The helix angle for single helical gears ranges from
10° to 15°
15° to 20°
20° to 35°
35° to 50°
Correct Answer :
C. 20° to 35°
Related Questions
The value of stress concentration factor depends upon
Material and geometry of the part
Geometry of the part
Material of the part
None of these
According to maximum shear stress theory, the maximum shear stress in the shaft is
(1/2) × √(σ² + 4τ²)
√(σ² + 4τ²)
(1/2) × [σ + √(σ² + 4τ²)]
σ + √(σ² + 4τ²)
Creep in belt is due to
Material of the belt
Material of the pulley
Uneven extensions and contractions due to varying tension
All of the above
Cold working
Increases the fatigue strength
Decreases the fatigue strength
Has no influence on fatigue strength
Alone has no influence on fatigue strength
When an open coiled helical compression spring is subjected to an axial load (W), the compression produced in the spring will be (where n = No. of active turns of the spring, and G = Modulus of rigidity for the spring material)
2WD3n/Gd⁴
4WD3n/Gd⁴
8WD3n/Gd⁴
16WD3n/Gd⁴
The bending moment M and a torque T is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then M is equal to
T/2
T
2T
4T
Yield point in fatigue loading as compared to static loading is
Same
Higher
Lower
Depends on other factors
The width of the pulley should be __________ width of the belt.
Equal to
Less than
Greater than
None of these
Which of the following screw thread is adopted for power transmission in either direction?
Acme threads
Square threads
Buttress threads
Multiple threads
A bolt of uniform strength can be developed by
Keeping the core diameter of threads equal to the diameter of unthreaded portion of the bolt
Keeping the core diameter smaller than the diameter of the unthreaded portion
Keeping the nominal diameter of threads equal to the diameter of unthreaded portion of the bolt
None of the above
The suitable material for belt in agricultural machinery is
Leather
Rubber
Cotton duck
Balata gum
The permissible stress for carbon steel under static loading is generally taken as
2000-3000 kg/m²
3000-4000 kg/cm²
4000-4500 kg/cm²
7500-10,000 kg/cm²
In static loading, stress concentration is more serious in
Brittle materials
Ductile materials
Brittle as well as ductile materials
Elastic materials
The difference between the tooth space and the tooth thickness as measured on the pitch circle, is called
Working depth
Clearance
Backlash
Face width
According to Indian standard specifications, 100 H6/g5 means that
Tolerance grade for the hole is 6 and for the shaft is 5
Tolerance grade for the shaft is 6 and for the hole is 5
Tolerance grade for the shaft is 4 to 8 and for the hole is 3 to 7
Tolerance grade for the hole is 4 to 8 and for the shaft is 3 to 7
A tapered key which fits in a key way in the hub and the bottom of which is shaped to fit the curved surface of the shaft, is known as,
Hollow saddle key
Hollow key
Soft key
None of these
Gear box is used
To produce torque
For speed reduction
To obtain variable speeds
To increase efficiency of system
Which of the following has threads at both ends?
Bolt
Tap bolt
Stud
None of these
The material used for brake lining should have __________ coefficient of friction.
Low
High
Moderate
None of these
In oilness bearings
The oil film pressure is generated only by the rotation of the journal
The oil film is maintained by supplying oil under pressure
Do not require external supply of lubricant
Grease required to be applied after some intervals
The endurance or fatigue limit is defined as the maximum value of the stress which a polished standard specimen can withstand without failure, for infinite number of cycles, when subjected to
Static load
Dynamic load
Static as well as dynamic load
Completely reversed load
The process extensively used for making bolts and nuts is
Hot piercing
Extrusion
Cold peening
Cold heading
The included angle between the sides of V-belt is
40°
45°
38°
60°
When the connected members are very yielding (soft gasket) as compared to the bolt, then the resultant load on the bolt will be equal to the
Initial tension
External load applied
Sum of the initial tension and external load applied
Initial tension or external load, whichever is greater
Which of the following pipe joints would be suitable for pipes carrying steam?
Flanged
Threaded
Bell and spigot
Expansion
Fabric belts are used in industrial applications because
They are cheap
They can work at high temperature
They are unaffected by moisture and humidity
None of the above
The stretching in a belt can be controlled by __________ the stress in the belt.
Reducing
Increasing
Both A and B
None of these
The shock absorbing capacity of a bolt may be increased by
Increasing its shank diameter
Decreasing its shank diameter
Tightening the bolt properly
Making the shank diameter equal to core diameter of thread
An alien bolt is
Self locking bolt
Same as stud
Provided with hexagonal depression in head
Used in high speed components
If shearing stress in nut is half the tensile stress in a bolt, then nut length should be equal to
Diameter of bolt
0.75 × diameter of bolt
1.25 × diameter of bolt
1.5 × diameter of bolt