Q. Would you please advise if there is an alternate industry standard specification for the following European grease:
Lacerta CL2X DEF STAN 91-27/1
Renolit CL2X DEF STAN 91-27/1
Thank you in advance for your support.
A. The British military specification DEF STAN 91-27 / 1 has been superseded by DEF Stan 91-27 / 2. Only one product meets the requirements of issue 2 and that is Fuchs Renolit CL2X.
Q. I would like a crossover from a Chinese grease, to a grease I can purchase locally. Below, please find the numbers from the container.
3HAO ZHEN KONG ZHI
A. We have no details on the grease you are currently using and can not make a recommendation. We suggest you contact the supplier of the equipment you want to lubricate for a grease recommendation.
We do recommend you use caution when replacing greases; the most common effect is that the mixture may become soft and not provide the desired amount of lubrication. If possible the older grease should be removed before the new grease is added; if this is not possible then the new grease should be frequently applied to remove the old grease.
Q. What is an acceptable design criterion for sizing spherical bearings based on maximum allowable pressure without exceeding the boundary lubrication capacity of grease for use in heavy duty industrial and off road applications? The equipment is working under adverse conditions such as exposure to slow, heavily-loaded applications and shock-loading conditions. The allowable pressure is calculated by dividing the load (force) by projected area of bearing (shaft diameter times bearing length). Relating to the above question, how does the type of grease and frequency of greasing the bearing factor into the design?
A. Bearing selection can come from design data offered by bearing manufacturers; among these data are sizing and minimum base oil viscosity charts. Seal integrity along with a trial period are among the details to be considered in establishing a re-lubrication interval. The greaseâ€™s thickener type is likely not as important as having extreme pressure and rust protection properties; a synthetic base oil may be needed for low temperatures.
Q. Have any tests been done on the temperature effect on worked penetration of grease? Our lab inadvertently performed a (D 217) test at 20C instead of 25C and naturally the results were lower than expected. I am wondering if the 5C difference could have had such a large impact (277 versus 310-360 expected)?
A. The ASTM D 217 test should be conducted at 25 degrees C. We would expect the penetration at 20 degrees to be a few points more firm but not the great difference you have found.
Q. I am looking for a specification to define a NLGI #2 Lithium Based Grease. We build large custom machines and use this type of grease for lubrication of our linear bearings. We have just shipped a machine to the UK and our customer has a corporate arrangement with a local supplier to furnish all lubricants on the site. The supplier claims to need more information that just NLGI #2 to select the appropriate grease.
A. A suitable grease for linear bearings depends on the application â€“ for some applications the grease could be the commonly available products meeting the NLGI Grease Classification GC-LB. A grease meeting GC-LB will have good fretting wear protection along with resistance to other forms of wear, rust, corrosion, oxidation and compatibility with some commonly used elastomers. However, if a particular operating detail must be observed such as a low vapor pressure lubricant or compatibility with a nonmetallic is called for then the grease selection becomes more specific. We suggest you advise the grease supplier of the operating temperatures, use of any nonmetallic, the need for low volatility such as in a clean room or any other details of the application.
Q. I work for a heavy equipment rental company in Phoenix, AZ. In our fleet we run a series of medium to large series hydraulic excavators. We have been experiencing a large number of bucket pin joint failures. This has caused us to take a closer look at the lubricating grease we are using. We are currently using a lithium complex 3% moly grease on all of our machines including excavators. It is now recommended that we use a calcium sulphonate complex 5% moly grease. Keeping in mind that we only grease our machines prior to every rental and not knowing which type of grease our customers might use, will we benefit from us greasing with the calcium sulphonate 5% to help reduce the types of failures we are experiencing. Also, are we going to experience any compatibility problems from using the C.S.C. 5% moly?
A. Mixing of different types of grease may give rise to the possibility that the two greases are not compatible with the mixture becoming soft the most common result. While we have not been present to observe your specific grease loss problem, incompatible greases may be the cause. One solution would be to advise your customers that mixing grease is not a good practice unless they are known to be compatible. Inform them which grease you use. We do suggest you follow the recommendation of the equipment manufacturer for the type of grease to use.
Q. My garage door works on an overhead â€œrailâ€ with ridges in it. It squeaks and often catches and wonâ€™t open. What type of grease can I use on it that will cause it to work easily and yet not â€œmeltâ€ because I live in the Palm Springs desert area and it gets very hot here in the summer?
A. We suggest you follow the grease recommendations of the doorâ€™s manufacturer. Before applying any new grease all of the current grease should be removed. The â€œmeltingâ€ you have observed could be from mixing different types of greases which resulted in an incompatible mixture that became soft.
The NLGI believes the information contained herein to be accurate, but makes no representation, guarantee, or warranty, express or implied, about the accuracy, reliability, or completeness of the information or about the fitness of contents herein for either general or particular purposes. Persons reviewing this information should make their own determination as to the materialâ€™s suitability and completeness for use in their particular applications.