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
D. T₁/T₂ = [(1 + μ tanθ)/ (1 - μ tanθ)]n
1/2
1/3
1/4
2/3
Knife edge follower
Flat faced follower
Spherical faced follower
Roller follower
Axial load plus stress due to bending
Acceleration/retardation of masses plus stress due to bending
Axial load plus stress due to acceleration/retardation
Bending plus stress due to acceleration/retardation
Both ends hinged
Both ends fixed
One end fixed and the other end hinged
One end fixed and the other end free
30°
45°
60°
80°
0.5 times
Equal to
2 times
Double
Butt joint with single cover plate
Butt joint with double cover plate
Lap joint with one ring overlapping the other
Any one of the above
Increasing the length of bar
Decreasing the cross-sectional area of the bar
Decreasing the modulus of elasticity of the bar
All of the above
5°
8°
15°
25°
Fine threads
Course threads
Coefficient of friction is greater than tangent of load angle
Hole for inserting split pin
Measure forces
Apply forces
Store energy
All of these
Always in single shear
Always in double shear
Either in single shear or double shear
Any one of these
Constant period
Fixed period
Dwell period
Idle period
Square
Acme
Buttress
BSW
Effective length of column to least radius of gyration of the column
Width of column to depth of column
Maximum size of column to minimum size of column
Effective length of column to width of column
0.5 times
Equal to
2 times
Double
Foundation purposes
Absorbing shock and vibrations
Transmission of power
Lifting and transportation of machines and cubicles
40°
122°
136°
152°
2d
3d
4d
5d
The efficiency of a self locking screw can not be more than 50%
The efficiency of Acme (trapezoidal) thread is less than that of a square thread
If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%
(A) and (B) Only
Spindles of bench vices
Railway carriage couplings
Feed mechanism of machine tools
Screw cutting lathes
One smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
A slot is cut partly in middle of nut and then slot reduced by tightening a screw
A hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip
Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter spitted and bent in reverse direction at other end
Direct tensile stress
Direct compressive stress
Direct bending stress
Direct shear stress
One-fourth
One-third
One-half
Double
A member made of steel will generally be more rigid than a member of equal load carrying ability made of cast iron
A member made of cast iron will generally be more rigid than a member of equal load carrying ability made of steel
Both will be equally rigid
Which one is rigid will depend on several other factors
Bondability
Embeddability
Comformability
Fatigue strength
40
50
70
100
Increase shank diameter
Increase its length
Drill an axial hole through head up to threaded portion so that shank area is equal to root area of thread
Tighten die bolt properly
Electroplating
Polishing
Coating
Shot peening
1
2
3
4