nozzle’s location slot across the button-shaped head of the grease fitting until it comes to a firm stop

Step 5. Deliver lubricant: If the bearing grease calculation or grease-gun shot-size output is unknown, it is difficult-to-    impossible to know exactly how much grease is required to achieve a 40% to 50% cavity fill. If this is the case, the best tactic is to “feel” the grease into the bearing cavity until slight resistance or back pressure is felt against the trigger, or lever, signaling the bearing cavity is now full. Warning! Pumping beyond this point will almost certainly blow the bearing seal and create an open channel for contamination to get into the bearing cavity and cause premature failure.

For a trigger-style grease gun…

• Gently squeeze the trigger (use only the finger tips) toward the grease-gun barrel and “feel” grease into the bearing until resistance or back pressure is felt.
• Relax hand and allow the trigger-return spring to reset the trigger back to the loaded position.
• Repeat if more lubricant is required.

For a lever-style grease gun…

• Gently push the lever toward the grease-gun barrel using the palm of the hand and “feel” grease into the bearing until resistance or back pressure is felt.
• Pull lever back to the fully extended position and repeat if more lubricant is required.

Note: One squeeze action of a trigger-style grease gun and one lever action of a lever-style grease gun equals one shot of grease.

Step 6. Disconnect grease gun:

For a zerk-style fitting, rock the grease gun nozzle side to side and firmly pull the gun away from the fitting. When using a DIN button-head-style fitting, slide the grease-gun nozzle’s location slot across the button-shaped head of the grease fitting in a reverse manner until disengaged.

Step 7. Post-clean:

Wipe residual grease from the grease nozzle and grease fitting using a lint-free cloth.

• Good grease-gun hygiene automatically makes you part of the solution. Remember that greasing is a blind act requiring a gentle touch and active restraint. EP

Contributing editor Ken Bannister is co-author, with Heinz Bloch, of the book Practical Lubrication for Industrial Facilities, 3rd Edition (The Fairmont Press, Lilburn, GA). As managing partner and principal consultant for Engtech Industries Inc. (Innerkip, Ontario), he specializes in the implementation of lubrication-effectiveness reviews to ISO 55001 standards, asset-management systems, and training. Contact kbannister@engtechindustries.com, or telephone 519-469-9173.