9. Preparation of Apparatus
9.1 Cleaning Penetrometer Cone - Clean the penetrometer cone carefully before each test with a soft cloth or paper wiper. The wiper can be dampened with an appropriate volatile gum-free solvent, when necessary, to remove any grease remaining on the cone. The solvent should have no effect on the cone surface. While cleaning, do not rotate the cone, as this can cause wear on the release mechanism. Bending of the cone shaft can be avoided by holding the cone securely in its raised position while cleaning.
9.2 Cleaning Penetrometer Shaft - The penetrometer shaft should be cleaned periodically with a soft cloth or paper wiper dampened with an appropriate volatile gum-free solvent to remove any oil, grease, or dirt buildup. Foreign materials on the penetrometer shaft can cause drag on the shaft assembly, possibly causing erroneous results.
9.3 Any other cleaning or adjustments to the apparatus should be done in accordance with the equipment manufacturer's recommendations.
10. Calibration and Standardization
10.1 Proper operation of a grease penetrometer can be checked by running periodic tests with a grease of known consistency. NLGI reference grease has been found to be suitable for this purpose, since multiple laboratories run tests on this material to generate the data reported for it. Data on this material is provided by NLGI with the purchase of the grease.
