Shafts And Attachments

Question 1

The term “FIT” can be defined as what?

Answer 1

The range of permissible tightness or looseness between two mating parts.

Question 2

What are Kennedy Keys?

Answer 2

A pair of tapered keys installed 90 degrees apart from eachother on a shaft.

Question 3

What is the standard taper for a key in inches?

Answer 3

• 1/96”
• Sometimes expressed as 1/8” in 12”

Question 4

With a hollow shaft, a 25% reduction in weight reduces strength by how much?

Answer 4

6.25%

Question 5

A key is a timing device that is designed to be what on a shaft?

Answer 5

The weakest part of a machine.

Question 6

What is a Class 1 fit for a key on a shaft?

Answer 6

• A clearance fit, where there is a relatively free fit for the key to slide in the key seat.

Question 7

What is a Class 2 fit for keys on a shaft?

Answer 7

Class 2 is a relatively tight fit, with a possible slight interference with the key seat.

Question 8

What is a Class 3 fit for a key on a shaft?

Answer 8

Class 3 is a interference fit for permanent assemblies.

Question 9

Most couplers are positively located on a rotating shaft by means of what?

Answer 9

Keys

Question 10

Tolerence is defined as what?

Answer 10

The total permissble variation a given piece can be both over and undersized.

Question 11

Which is more common, straight keys or taper keys?

Answer 11

Straight

Question 12

What type of key is this?

What is the round part designed for?

Answer 12

• Woodruff Key
• The circular shape permits the key to allgin itself to suit either a parallel or a tapered shaft. The design minimizes any tendency of the key to tip when load is applied.

Question 13

What is the taper ratio for a metric taper key?

Answer 13

1/100

Question 14

Are set screws required with taper keys?

Answer 14

No

Question 15

What is the carbon content of steel AISI 4340?

Answer 15

• 0.40%

Question 16

What is a Dutchman?

Answer 16

A spacer for between a key and Drift Key when removing the key.

Question 17

The Coefficient of Linear Expansion for Steel is what?

Answer 17

0.0000063” per inch per degree of F

Question 18

Is Bar Stock made to oversized tolerence?

Answer 18

No

Question 19

C type hubs have how many bosses?

Answer 19

Two Bosses

Question 20

What is a Saddle Key?

Answer 20

An emergency key.

Question 21

Lead improves what in steel?

Answer 21

Machinability

Question 22

Is Key Stock made to an oversized tolerence?

Answer 22

Yes

Question 23

Ferrous metal keys are made from what?

Answer 23

Cold worked steel.

Question 24

Rectangular Key is also refered to as what?

Answer 24

Flat Key

Question 25

What key should you not use with Cast Iron?

Answer 25

Taper Key. The Cast Iron could crack due to pressure.

Question 26

A key identified as 1212 is what?

Answer 26

- Half-moonshape with a diameter of 1.5” - Related to Woodruff Keys

Question 27

What is the maximum allowance for fitted keys in unidirectional, low torque applications?

Answer 27

0.002” on the sides and 0.005” on the top.

Question 28

What is the rule of thumb for sizing the width of a key for a given shaft?

Answer 28

- 1/4” per inch of shaft diameter.

Question 29

What is a Gib-headed Key?

Answer 29

A rectangular key with an enlarged head on one end to facilitate quick extraction for frequent removal.

Question 30

Which Key is secured with screws in the key?

Answer 30

Fixed Feather Keys

Question 31

True or False: All shafting is usually manufactured in standard dimensions.

Answer 31

True

Question 32

What is a Pratt-Whitney Key

Answer 32

A rounded end, drop in key.

Question 33

When relative motion in the axial direction is required what key is best?

Answer 33

Feather Key

Question 34

What are Keys typically made of?

Answer 34

Steel AISI 1020 in cold drawn condition

Question 35

What are Offset Keys?

Answer 35

Keys with steps in them. They facilitate quick removal.

Question 36

Name two types of Boxed Keys.

Answer 36

- Pratt and Whitney Key - Buried Key

Question 37

What are the two types of Feather Keys?

Answer 37

Fixed and Sliding

Question 38

What is so special about Feather Keys?

Answer 38

They permit end movment for two parts either in operation or during assembly.

Question 39

How are Woodruff Keys sized?

Answer 39

They are given in standardized sizes designated by a code. The last two digits give the Nominal diameter in eighths of an inch. The first digit(s) before the last two give the Width of the key in thirty-secondths of an inch.

Question 40

Can you make Woodruff Keys from round stock?

Answer 40

Yes, in emergencies.

Question 41

What is a Boxed Keyseat?

Answer 41

- A channel cut into the shaft for a Key to sit in. - Not to be mixed up with an Open Keyseat which are cut at the end of a shaft.

Question 42

Describe a Sled-Runner Keyseat.

Answer 42

Question 43

Describe a Profile Keyseat.

Answer 43

Question 44

Do Woodruff Keyseats need setscrews?

Answer 44

No, the the shape of the channel will hold the key in place.

Question 45

What do you use to cut Keyseats in an attachment?

Answer 45

Milling Machines or manually: Broach and Arbor press

Question 46

What insures positive contact between Keys and shafts?

Answer 46

Set Screws

Question 47

What are Fox Wedges?

Answer 47

Wedges which are used to remove Gib-headed Keys.

Question 48

Answer

Answer 48

D)

Question 49

Answer

Answer 49

C)