Types of Keys

Machine Design & Industrial Drafting

1. Machine Design & Industrial Drafting (2141907)
Mechanical Department
Sem.: 4
th
D (D2)
Guided By: Pro. Ashish Majithiya
Prepared By: Gohel Sajan P. (160123119010)

2. What is key ?????
 A key is a machine element used to
connect a rotating machine element to
a shaft.
It is always inserted parallel to the
exist of the shaft.
A keyway is a slot in a shaft and hub
of the pulley to accommodate a key.

3. Types of Keys

4. Sunk key
• The sunk key are provided half in the keyway of the shaft and half in the
keyway of the hub .
• The sunk key are of the following types:
1. Rectangular key
2. Square key
3. Parallel key
4. Gib-Head key
5. Feather key
6. Woodruff Key

5. 1. Rectangular Key
• A key is a piece of mild steel inserted between the shaft and hub of the
pulley to connect these together in order to prevent relative motion
between them.
The key has taper 1 in 100 on the top side only.

6. 2. Square Key
• The only difference between a rectangular sunk key and a square sunk
key is that its width and thickness are equal.
i.e , W=t=d/4

7. 3. Parallel key
• The parallel sunk key may be of rectangular or square section uniform in
width and thickness throughout.
• It may be noted that a parallel key is a taperless and is used where the
pulley, gear or other mating piece is required to solid along the shaft.

8. 4. Gib-Head Key
• It is a rectangular sunk key with a head at one end known as Gib-Head
Key.
• It is usually provided to facilitate and removal of key.

9. 5. Feather key
• A key attached to one member of a pair and
which permits relative axial movement is
known as feather key.
• It is a special type of parallel key which
transmits a turning movement and also
permits axial movement.

10. 6. Woodruff Key
• The woodruff key is an easily adjustable key.
• It is piece from a cylindrical disc having
segmental cross-section in front view of figure.
• This key is largely used in machine tool and
automobile construction.

11. Saddle keys
• The saddle key are of the following two types:
• Flat saddle key
• Hollow saddle key
1.Flat saddle key:- A flat saddle key is a taper key which fits in a keyway

in the hub and is flat on the shaft as show in figure.

12. 2. Hollow Saddle Key :- A Hollow
saddle key is a taper key which fits in a
keyway in the hub and the bottom of the
key is shaped to fit the curved surface of the
shaft.
• It is used as a temporary fastening in
fixing and setting cams etc.

13. Tangent Keys
• The tangent key are fitted in a pair at right
angles.
• Each key is to withatand torsion in one
direction only.
• sThey are used in large heavy duty shaft.

14. Round key
• The round keys, are circular in section and fit into holes drilled partly in
the shaft and partly in the hub.
• They have advantage that their keyways may be drilled and reamed after
the mating parts have been assembled.

15. Splines
• Sometimes, keys are made integral with the shaft which fit in the
keyways broached in the hub. Such shafts are known as splined shafts.
• The Splined shaft are used when the forces to be transmitted is large in
proportional to the size of the shaft.

16. Thank You