Millwright Level 2 - Bearings Practice Solution Manual Fully Solved
What are the principle parts of a friction bearing housing? - Answers Base, Base bolt slots, cap and cap
bolt holes.
What are friction bearing housings made from adn what factors influence the choice of housing? -
Answers Cast Iron, Cast Steel, Fabricated Steel.
Choice depends on the Load, The Rotational Speed, the Direction of Pull and the Support Design
How are friction bearing dimensions expressed? - Answers In a fraction of their nominal size.
Do all new bearings of the same shaft size have the same base-to-eye measurement? - Answers If they
are from the same manufacturer.
What factors influence the choice of bearings? - Answers Load, Rotational Speed, Direction of the Pull
and support Design
What are the applications for the following bearings?
a)Solid Bearings
b)Split bearings
c)Angle bearings
d)Integrated Bearings - Answers a) Where Speed and Load are low. Where load is applied on the top
part of the bearing.
b) Where load is applied on the bottom portion of the bearing. Different bolt numbers for loads.
c)When load is applied parallel to, or at a slight angle to, the horizontal. Or when the bearing is mounted
on the vertical support
d)Where the bearings are an integral part of the machine.
How does friction bearing joint design affect its integrity? - Answers Position of the top half may affect
the bearing tolerances and load positions.
What qualities should a good bearing material have? (5 points) - Answers Softer than the shaft material,
low coefficient of friction, wear-resistant, a good heat conductor and remain relatively stable with heat
changes, readily available.
List Metals generally used in bearing liners and their applications. (5 points) - Answers Babbitt - for
general use
Brass (copper zinc alloy) - for higher speeds and heavier load than babbit
, Bronze (coper tin alloy) - for higher speeds and heavier loading than babbitt
Aluminum - hydraulic pumps
Sintered Bronze - Porous bronze with a built in oil supply. 2:1 ratio.
What characteristics of nylon polyurethanes and phenol laminates affect their applications? - Answers
Heat, , water saturation.
What is the hardest and toughest babbitt made from? - Answers Tin (90%)
How does overheating affect babitt? - Answers Service life is greatly reduced
How is babbitt held in bearing casting? - Answers Holes or slots.
Describe the procedure for pouring a babbitt bearing using a mandrel. (6 Steps) - Answers 1. Gather
Equipment ( oxyacetylene torch putt pliers, babbitt)
2. Fit the torch with a large tip and melt out the remaining babbitt in the casting
3.Smoke the shaft with a straight acetylene flame.
4.Put a putty dam around the shaft and bearing
5. Hold the babbitt with the pair of pliers
6. Melt it into the bearing with the torch.
What must be checked when fitting a bearing? (4 points) - Answers surface finish area of contact,
running clearance, lubrication entry, and grooves
Describe the purpose of tinning. - Answers To secure a thin skin of babbitt to a metallic backing.
Describe the tools used to fit a friction bearing. - Answers Scraper, files, groove chisels.
Describe procedure for fitting a bearing. - Answers 1. Chamfer the top edges or cut an oil groove
2. check bearing for contact by coating mandrel in bluing and rotating mandrel
3. Shave down high spots indicated by bluing
Describe the procedure fro shimming a bearing to the correct amount of clearance. - Answers Insert
shims, make sure they do not make contact with the shaft or the chamfer. Tighten bolts to specs and
rotate the shaft. Add shims or realign the cap.
Describe the procedure for checking bearing clearance with a dial indicator, Pastigage and lead wire. (3
points) - Answers 1. Place indicator on both ends of the shaft and adjust to acquire an even reading.
2. Insert plastigage and tight cap to proper torque and measure width to determine clearance.
What are the principle parts of a friction bearing housing? - Answers Base, Base bolt slots, cap and cap
bolt holes.
What are friction bearing housings made from adn what factors influence the choice of housing? -
Answers Cast Iron, Cast Steel, Fabricated Steel.
Choice depends on the Load, The Rotational Speed, the Direction of Pull and the Support Design
How are friction bearing dimensions expressed? - Answers In a fraction of their nominal size.
Do all new bearings of the same shaft size have the same base-to-eye measurement? - Answers If they
are from the same manufacturer.
What factors influence the choice of bearings? - Answers Load, Rotational Speed, Direction of the Pull
and support Design
What are the applications for the following bearings?
a)Solid Bearings
b)Split bearings
c)Angle bearings
d)Integrated Bearings - Answers a) Where Speed and Load are low. Where load is applied on the top
part of the bearing.
b) Where load is applied on the bottom portion of the bearing. Different bolt numbers for loads.
c)When load is applied parallel to, or at a slight angle to, the horizontal. Or when the bearing is mounted
on the vertical support
d)Where the bearings are an integral part of the machine.
How does friction bearing joint design affect its integrity? - Answers Position of the top half may affect
the bearing tolerances and load positions.
What qualities should a good bearing material have? (5 points) - Answers Softer than the shaft material,
low coefficient of friction, wear-resistant, a good heat conductor and remain relatively stable with heat
changes, readily available.
List Metals generally used in bearing liners and their applications. (5 points) - Answers Babbitt - for
general use
Brass (copper zinc alloy) - for higher speeds and heavier load than babbit
, Bronze (coper tin alloy) - for higher speeds and heavier loading than babbitt
Aluminum - hydraulic pumps
Sintered Bronze - Porous bronze with a built in oil supply. 2:1 ratio.
What characteristics of nylon polyurethanes and phenol laminates affect their applications? - Answers
Heat, , water saturation.
What is the hardest and toughest babbitt made from? - Answers Tin (90%)
How does overheating affect babitt? - Answers Service life is greatly reduced
How is babbitt held in bearing casting? - Answers Holes or slots.
Describe the procedure for pouring a babbitt bearing using a mandrel. (6 Steps) - Answers 1. Gather
Equipment ( oxyacetylene torch putt pliers, babbitt)
2. Fit the torch with a large tip and melt out the remaining babbitt in the casting
3.Smoke the shaft with a straight acetylene flame.
4.Put a putty dam around the shaft and bearing
5. Hold the babbitt with the pair of pliers
6. Melt it into the bearing with the torch.
What must be checked when fitting a bearing? (4 points) - Answers surface finish area of contact,
running clearance, lubrication entry, and grooves
Describe the purpose of tinning. - Answers To secure a thin skin of babbitt to a metallic backing.
Describe the tools used to fit a friction bearing. - Answers Scraper, files, groove chisels.
Describe procedure for fitting a bearing. - Answers 1. Chamfer the top edges or cut an oil groove
2. check bearing for contact by coating mandrel in bluing and rotating mandrel
3. Shave down high spots indicated by bluing
Describe the procedure fro shimming a bearing to the correct amount of clearance. - Answers Insert
shims, make sure they do not make contact with the shaft or the chamfer. Tighten bolts to specs and
rotate the shaft. Add shims or realign the cap.
Describe the procedure for checking bearing clearance with a dial indicator, Pastigage and lead wire. (3
points) - Answers 1. Place indicator on both ends of the shaft and adjust to acquire an even reading.
2. Insert plastigage and tight cap to proper torque and measure width to determine clearance.
