Shafts And Attachments Flashcards
What is metalizing used for?
Building up worn sections of shaft
What is the main difference between hot rolled and cold rolled steel?
Surface finish and size tolerance
Which of these statements ave most true about square keys?
Sunk half their height into the shaft
Which is most true about pinned hubs?
Are often drilled on assembly
How would you replace a hub that is pinned with a tapered pin?
Step drill the hub in the drill press and final ream it on assembly
Which would be an advantage of standard parallel keys over tapered pins to locate a hub on a shaft?
Stronger and interchangeable between hubs
What could you do to keep2” diameter shaft from breaking where a 1” bore pulley sheave mount?
Turn section of the shaft down to 1.5” before it meets the 1” journal diameter
What method does not heat parts evenly?
Torch
What is the best tool toget in behind a hub next to a housing to removeit?
Bearing spitter
What is the most important thing to know about saddle keys?
’ Protects the shaft
What would you do if a broach did not cut a keyway full death?
Use a shim under the broach
What is Prussian blue used for?
Identifying contact patterns for fitting and adjusting
Which world be the best way to measure axial runout?
Measure on the face of the attachment or hub
What would you do if a rotor mounted on a face flange measured 0.022” of axial runout?
Try remounting it with attention to cleaning and torque pattern
Twisting forces put what sort of stress on a key?
Shear
What is meant when we say that the base is true?
It is flat and square
What is the best tool for determine radial runout?
Dial Indicator
How can a bend shaft he repaired once the high points are identified
Hydraulic press
Where should the millwright put the bearings on a shaft it he has thechoice?
As close to the loaded components as possible
What is not an advantage of shirk fits on hubs?
Easy to remove
What is a keyway that goes to the end of the shaft call?
Open
What is the thickness of d woodruff key?
5/16
What is the thickness of a keys that would be used on a 2 inch shaft
1/2, every inch = 1/4”
What are keys used for?
To transmit power and motion
Which keyseat is cut at an angle for a tapered key?
Hub
What type of setscrew has the best grip and tends to stay Tight?
Cup point
Why do we chamfer the edges of parallel keys?
To clear radius of the keyseat corners!
How would you check runout on a shaft?
Use an dial indicator while rotating shaft.
What is the taper on an inch dimension tapered key?
1/8 inch foot
What is the greatest danger when straight a shafts in a press?
The shaft rolling or springing away
What does unilateral tolerance mean?
All tolerances for the drawing dimension is applied in one direction only
What does bilateral tolerance mean?
Means that the tolerance for the drawing dimensions is applied both directions
Radial runout?
Occurs when the shaft and the attachments are not concentric in their rotation
Circular runout?
- Occurs because of imperfections ( ovality, bumps, etc) in the cross section of the part
Axial runout?
Occurs because attachment do not rotate perpendicularly to the shaft axis
What is torsional shear stress?
Force applied to the shaft by resistance to turning that is set by the driven parts.
What are the two main stresses?
Bending and torsional shear
Why would you use hollow shafting?
Can reduce weight with a minimum strength reduction
Long centre distance can be spanned with less weight on each bearing.
Can conduct coolant
Can function as an output shaft for shaft- mounted reduction units.
What does line shafting do?
Provides power to or timing to several drives on a single shaft.
The steels ductility and weld ability decrease as _
Its carbon content increases
What does 1020 stand for?
1 indicates the alloy group is carbon
#0 indicates No major alloying element besides carbon
#20 indicates 0.20% carbon content.
What does 4340 mean?
4 indicates that the alloy group is molybdenum
#3 indicates that nickel and chromium are added in specific concentrations
#40 indicates 0.40% carbon content
Numbering system , what do the 4 digits means?
First 2 digits indicate specific alloy groups, the last 2 digits indicate amount of carbon in the steel
What does a clearance fit indicate?
Shaft is always smaller than the bore
What does a transition fit indicate?
Shaft and Bose size are such that the combination of their fits give either an interference fit or a clearance fit
What does an interference fit indicate?
Shaft is larger than bore of machine
What key dosen’t require a keyseat in the shaft?
Saddle key
What keys permit end movement of the two parts either in operation or during assembly?
Feather keys
What is the standard taper for tapered keys?
1 in 96 Or 1/8 in 12 inches. (Metric is 1 in 100)
What is an axle?
Rotating device on which a wheel is mounted
What is a spindle?
Is a slender pin or rod which turns, or on which something else turns,
What is a journal?
Part of the spindle, shaft, or axle that rotates in or on a bearing, plain friction bearing are often referred to as journal bearings
What does hot rolled refer to?
Finishing process in the manufacture of the steel.
Smooth surface finish, manufactured to close tolerances is what shafting ?
Finished shafting
Where wear and corrosion are great is an example of
Alloy shafting
What type of shafting is used for power transmissions?
Hollow shafting
When sections of the shafting must bc turned down for a bearing or other machine components, the reductions in diameter should be no more than?
1.5:1
What does critical speed depend on? (4)
Size of the load or loads carried by the shaft
Length of the shaft
Diameter of the shaft
The kind of support bearings
What is critical speed?
Speed at which rotating shafts tends to vibrate violently in the transverse direction it the shaft rotates in the horizontal direction
What does positive allowance refer to?
Minimum clearance between mating parts
Negative allowance refers to?
Maximum interference
What are the three methods of fitting?
Force fitting
Shrink fitting
Expansion fitting
What is the growth formula?
L X (COEF) x T
