Engineering Questions with Answers - Multiple Choice Questions
MCQs on Bench Centres
1 - Question
What is the material of the bench center’s base?
a) Copper
b) Wood
c) Cast Iron
d) Steel
View Answer
Answer: c
Explanation: The base of Bench centre is generally made from close-grained cast iron and should be free from any casting defect. Defects may cause error and failure of materials.
2 - Question
Why T- slots are provided on the base of bench centres?
a) To reduce its weight
b) For the attachment of centre holders
c) For the attachment of base to table
d) For easy loading and unloading
View Answer
Answer: b
Explanation: For the attachment of centre holder, T-slots are provided at the base of bench centre. A spring loaded centre is present for easy loading and unloading.
3 - Question
What is the range in which distance between the centres varies?
a) 100 to 200 mm
b) 200 to 400 mm
c) 300 to 400 mm
d) 500 to 1500 mm
View Answer
Answer: d
Explanation: Distance between the centres in centre bench depends upon the centre height and varies between 500 to 1500 mm with centre height accordingly.
4 - Question
Which of the following is incorrect about bench centre’s physical characteristics?
a) Centre holders may be located in any position
b) Box type straight edges have a rigid cross section for minimum deflection
c) Minimum hardness of bench centre’s base is 180 HB
d) Male or female centres are non-adjustable on bench centres
View Answer
Answer: d
Explanation: Along the vees of the centre holders, male or female centres can be adjusted and locked in any desired position.
5 - Question
What will happen due to out-of-straightness of a part?
a) Less finished surface of part
b) No error in roundness
c) Failure of a part
d) Doubling run out effect
View Answer
Answer: d
Explanation: A doubling run out effect and roundness error is caused by out-of-straightness of the part. Run out is also called as out-of true running.
6 - Question
What are the centre heights that available for Bench centres?
a) 125 mm
b) 125, 160 mm
c) 125, 250 and 300 mm
d) 125, 160, 200, 250 and 300 mm
View Answer
Answer: d
Explanation: 125, 160, 200, 250 and 300 mm heights of centres are available in bench centres and according to these heights, centre distance is decided.
7 - Question
Match the following apparatus with the function they perform.
A) Straight Edges 1) Checking Eccentricity B) V-Blocks 2) Checking Flatness C) Bench Centres 3) Small angle measurement D) Spirit Level 4) Checking Roundness
a) A-2, B-4, C-1, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-1, C-4, D-2
d) A-4, B-3, C-2, D-1
View Answer
Answer: a
Explanation: Straight edges are used with surface plates to check straightness and flatness. V-blocks are used to check roundness of cylindrical pieces. Bench centres are used for rotary components to check eccentricity. Spirit levels are used to measure small inclination.
8 - Question
How much deviation is permitted in parallelism of centres axis w.r.t. guideways for 125-160 mm center height?
a) 0.01 mm/200 mm
b) 0.01 mm/300 mm
c) 0.1 mm/300 mm
d) 0.001 mm/300 mm
View Answer
Answer: b
Explanation: This permissible deviation in parallelism is specified by IS: 1980-1978.
9 - Question
Which option is correct for given statements about out of roundness of V blocks?
Statement 1: Shafts can be out-of-roundness due to improper centre alignment.
Statement 2: Adjustable V-Blocks can be used to show out-of-roundness.
a) T, T
b) T, F
c) F, T
d) F, F
View Answer
Answer: a
Explanation: Many factors affects the roundness of shafts like angle of centres, alignment of centres, centre holes, run-out of piece etc. Adjustable V-Blocks can be used to measure correct roundness.