Question:
An engineering student is fabricating a setup and needs a key for connecting a shaft to the hub of a rotating machine element. The student uses a sunk key which is tapered and prevents relative axial motion.
Which ONE of the following keys did the student most likely use?
An engineering student is fabricating a setup and needs a key for connecting a shaft to the hub of a rotating machine element. The student uses a sunk key which is tapered and prevents relative axial motion.
Which ONE of the following keys did the student most likely use?
Which ONE of the following keys did the student most likely use?
Show Hint
Sunk keys are cut into both shaft and hub; only the tapered ones resist axial sliding.
Updated On: Aug 3, 2026
- Saddle key
- Woodruff key
- Feather key
- Gib-head key
Show Solution
Verified By Collegedunia
The Correct Option is D
Solution and Explanation
Step 1: Understanding the Question:
We need a key that is a sunk key (fits into a keyway cut into both the shaft and the hub), is tapered, and stops the hub from sliding along the shaft.
Step 2: Check option (A), Saddle key:
A saddle key sits in a keyway cut only in the hub and just rests on the curved shaft surface, it is not a sunk key, and it holds on by friction alone, so this does not fit the description.
Step 3: Check option (B), Woodruff key:
A woodruff key is a sunk key shaped like a half-disc, it self-aligns well in tapered shaft applications, but it is not described as a tapered wedge-style key that locks out axial motion the way the question asks, so this does not fit.
Step 4: Check option (C), Feather key:
A feather key is a sunk key with a uniform, parallel cross-section, it is made on purpose to let the hub slide along the shaft while still transmitting torque, so it is the opposite of what is needed here, so this is wrong.
Step 5: Check option (D), Gib-head key:
A gib-head key is a rectangular sunk key with a taper (commonly 1 in 100) along its top face and a raised head for easy removal.
When it is driven into the keyway, the taper wedges tightly between shaft and hub, and this wedge action is what stops any relative axial sliding, matching the question exactly.
\[ \text{Sunk} + \text{Tapered} + \text{No axial motion} = \text{Gib-head key} \]
Final Answer:
Only the gib-head key is sunk, tapered, and built to prevent axial motion. \[ \boxed{\text{Gib-head key}} \]
We need a key that is a sunk key (fits into a keyway cut into both the shaft and the hub), is tapered, and stops the hub from sliding along the shaft.
Step 2: Check option (A), Saddle key:
A saddle key sits in a keyway cut only in the hub and just rests on the curved shaft surface, it is not a sunk key, and it holds on by friction alone, so this does not fit the description.
Step 3: Check option (B), Woodruff key:
A woodruff key is a sunk key shaped like a half-disc, it self-aligns well in tapered shaft applications, but it is not described as a tapered wedge-style key that locks out axial motion the way the question asks, so this does not fit.
Step 4: Check option (C), Feather key:
A feather key is a sunk key with a uniform, parallel cross-section, it is made on purpose to let the hub slide along the shaft while still transmitting torque, so it is the opposite of what is needed here, so this is wrong.
Step 5: Check option (D), Gib-head key:
A gib-head key is a rectangular sunk key with a taper (commonly 1 in 100) along its top face and a raised head for easy removal.
When it is driven into the keyway, the taper wedges tightly between shaft and hub, and this wedge action is what stops any relative axial sliding, matching the question exactly.
\[ \text{Sunk} + \text{Tapered} + \text{No axial motion} = \text{Gib-head key} \]
Final Answer:
Only the gib-head key is sunk, tapered, and built to prevent axial motion. \[ \boxed{\text{Gib-head key}} \]
Was this answer helpful?
0
0
Top GATE PI Design of Machine Elements Questions
Top GATE PI Questions
- In an air-standard Otto cycle, the pressure and temperature of air just before the compression stroke are 200 kPa and 26.85 °C, respectively. The combustion process is assumed to be a constant volume process, where 1.02 MJ/kg heat is added. The cycle efficiency is 50%. The adiabatic index \(γ\) and specific heat at constant volume \(C_v\) can be considered to be constant during the process (corresponding values taken at the mean cycle temperature).
Assuming that the ideal gas law is applicable, \(γ = \frac 43\) and \(c_v= 0.85\ kJ/kg-K\), the maximum pressure (in MPa) reached during the cycle is _____ . (Rounded off to 1 decimal place) - A metallic cylindrical pressure vessel, used to store compressed air in a plant, has 1 m mean radius and 4 mm wall thickness. The maximum allowable normal and shear stresses in the cylindrical portion of the vessel are 100 MPa and 40 MPa, respectively. Considering only these data in the design, the maximum allowable internal gauge pressure (in MPa) of the compressed air is ______ . (Rounded off to 2 decimal places)
- A flat belt drive with pulley of r = 20 cm radius is designed to transmit 6.283 kW power at 600 RPM. In the figure, τ is the corresponding torque. If the coefficient of static friction between the belt and the pulley is 0.3, then the minimum value of the tightening force F (in kN) required to prevent the belt slip is _____ . (Rounded off 2 decimal places)
- Mild steel plates are welded to make butt joints by arc welding with 85% heat transfer efficiency ignoring other losses. The first weld joint is made by selecting arc voltage of 30 V and current of 180 A with a welding speed of 6 mm/s. Using identical plates, a second weld joint is made with the same arc voltage and a welding speed of 8 mm/s. If both the welds have the same heat input, then the welding current (in A) for the second weld joint is _____. (Answer in integer)
- In a single pass cold rolling operation, a flat plate is reduced to a thickness of 3 mm. In this operation, two rolls of diameter 400 mm each are rotating in opposite direction at 300 RPM, and the elastic deflection of these rolls is negligible. The angle of bite is 10°. If the neutral point is present at an angle of 7° from the exit side, then the thickness of the plate (in mm) at the neutral point is _____ . (Rounded off to 1 decimal place)
View More Questions