Millwright Red Seal Bearings Questions
100% Correct Solutions
What temperature (in Fahrenheit) is a bearing to be heated to in an oil bath, prior to
installation?
a. 248 to 250
b. 260 to 262
c. Always below 240
d. Always above 260 - ANSWER a. 248 to 250
What temperature (in Fahrenheit) is Babbitt poured at?
a. 650 to 700
b. 800 to 1000
c. 300 to 325
d. 575 to 775 - ANSWER a. 650 to 700
Pour point - from 343 to 371*C (650 to 700*F)
complete melting point - from 275-285*C ( 495 to 545*F)
Complete solidification point - from 25- 28*C ( 40 - 50F ) below the complete
melting point .
What is "creep" in a bearing?
a. The very slow rotation of the outer race
b. The movement of the bearing as it rotates out of the housing
c. A condition that allows for expansion of the pillow block due to heat
,d. The very slow rotation of the needles in a needle bearing - ANSWER a. The very
slow rotation of the outer race
What are gib joint bearings suited for?
a. Heavy loads
b. Light loads
c. Limited side loading
d. Strictly radial loads - ANSWER c. Limited side loading
High-speed bearings and roller chain use what type of lubrication?
a. Mist
b. Bath
c. Splash
d. Dry - ANSWER a. Mist
Pros to oil mist (not need to know for red seal )
Prevent the dust/moisture ingress into bearing housing, due to pressurized system
Increased Bearing Life
Lower friction and thus reduced bearing temperatures
Reduced maintenance, reduced handling, and spillage.
As the bearings operate in a thin film of oil, so less power is required.
Reduced Oil consumption (40% less & 50% of it can be recovered)
More environmentally friendly than the conventional lubrication system.
As the oil on the bearings is always new, it provides better lubricant properties.
In technical papers released by end-users and bearing manufacturers, as well as in
university research, bearings lubricated with oil mist have a longer life than
bearings lubricated with oil sump or grease. Users report from a 50% to 90%
reduction in lubrication-related bearing failures.
, How much oil is required to lubricate a ball bearing?
a. Enough to cover the entire bearing
b. Enough to cover ½ of the bearing
c. Enough to cover the outer race
d. Enough to cover halfway up the bottom rolling element - ANSWER d. Enough to
cover halfway up the bottom rolling element
In a multi bearing system, how many bearings are fixed?
a. All of them
b. Only 1 of them
c. None of them
d. At least two - ANSWER b. Only 1 of them
to prevent end float only 1 bearing on a shaft should be fixed axially in housing . It is
better to hold the bearing on the drive end . All other bearings on the shaft should have
axial clearance in the housing to allow movement. They are " free" or "floating "
bearings. this allows the shaft to expand and contract.
Where should the lubricant entry on a bearing be located?
a. On the high pressure point
b. On the low pressure point
c. Anywhere
d. Always at 90 degrees to the bottom - ANSWER b. On the low pressure point
What is the housing of a friction bearing called?
a. Base
100% Correct Solutions
What temperature (in Fahrenheit) is a bearing to be heated to in an oil bath, prior to
installation?
a. 248 to 250
b. 260 to 262
c. Always below 240
d. Always above 260 - ANSWER a. 248 to 250
What temperature (in Fahrenheit) is Babbitt poured at?
a. 650 to 700
b. 800 to 1000
c. 300 to 325
d. 575 to 775 - ANSWER a. 650 to 700
Pour point - from 343 to 371*C (650 to 700*F)
complete melting point - from 275-285*C ( 495 to 545*F)
Complete solidification point - from 25- 28*C ( 40 - 50F ) below the complete
melting point .
What is "creep" in a bearing?
a. The very slow rotation of the outer race
b. The movement of the bearing as it rotates out of the housing
c. A condition that allows for expansion of the pillow block due to heat
,d. The very slow rotation of the needles in a needle bearing - ANSWER a. The very
slow rotation of the outer race
What are gib joint bearings suited for?
a. Heavy loads
b. Light loads
c. Limited side loading
d. Strictly radial loads - ANSWER c. Limited side loading
High-speed bearings and roller chain use what type of lubrication?
a. Mist
b. Bath
c. Splash
d. Dry - ANSWER a. Mist
Pros to oil mist (not need to know for red seal )
Prevent the dust/moisture ingress into bearing housing, due to pressurized system
Increased Bearing Life
Lower friction and thus reduced bearing temperatures
Reduced maintenance, reduced handling, and spillage.
As the bearings operate in a thin film of oil, so less power is required.
Reduced Oil consumption (40% less & 50% of it can be recovered)
More environmentally friendly than the conventional lubrication system.
As the oil on the bearings is always new, it provides better lubricant properties.
In technical papers released by end-users and bearing manufacturers, as well as in
university research, bearings lubricated with oil mist have a longer life than
bearings lubricated with oil sump or grease. Users report from a 50% to 90%
reduction in lubrication-related bearing failures.
, How much oil is required to lubricate a ball bearing?
a. Enough to cover the entire bearing
b. Enough to cover ½ of the bearing
c. Enough to cover the outer race
d. Enough to cover halfway up the bottom rolling element - ANSWER d. Enough to
cover halfway up the bottom rolling element
In a multi bearing system, how many bearings are fixed?
a. All of them
b. Only 1 of them
c. None of them
d. At least two - ANSWER b. Only 1 of them
to prevent end float only 1 bearing on a shaft should be fixed axially in housing . It is
better to hold the bearing on the drive end . All other bearings on the shaft should have
axial clearance in the housing to allow movement. They are " free" or "floating "
bearings. this allows the shaft to expand and contract.
Where should the lubricant entry on a bearing be located?
a. On the high pressure point
b. On the low pressure point
c. Anywhere
d. Always at 90 degrees to the bottom - ANSWER b. On the low pressure point
What is the housing of a friction bearing called?
a. Base
