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48 Cards in this Set
- Front
- Back
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With ISO tolerance codes, what does an upper case letter mean? |
It indicates the tolerance for a hole size |
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Which of the anti friction bearings is type "NA" |
Needle bearing |
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Do integral rubbing seals require mounting? |
They do not require mounting as they are part of the bearing assembly |
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What type of seals use a garter spring? |
Q |
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What does the suffix RS and Z mean? |
RS: rubbing seal Z: non-rubbing seal |
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Another name for carb bearing is? |
Compact aligning roller bearing |
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What is another name for a Conrad bearing? |
Single row deep groove ball bearing |
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With horizontal split pillow blocks, at 55-______degrees stops should be installed at the ends of the base |
55-120 degrees |
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Babbitt May also be referred to as..... |
White metal alloy |
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List two bearing surfaces other than Babbitt |
-Aluminum silicone -aluminum tin |
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Before installing bearings you should inspect the housing for |
-cracks -burs - out of round -taper |
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Split bearings are held tightly to the housing because of these two things |
Crush and spread |
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What is crush? |
How much it protrudes above the bearing shell --> needed for good heat transfer |
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What retaining features are used on a split bearing to keep it from rotating |
Tabs and dowls |
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When inspecting a journal for taper, how Many positions along the shaft should you measure? |
6 |
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How is a housing check done? |
With 0.005 mils shims and lead wire |
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What theory is based on hydrodynamic principals? |
The wedge theory |
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Give two examples of elasto-hydrodamic film lubrication |
-roller bearings -gears |
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What is the contact angle for an angular contact ball bearing? |
30-32 degree contact angle |
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Boundary film forms at low or high speeds? |
Low |
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What are three reasons why we like petroleum based oil |
-it doesn't brake down -cheap -has a good Viscosity |
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What has a higher viscosity index, paraffin based or naptha based oils? |
Paraffin |
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List five things additives are used for |
-extreme pressure -deforming -Demulsifier -detergents -deoxidizing |
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A shaft is always centred in a bearing housing. True or false? |
False |
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Synthetic based oils are the least reactive. True or false? |
False |
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Alight load running at a high speed needs a _______ viscosity |
Low viscosity |
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A bottle lubricator is recommended for below how many surface feet per min? |
250 |
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List three key components of a pressurized lubrication system |
-pump -filter -pressure relief valve -blinds! |
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Oil mist lubrication is recommended for small high speed bearings. True or false? |
True |
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What is the nominal contact load? |
A line drawn through the area of contact at the inner and outer race, not under load |
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Define drop point |
W |
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What are two common thickeners? |
Soap and bentonite |
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What are the functions of a detergent in an oil? |
1) controls acid build up 2) acts as an anti wear 3) acts as a rust inhibitor |
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What is the ability of a bearing to allow abrasive contaminants to become entrapped? |
Embedability |
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What's the ability to retain a film of fluid? |
Wetability |
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The ability to transfer heat to prevent hot spots? |
Conductivity |
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Allows the material to yield to misalignment and imperfections in the shaft? |
Conform ability |
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Resistance to cracking or flaking from rapidly changing loads |
Fatigue resistance |
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What is another name for porous bronze bushing? |
Sintered bronze or oilite |
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How can you pre-charge a pre-lubricated bushing? |
By soaking the bushing in oil 90°C for half an hour |
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What is compressive strength |
The bearing material must be strong enough to support the shaft loads at maximum operating temperature. Resistance decreases as compressive strength increases |
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What is embeddability? |
How well a material will handle contaminants without failing. High embeddability allows abrasive contaminants to become embedded in the material |
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What is deformability? |
Deformability allows the material to you to misalignment or imperfections in the shaft |
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What is wetability |
Ability to retain a film of lubricant |
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What is bondability? |
Bearing materials should form a good metallurgical bond to the backing material |
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What is compatibility |
Must not seize or weld to the journal m under rubbing conditions such as during start up |
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What is false loading |
A small chip or Burr can cause a bearing to support the load on only part of it surface |
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What percentage of oil can sintered bronze hold? |
3-30% |
