Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Millwright Block 2 (harmonized) NS > Keys And Keyseats > Flashcards

Keys And Keyseats Flashcards

1
Q

Why is the fit of shafts and their attachments imported to the machine?

A

The fit is crucial to smooth running and long life of the machine
Poor fit = poor life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are Keys and keyseats (keyways) used for? (2)

A

To locate parts precisely
To positively join parts together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A __________ is an axial (longitudinal) groove accurately cut (machined) into the shaft or hub to retain a key

A

Keyseat (keyway)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What dictates the key choice?

A

-shaft size
-hub diameter
-mounting style
- torque exerted
-type of material
-intended use
-life of installation (permanent or semi)
-engineering specs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is typical key stock material?

A

Low to medium carbon steel
Ex: 1020

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does AISI stand for?

A

American iron and steel institute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the difference of using cold finished square bar stock such as 1018 vs typical key stock 1020?

A

Square bar stock is made to a minus tolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe parallel keys

A

The top and bottom are parallel
The sides are parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the significance to key stock tolerances

A

Manufactured to a plus tolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the most common form of parallel keys?

A

Square or flat (rectangular) keys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What shafts can square and rectangular keys be used on?

A

All sized shafts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When would you use square keys instead of rectangular keys?

A

When the shaft diameter is up to or under 165mm (6 1/2 inches)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

If a shaft diameter is 190.5mm (7.5 inches) would you use square or rectangular keys?

A

Rectangular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If your shaft keyseat is a different width than your hub keyseat what key would you use?

A

Step key (offset key)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe a saddle key

A

Shaped to fit the curve of the shaft but fitted to sit in the keyseat of the hub

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

If a key is square or rectangular that has both sides rounded what is it called?

A

Boxed or blind key

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What key is this?

A

Box or blinded key

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What key is shown in the picture?

A

Stepped or offset key

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When is a sunk key used?

A

Where the mating machine components restrict access to the key on both sides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the significance to a feather key?

A

Permits movement of two parts either in operation or during assembly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the two types of feather keys?

A

Fixed feather key
Sliding feather key

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe a gib headed key

A

A key with an enlarged head on one end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the purpose of a gib headed key?

A

Allows for quick extraction for parts that are removed frequently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What type of key is this?

A

Gib headed key

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the standard taper for tapered keys?
1 in 96 1/8” in 12” Metric is 1 in 100
26
What is a woodruff key?
A semi circular key but is also available with a flattened bottom
27
At what size are woodruff keys available with a flattened bottom?
1 1/2 inch
28
With woodruff keys which way does the semi circular sit?
Towards the shaft
29
What are the two ways a parallel keyseat may be cut?
Open Boxed
30
If a keyseat is at the end of the shaft is is considered ____________
Open
31
If a keyseat is anywhere along the shaft it is considered to be _____________
Boxed
32
How is the shape of the end of the keyseat determined?
By the type of milling cutter used to cut the groove
33
A horizontal milling cutter produce what type of keyseat end?
Runout or sled runner
34
What type of keyseat end does an end mill produce?
Profile keyseat (straight)
35
What is the maximum tolerance for cutting an offset alignment keyseat?
0.25mm (0.010”)
36
What is the maximum tolerance for cutting an angular misalignment keyseat in a distance of 100mm (4”)
0.10mm (0.002”)
37
Is a set screw required to secure a woodruff key?
No
38
When is the location of the keyseat critical?
When strength or timing of the attachment is important
39
How deep are parallel keyseats cut in the bore?
Deep enough to accommodate 1/2 the height of the key plus clearance
40
When is a tapered keyseat used?
When using a tapered key
41
When should a tapered keyseat be longer than the key?
When the keyseat is NOT located at the end of the shaft
42
Who sets the standards for keys and their keyseats in relation to nominal shaft diameter?
ANSI (American National Steel Institute)
43
What portable device is used to cut keyseats in the field?
Portable keyseat cutter
44
When picking your end mill to produce a keyseat to the correct dimensions you should __________________________
Cut first with the next smallest size end mill
45
How much material should you leave in a keyseat for finishing?
0.25mm (0.010”)
46
What is the size difference between teeth of a broach?
0.07mm (0.003”)
47
Each pass of a broach cuts to a depth of _________
1/16”
48
How do you adjust the depth of a cut with a broach?
By using shims
49
The degree of interference or clearance that a key has in relation to that shaft and hub is recognized as what?
The class of fit
50
How many classes of fit are there in terms of clearance of interference of a key?
3
51
What is the characteristics of a class 1 fit key?
Clearance fit Relatively free fitting
52
How do you obtain a class 1 key fit with a parallel key?
Standard square bar stock and key seat tolerance
53
How do you obtain a class 2 key fit with a parallel key?
Key stock and Standard keyseat tolerances
54
What is a class 2 key seat fit described as?
Relatively tight fit with slight interference
55
How do you obtain a class 3 key fit with a parallel key?
Key stock and precision cut keyseats
56
How would you describe a class 3 key fit?
Interference fit (no relative movement)
57
What are the two main methods to secure a key to the keyseat?
Adhesive Set screws
58
When should adhesives NOT be used to adhere a key to a keyseat?
When temperatures are above 93 Celsius
59
What are the 6 types of set screw points?
Cup Flat Cone Oval Half dog Full dog
60
What is the benefit of using a cup point set screw?
Sharp edges dig into the metal of the shaft giving a very effective locking action
61
Where should a cup point set screw be used?
Where vibration is a concern and shaft marring isn’t an issue
62
What is the disadvantage of using a cup point set screw
It marks up the shaft
63
When are flat point set screws used?
When the shafts needs to remain not damaged at the screw point
64
What is the benefit of using a cone point set screw?
Similar to the cup but more precise
65
When are oval point set screws used?
When the part needs to be adjusted frequently
66
What is unique about the half dog point set screw?
Allows lengthwise movement but prevents rotational movement
67
How does the half dog set screw work?
Engages directly in slots milled longitudinally in a shaft to allow specific movement
68
What can help ensure the maximum thrust is exerted on the shaft from a set screw?
Lubrication
69
If you are adding more than one set screw where should you place them?
90 degrees to each other
70
How can a set screw be locked in place?
Using a socket locking screw
71
When should set screws be replaced? (3)
Major overhauls Signs of wear Every time if stainless steel
72
How do you remove a gib headed key?
Fox wedge(s)
73
What are the 4 methods to removing a parallel key?
Slide hammer Vice grips Key drift Welding a rod to pull it out
74
What is the rule of thumb for finding the width of a key?
1/4 the diameter of the shaft
75
What is the rule of thumb for finding the diameter of a key?
Equal to the shaft diameter
76
What is the rule of thumb for finding the woodruff key sizes?
WD40
77
What is the size of a #406 woodruff key?
WD 40 4/32 06/8
78
Where are woodruff keys typically used?
Tapered shafts Light duty work
79
How much of the height of a sunk key is in the keyseat (shaft)
2/3 of the key
80
How much of the height of a sunk key is in the keyway (bore)
1/3
81
When cutting your tapered keyseat where is it cut?
On the hub side
82
Where is the keyseat cut at an angle for tapered keys?
Hub
83
What type of setscrew has the best grip and tends to stay tight?
Cup point
84
Why do we chamfer all edges of parallel keys?
To clear the radius of the keyseat corners
85
What is the taper on an inch dimension tapered key?
1/8” per foot
86
Where are square keys used?
Most applications on shafts under 6.5”
87
What thickness key would you use on a 2” shaft under heavy load?
1/2”
88
When should a fixed feather key be used?
When you need to lock rotation but move axially
89
What type of keyseat can you cut with an end mill?
Profile key
90
What are splines?
External grooves and lands that manufacturers machine on a shaft to match with internal grooves and lands in a gear, collar, sleeve, or coupling
91
Where should you NOT use tapered gib head keys?
With cast iron hubs
92
What do taper pins require?
Tapered reamer
93
When are pin hubs normally drilled?
On assembly
94
What part of a dimension is the total permissible variation in its size?
Tolerance
95
To reduce stress turned down sections of a shaft should have what 2 things?
No more than 1.5:1 ratio Large as possible fillet
96
What causes fatigue failure?
Repeated stress has work hardened it
97
Where would you measure axial runout?
The face of the attachment or hub
98
What is a class 1 key fitting?
Clearance fit
99
What is a class 2 key fitting
Tight fit
100
What is a class 3 fit?
Interference
101
What is a positive allowance?
Clearance fit
102
What is a negative allowance?
Interference fit
103
Where are rectangular keys used?
Large, hollow shafts, or thin diameter hubs
104
What would you do if a broach did NOT cut a keyway to full depth?
Use a shim under the broach
105
What sort of keyseat is cut with a horizontal mill and a side milling cutter?
Sled runner keyseat

Millwright Block 2 (harmonized) NS (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions