Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/335762
grease guns and lubrication. A grease gun is a deadly weapon capable of "kill- ing" your equipment. Grease guns can produce up to 15,000 psi per stroke (shot); however, most bear- ing lip seals are unable to withstand more than 500 psi. Because of this, grease guns can generate significant pressure and, if improperly used, can ultimately blow out the seals designed to protect the bearings from external contaminants. When asked why there was so much grease ooz- ing out of a bearing, an operator once replied, "If one shot is good and two is better, then isn't 50 won- derful?" No! A few well- targeted rounds are often more effective than "spray and pray." Overfilling bear- ing cavities can create major issues: Grease is forced outside the seals (path of least resistance) as the equipment heats up, and it is exposed to contaminants and moisture. When the equipment cools, the con- taminated grease is sucked back into those same bear- ing cavities (part of thermal expansion and contraction) and can cause damage to the equipment. Overfilling the cavities also creates ad- ditional heat. It's essential that grease is used as a lubricant because it adheres to equipment's moving surfaces without easily dripping or flowing away like oil does. Grease is a semifluid-to-solid mix- ture of a fluid lubricant and a thickener and may contain additives. Lubricants used in construction are either mineral oil (petroleum- based) or synthetic oil. Most grease today is composed of mineral oil blended with a soap thickener. The dif- ference between normal oil- based grease and organic grease is that organic grease contains no paraffin or oil by-products. The organic July 2014 | EquipmentWorld.com 44 maintenance | continued On construction equipment, grease should be applied at a 90-degree angle leading to the load zone. Grease guns come with a variety of adaptors and couplers for different jobs and angles of application. Graphic source: Bennett Fitch, Noria. Graphic source: Bennett Fitch, Noria. Figure 2 Anatomy of a grease gun. Figure 3 Figure 4 Graphic source: Bennett Fitch, Noria.