Shafts and Attachments Flashcards
What type of material is typical key-stock made from?
Low to medium carbon steel. Usually cold drawn.
What does AISI stand for and what do they do?
American Iron and Steel Institute. They set standards for steel manufacture.
What are the most common type of parallel keys?
Square and Rectangular.
Square keys are recommended up to what shaft size?
6 1/2 inches. For anything larger rectangular keys are recommended.
When would you use an Offset or Stepped key?
When a shaft keyway has a different width than the hub keyway.
What type of key requires no keyseat?
Saddle Key.
What types of keys have both ends rounded?
- boxed key
- buried key
- Pratt and Whitney
What are Sunk keys?
They are used when access is restricted and they are set deeper into the shaft.
What are Feather keys?
They permit end movement of two parts either in operation or assembly.
What are the two types of Feather keys?
Fixed and Sliding.
What are the two types of Tapered keys?
Plain and Gib-Headed.
What is the taper on a Tapered key?
1/8” per foot or 1 : 96 ratio.
Keyseats cut at the end of a shaft are called _________.
Open Keyseat.
Keyseats cut into the middle of a shaft are called __________.
Boxed Keyseat.
What type of keyseat does an end mill produce?
Profile Keyseat.
What type of keyseat does a horizontal milling cutter produce?
Sled Runner or Runout Keyseat.
How is the proper depth of a keyseat in a shaft measured?
From the bottom of the keyseat to the opposite side of the shaft.
What are the 3 fits that a key has in relation to the shaft and hub?
Class 1 - Clearance fit.
Class 2 - Relatively tight fit.
Class 3 - Interference fit.
What should be done with a key before driving it into the keyseat to prevent damage or seizing?
Lightly lubricate with oil or an anti-seize agent.
How would you decide what size set screw to use for a key?
The set screw should be 75% of the width of the key.
What are the six types of set screws?
-cup, flat, cone, oval, half-dog, full-dog
Are set screws considered a compression fastener?
Yes.
What would be used to lock set a set screw in place in high vibration areas?
Socket Locking Screw.
Wherever possible, what tool would you use to remove a gib-headed key?
Fox Wedge.
What is a Shaft?
The component of all mechanical devices that transmits motion and power.
What is an Axle?
Rotating device on which a wheel is mounted.
What is a Spindle?
A slender pin or rod which turns, or on which something else turns.
What is a Journal?
The part of the spindle, shaft or axle that rotates in or on a bearing.
When is alloy shafting used?
When wear and corrosion are involved.
When is hollow shafting used?
When weight is an issue.
What is the best way to identify shafting materials?
The numbers stamped into the steel.
What is the definition of stress?
The internal resistance offered by a unit area of a material to an externally applied load.
What stress tends to stretch or lengthen a shaft?
Tensile Stress.
What stress tends to compress or shorten a shaft?
Compressive Stress.
What is Bending stress?
A combination of Tensile and Compressive stress.
What is Shear stress?
When the applied force tends to cut through the shaft.
What is Torsional shear stress?
When torque is applied it causes torsional deformation along the length of the shaft.
What is Fatigue Strength?
The ability of a shaft to resist fatigue.
What is Fatigue loading?
When the shaft is subject to many cycles of loading.
Which type of keyseat has the least stress concentration factor?
Runout.
When placing a bearing what consideration should be taken?
The bearing should be placed as close to the loaded component as possible.
Should the fillet radius on the shaft be smaller or larger than the inner ring radius of the bearing to be mounted?
Smaller.
What should be utilized when using a puller on the end of a shaft?
Shaft Center Protector.
What is Runout?
Any deviation from true.
What is Radial Runout?
Shaft deflection.
What is Circular Runout?
Imperfections on the outside surface.
What is Axial Runout?
Movement of the shaft perpendicular to the shafts axis.
What is a Coupling?
Couplings are use to join two ends of a shaft together.
Name the two types of couplings?
Rigid and Flexible.
What does a Straight Pin, Tapered Pin and Spring Pin all have in common?
They are all interference fit.
What does Positive Allowance refer to?
Minimum allowance between parts.
What does Negative Allowance refer to?
Maximum clearance.
What are the 5 classes of fit?
- running and sliding clearance fit
- locational clearance fit
- transition fit
- locational interference fit
- force or shrink fit
What is tolerance?
It is the maximum and minimum limits of size.
What is the basic hole system?
In this system the design size of the hole is the basic size. (change the shaft size)
What is the basic shaft system?
In this system the design size of the shaft is the basic size. (change the bore)
What is Unilateral Tolerance?
Tolerance for the drawing dimension is applied in one direction only.
What is Bilateral Tolerance?
Tolerance for the drawing dimension is applied in both directions.
What unit of measurement is used when measuring shafts?
1/16 of an inch.
What does µm mean?
Millionth of a meter.
What does µin mean?
Millionth of an inch.
What is the meaning of Fit?
The range of tightness or looseness between mating parts.
What is the recommended width of a key relative to the shaft diameter?
Approximately 1/4 the width of the shaft.
What should remain between a tapered gib head and a hub?
A gap for extraction purposes.
What do Splines allow for between the component and the shaft?
High torque transfer.
Which way do you rotate the eccentric locking collar before tightening the set screws?
In the direction of shaft rotation.
What is the recommended maximum distance between bearings on a standard line shaft?
8 feet.
What is the purpose of a floating bearing on a line shaft?
To accommodate for shaft expansion.
Where should the fixed bearing be placed on a line shaft?
Close to the main drive sprocket, pulley or gear.
How do you minimize bending stress?
Keep loads close to bearings.
What is added to steel to improve machinability?
Lead.
What is the taper on a Tapered Dowel Pin?
1/4 inch per foot or a 1 : 48 ratio.
