I.S. specifies following total number of grades of tolerances
18
16
20
22
Correct Answer :
A. 18
Related Questions
The helix angle for double helical gears may be made up to
45°
60°
75°
90°
The notch sensitivity q is expressed in terms of fatigue stress concentration factor Kf and theoretical stress concentration factor Kt as
(Kf + 1)/ (Kt + 1)
(Kf - 1)/ (Kt - 1)
(Kt + 1)/ (Kf + 1)
(Kt - 1)/ (Kf - 1)
In helical gears, the right hand helixes on one gear will mesh __________ helixes on the other gear.
Right hand
Left hand
Both A and B
None of these
Allen bolts are
Self locking bolts
Designed for shock load
Used in aircraft application
Provided with hexagonal depression in head
In replacing the V-belts, a complete set of new belts is used instead of replacing a single damaged belt because
Belts are available in sets
Only one belt cannot be fitted with other used belts
The new belt will carry more than its share and result in short life
New and old belts will cause vibrations
The property of a material which enables it to resist fracture due to high impact loads is known as
Elasticity
Endurance
Strength
Toughness
In nitrated parts, the origins of the fatigue cracks will occur at
Surface
Just below the surface
Within the core
None of the above
The strap end of a connecting rod of steam engine is joined by
Gib of cotter joint
Sleeve and cotter joint
Spigot socket cotter joint
Knuckle joint
The piston pin bearings in heavy duty diesel engines are
Needle roller bearings
Tapered roller bearings
Spherical roller bearings
Cylindrical roller bearings
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
Crushing resistance required to crush the rivet per pitch length is
p.d.σc
p.t.σc
n.d.t.σc
(p - d) t.σc
A leaf spring in automobiles is used
To apply forces
To measure forces
To absorb shocks
To store strain energy
The ultimate strength of steel in tension in comparison to shear is in the ratio of
1 : 1
2 : 1
3 : 2
2 : 3
In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where μ = Coefficient of friction between the blocks and the drum, θ = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)
T₁/T₂ = μθ × n
T₁/T₂ = (μθ)n
T₁/T₂ = [(1 - μ tanθ)/ (1 + μ tanθ)]n
T₁/T₂ = [(1 + μ tanθ)/ (1 - μ tanθ)]n
According to I.B.R., when the thickness of the boiler shell (t) is less than 8 mm, then the diameter of the rivet hole (d) is obtained by
Equating tearing resistance of the plate to the shearing resistance of the rivets
Equating tearing resistance of the plate to the crushing resistance of the rivets
Equating shearing resistance to the crushing resistance of the rivets
None of the above
In a boundary lubricated bearing, there is a __________ of lubricant between the journal and the bearing.
Thick film
Thin film
Either A or B
None of these
When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be
4F/ πd²
6F/ πd²
8F/ πd²
16F/ 3πd²
Rankine Gordon formula for buckling is valid for
Long column
Short column
Short and long column
Very long column
The rivet head used for boiler plate riveting is usually
Pan Head
Snap head
Counter sunk head
Conical head
The shear plane in case of bolts should
Be across threaded portion of shank
Be parallel to axis of bolt
Be normal to threaded portion of shank
Never be across the threaded portion
If P1 and P2 are the tight and slack side tensions in the belt, then the initial tension Pi (neglecting centrifugal tension) will be equal to
P1 - P2
P1 + P2
2 × (P1 + P2)
[2 × (P1 + P2)] + Pc Where Pc is centrifugal tension
In a journal bearing, the load on the bearing is __________ to the axis of the journal.
Parallel
Perpendicular
Both A and B
None of these
In most machine members, the damping capacity of the material should be
Low
Zero
High
Could be anything
Stress concentration in static loading is more serious in
Ductile materials
Brittle materials
Equally serious in both cases
Depends on other factors
Which is correct statement? Stress concentration in cyclic loading is
Very serious in brittle materials and less serious in ductile materials
Very serious in ductile materials and less serious in brittle materials
Equally serious in both types of materials
Seriousness would depend on other factors
Turn buckle has
Right hand threads on bout ends
Left hand threads on both ends
Left hand threads on one end and right hand threads on other end
No threads
Machine screws are
Similar to small size tap bolts except that a greater variety of shapes of heads are available
Slotted for a screw driver and generally used with a nut
Used to prevent relative motion between two parts
Similar to stud
The material generally used for aircraft components is
Mild steel
High speed steel
Stainless steel
Aluminium
According to Indian standards, the diameter of rivet hole is made larger than the basic size of rivet by
0.5 mm upto rivet diameter of 24 mm
1 mm for rivet diameter from 27 mm to 36 mm
2 mm for rivet diameter from 39 mm to 48 mm
All of the above
A machine part subjected to __________ is called a strut.
An axial compressive force
A tangential force
An axial tensile force
Any one of these