Practice Test Geeks(CLS) Certified Lubrication Specialist Practice Test
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Grease Technology & Application Flashcards

7 cards from real CLS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Grease Technology & Application flashcards as text

  1. Which thickener type provides the highest dropping point among common grease thickeners?

    Answer: Bentone (clay)

    Bentone (clay or anhydrous calcium silicate) greases have no true dropping point as they do not melt; they degrade thermally rather than becoming liquid, giving them the highest effective upper temperature limits.

  2. What does the worked penetration test (ASTM D217) measure in grease?

    Answer: The depth a standard cone penetrates the grease after 60 strokes of a worker

    Worked penetration (ASTM D217) measures how far a standardized cone penetrates the grease after 60 double strokes in a grease worker, which determines the NLGI consistency grade.

  3. What is the main advantage of calcium sulfonate complex grease over conventional lithium complex grease?

    Answer: Inherent EP and rust protection without requiring additives

    Calcium sulfonate complex grease provides inherent extreme pressure (EP) and anti-rust properties due to its unique thickener chemistry, without requiring separate EP and rust-inhibitor additives.

  4. In a centralized automatic grease lubrication system, what is a primary advantage over manual re-greasing?

    Answer: Delivery of smaller, more frequent grease quantities while equipment is running

    Centralized automatic systems deliver precise, small quantities of grease at frequent intervals while equipment is running, which maintains optimal lubricant film thickness and reduces waste and over-greasing.

  5. What is 'channeling' behavior in grease and why can it be beneficial?

    Answer: Channeling is when grease forms a channel allowing the bearing to run through the grease without churning it, reducing heat generation

    Channeling occurs when a bearing clears a path through the grease, allowing it to operate with minimal grease churning, which reduces energy losses and heat generation in high-speed applications.

  6. Which test method is commonly used to evaluate the water washout resistance of grease for wet environments?

    Answer: ASTM D1264 (Water Washout Characteristics)

    ASTM D1264 measures the water washout resistance of grease by exposing a greased bearing to a water spray at controlled temperatures and measuring the percentage of grease lost.

  7. What is the recommended practice when mixing two different grease types in a bearing housing?

    Answer: Mixing greases should be avoided; perform a compatibility test or completely purge old grease before switching

    Mixing incompatible greases can cause softening, hardening, oil separation, or loss of structure, so compatibility should be verified or old grease completely purged before introducing a new type.