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Millwright Level 1 > Lubrication > Flashcards

Lubrication Flashcards

1
Q

What are the three main types of friction?

A

Sliding, rolling, and fluid friction

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2
Q

This type of friction occurs when two surfaces slide over each other, such as in journal bearings, or pistons sliding in a cylinder

A

Sliding friction

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3
Q

This type of friction takes place when a spherical or cylindrical body rolls over a surface such as ball and roller bearings

A

Rolling friction

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4
Q

This type of friction occurs when there is no metal to metal contact and sliding occurs between the layers of oil within the film

A

Fluid friction

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5
Q

The reduction of friction to a minimum by the replacement of dry friction with fluid friction is called?

A

Lubrication

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6
Q

This theory thats that these forces cause unlike materials to stick together (polar attraction)

A

Adhesion

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7
Q

This theory states that these forces cause molecules of like materials to stick together

A

Cohesion

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8
Q

When the adhesive forces are strong in oil it’s said to be high in?

A

Oiliness or lubricity

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9
Q

What is the resistance to flow called?

A

Viscosity

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10
Q

Which viscosity is thicker and pours more slowly?

A

High viscosity

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11
Q

This is the most important property of lubricating oil

A

Viscosity

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12
Q

The higher the viscosity of the oil, the _______ the load it will carry

A

Greater

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13
Q

The higher the journal speed, the ______ the oil viscosity needed to carry a specific load

A

Lower

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14
Q

To minimize power losses, the oil should have the ______ viscosity able to carry the load on the bearing

A

Lowest

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15
Q

Choose the oil that has the desired viscosity at which temperature?

A

Operating temperature

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16
Q

Which two ways is viscosity measured?

A

Dynamic and kinematic

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17
Q

This viscosity is determined by measuring the force required to overcome fluid friction in a film or known dimensions. It’s used most frequently in bearing design and oil flow calculations

A

Dynamic or absolute viscosity

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18
Q

This viscosity is a measure of viscosity that is affected by the density of the oil. It is used to often compare lubricants when both are measured at the same temperature

A

Kinematic viscosity

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19
Q

The most common instrument used to measure viscosity is called?

A

Saybolt viscosimeter

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20
Q

The specific viscosity reaction of an oil whose temperature changes is indicated by what?

A

Viscosity index

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21
Q

The higher the viscosity index number, the ______ the change in viscosity due to temperature

A

Smaller

22
Q

The _______ forms and forces the shaft up toward the centre of the bearing

A

Oil wedge

23
Q

When the film of oil fails for a short time it is called?

A

Boundary or marginal lubrication

24
Q

This occurs when you over-lubricate a threaded hole and it presses the liquid causing the casing to crack

A

Hydraulic lock

25
Q

Additives are divided into these three main groups

A

Air control, water control, and load capacity

26
Q

This is the ability of a petroleum oil to separate from water upon standing

A

Demulsibility

27
Q

This is the ability of a petroleum oil to mix with water

A

Emulsibility

28
Q

These are added to the oil to reduce the rusting of ferrous parts

A

Rust inhibitors

29
Q

These additives are used for heavy load or shock load conditions

A

Extreme pressure (EP)

30
Q

Load capacity additives are separated into these two groups

A

Anti-wear and Extreme pressure

31
Q

What are the two types of oil lubrication systems?

A

Once-through/wasted oil system and Encloses

32
Q

Squirt cans, wick-feed oiler, and drip-feed oilers are which type of lubrication system?

A

Once-through

33
Q

Ring oiler, splash, oil bath, and re-circulating and which type of lubrication system?

A

Enclosed

34
Q

This type of lubrication is recommended for high-speed bearings and high-velocity roller chain

A

Oil mist lubrication

35
Q

This is usually made by thickening lubricating oils with a soap

A

Grease

36
Q

Soap content for general use greases range from what percent?

A

7-18%

37
Q

This type of grease is made by combining fatty acid with a base metal

A

Simple soap grease

38
Q

What is the most commonly used soap grease

A

Lithium and barium

39
Q

What type of grease is made by combining various types of soaps to extend the service life of grease

A

Mixed soap greases

40
Q

These greases are made from special soaps and are multi-purpose

A

Complex soap greases

41
Q

These greases are used to suit special conditions of temperature, environment or service life

A

Non-soap greases

42
Q

These greases are designed to allow one grease to be used instead of three or four separate grades

A

Multi-purpose greases

43
Q

This type of grease is designed for shock loading or high-local-pressure areas

A

Extreme-pressure (EP) greases

44
Q

How is grease consistency measured

A

Penetration numbers

45
Q

The NLGI ranges grease from softest to hardest with what numbers

A

000, 00, 0, 1, 2, 3, 4, 5, 6

46
Q

The temperature at which grease becomes fluid enough to drip is called

A

Dropping point

47
Q

Common grease dropping points range from

A

135 C (275F) to 182 C (360F)

48
Q

How high should the oil bath cover the bearing

A

Covers the bottom of the outer race, but does not cover the centre point of the lowest ball or roller

49
Q

What does over-oiling produce

A

Churning and a temperature rise

50
Q

Should you use oil or grease for high speeds

A

Oil

51
Q

Should you use oil or grease for heavy loads at low or medium speeds

A

Grease

52
Q

What are the three types of cutting oils

A

Straight, emulsifiable, and chemical

Millwright Level 1 (5 decks)

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