101. Cutting speed in grinding is set to a high value to

1. 1. Reduce the cutting time

   
   
   

   2. Increase the bond strength

   
   
   

   3. Improve cooling of job and wheel

   
   
   

   4. Reduce the wheel wear

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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102. The standard specification of a grinding wheel is A-46-M-6-V-21. It means a wheel of

1. 1. Aluminum oxide of mesh size 6

   
   
   

   2. Boron carbide of mesh size 46

   
   
   

   3. Aluminum oxide of mesh size 46

   
   
   

   4. Silicon carbide of mesh size 6

   
   
   

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1. View Hint View Answer Discuss in Forum

   

   Correct Option: C

   

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103. Two identical cylindrical jobs are turned using
     (a) a round nosed tool of nose radius 2 mm and
     (b) a sharp corner tool having principal cutting
     edge angle = 45° and auxiliary cutting edge angle = 10°. If the operation is carried out of the feed of 0.08 mm/rev, the height at micro irregularities on the machined surfaces (in mm) in the two cases will be

1. 1. 0.0001, 0.024

   
   
   

   2. 0.0002, 0.012

   
   
   

   3. 0.0003, 0.024

   
   
   

   4. 0.0004, 0.012

   
   
   

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1. View Hint View Answer Discuss in Forum

   ASA Signature ψ = 45°, ψ =10°
   

   Hmax =	f²	=	0.08²
   	8R		8 × 8

   
   ORS signature = 0.0004 mm
   

   Hmax =	f	=	0.08
   	tan ψ + cot ψ		tan4548° + cot 10°

   
   Hmax = 0.012 mm

   Correct Option: D

   ASA Signature ψ = 45°, ψ =10°
   

   Hmax =	f²	=	0.08²
   	8R		8 × 8

   
   ORS signature = 0.0004 mm
   

   Hmax =	f	=	0.08
   	tan ψ + cot ψ		tan4548° + cot 10°

   
   Hmax = 0.012 mm

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104. Tool life equations for two tools under consideration are as follows
     HSS: VT^0.2 = 150
     Carbide: VT^0.3 = 250
     Where V is the cutting speed in m/min and T is the tool life in mm. The breakeven cutting speed above which the carbide tool will be beneficial is

1. 1. 54 m/min

   
   
   

   2. 150 m/min

   
   
   

   3. 194 m/min

   
   
   

   4. 250 m/min

   
   
   

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1. View Hint View Answer Discuss in Forum

   HSS:
   VT^0.2 = 150
   VT^0.3 = 250
   

   	150		1/0.2	=		250		1/0.3
   	V					V

   
   V = 54m/ min

   Correct Option: A

   HSS:
   VT^0.2 = 150
   VT^0.3 = 250
   

   	150		1/0.2	=		250		1/0.3
   	V					V

   
   V = 54m/ min

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105. In resistance welding, heat is generated due to the resistance between

1. 1. electrode and workpiece

   
   
   

   2. asperities between touching plates

   
   
   

   3. two dissimilar metals being in contact

   
   
   

   4. interatomic forces

   
   
   

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1. View Hint View Answer Discuss in Forum

   Because of Air Resistance is very high.

   Correct Option: B

   Because of Air Resistance is very high.

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