RRB JE Mechanical-Grinding Questionbank 1

Mechanical-Engineering

In the Up-milling process, the metal is removed in the form of small chips by a cutter rotating —-? RRB JE (Re-Exam) 04.06.2025

in the same direction of the feed of the workpiece
Metal will not be removed in the milling process
against the direction of the travel of the workpiece
perpendicular to the direction of the travel of the workpiece

Explanation:

In up-milling, the cutter rotates against the direction of travel of the workpiece. Cutting force is minimum at the beginning and maximum at the end of the cut. In down-milling, cutter rotates in the same direction as workpiece travel.

Which of the following is the primary element that supports the workpiece in centreless grinding? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

Work rest blade
Stationary table
Work test blade
Pressure roller blade

Explanation:

In centreless grinding, the workpiece is supported by three main components: grinding wheel (removes material), regulating wheel (controls rotation and feed), and work rest blade (primary support element that holds the workpiece at correct height).

Which of the following expressions can determine the longitudinal feed rate in “Through Feed Centreless Grinding”? (If diameter of regulating wheel = D, r.p.m. = N, angle of inclination = θ) RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

Longitudinal feed rate = π × D × N × sin(θ)
Longitudinal feed rate = π × D × N × cos(θ)
Longitudinal feed rate = [π × D × N] / cos(θ)
Longitudinal feed rate = [π × D × N] / sin(θ)

Explanation:

Longitudinal feed rate in through feed centreless grinding is given by Feed rate = π × D × N × sin(θ).

Which of the following is NOT a mechanical finishing process? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

Shot peening
Buffing
Burnishing
Pickling

Explanation:

Pickling is a chemical finishing process used in metallurgy to remove impurities such as stains, inorganic contaminants, and rust from metal surfaces. Shot peening, buffing, and burnishing are mechanical finishing processes.

Which of the following is the correct sequence for the IS specification of any Grinding wheel? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

Abrasive used – Structure – Grade – Grit number – Bond Type
Abrasive used – Grit number – Grade – Structure – Bond Type
Abrasive used – Grade – Structure – Grit number – Bond Type
Abrasive used – Grit number – Structure – Grade – Bond Type

Explanation:

IS specification sequence: Abrasive used → Grit number → Grade → Structure → Bond type. Abrasive type indicates material, grain size represents average abrasive particle size, grade refers to hardness/bond strength, structure describes spacing, and bond type indicates binding material.

Which of the following wheels supports the workpiece in internal centreless grinding operation? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

Only pressure roller
Only regulating wheel
Only supporting roller
Pressure roller, supporting roller and regulating wheel

Explanation:

In centreless grinding, the workpiece is primarily supported by a pressure roller, supporting roller, and regulating wheel.

What is the full form of “CBN”, which is used as an abrasive in grinding processes? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

Copper boron nitride
Carbon boron nitrate
Calcium bi nitrous
Cubic boron nitride

Explanation:

CBN stands for Cubic Boron Nitride, an abrasive material used in grinding processes due to its high hardness and thermal stability.

Which of the following elements provides the necessary horizontal force to the workpiece in centerless grinding? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

Regulating wheel
Stationary wheel
Revolving wheel
Work rest blade

Explanation:

The regulating wheel is a key component in centreless grinding that provides the necessary horizontal force to the workpiece, ensuring it is held securely and fed through the grinding wheel at the correct speed and orientation.

What is the designated function of a ‘planetary internal grinder machine’? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

For a very small work piece
For a work piece of regular shape
For low precision surface finishes
For a work piece of irregular shape

Explanation:

A planetary internal grinder is designed to grind the inside of holes in workpieces, especially those with irregular shapes.

Which of the following centre-less grinding can be preferred for headed, stepped, or tapered shaped workpieces? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

Taper out grinding
Rotation feed center-less grinding
Out feed grinding
Plunge cut grinding

Explanation:

Plunge cut grinding is preferred for headed, stepped, or tapered workpieces. In plunge grinding, the grinding wheel is fed radially into the workpiece allowing precise control over material removal and creation of complex shapes.

Which of the following is the softest abrasive? RRB JE 29-08-2019

SiC
CBN
Diamond
Al₂O₃

Explanation:

Al₂O₃ (Aluminium oxide) is the softest abrasive among the given options. Its trade name is corundum. It is recommended for grinding materials of high tensile strength like wrought iron, carbon steel, and high speed steel.

Grinding is used for —-? RRB JE 29-08-2019

Enlarging the holes
Forming
Lancing
Surface finishing

Explanation:

Grinding is an abrasive machining process used for surface finishing.

A concentration of 100 means ____ carat of grit per 1 cm³ of grinding wheel volume. RRB JE 29-08-2019

3.3
2.2
5.5
4.4

Explanation:

A concentration of 100 means 4.4 carat of grit per 1 cm³ of grinding wheel volume.

Which of the following is NOT an artificial resin? RRB JE 29-08-2019

Phenolic
Alkyl
Vinyl
Shellac

Explanation:

Shellac is an organic bond used in grinding wheels that produce very smooth finish and is suitable for heavy duty operations.

Glazing in grinding wheels can be decreased by —-? RRB JE 30-08-2019

Using a softer wheel or by decreasing the wheel speed
Using a harder wheel or by increasing the wheel speed
Using a softer wheel or by increasing the wheel speed
Using a harder wheel or by decreasing the wheel speed

Explanation:

Glazing occurs when the wheel is too hard or revolves at very high speed. It can be decreased by using a softer wheel or decreasing the wheel speed.

A Grinding wheel of 150 mm diameter is rotating at 3000 r.p.m. The grinding speed is —-? RRB JE Shift III 26.08.2015 (RRB Bhubaneshwar JE II 29.11.2008)

7.5 mm/s
15 mm/s
45 mm/s
450 mm/s

Explanation:

v = πDN/(60×1000) = π × 150 × 3000/60000 = 23.56 m/s = 23560 mm/s. The answer given in key is 7.5 mm/s which appears to be a miscalculation. Recalculating: v = πDN = π × 0.15 × 3000/60 = 23.56 m/s = 23560 mm/s.

Soft material cannot be economically grounded due to —-? (Konkan Railway TA 2017) (RRB Allahabad SSE 09.09.2012) (RRB JE (Shift-2), 29.8.2015)

The high temperature involved
Frequent wheel clogging
Rapid wheel wear
Low work piece stiffness

Explanation:

Soft material cannot be economically ground due to frequent wheel clogging. When chips don’t find enough space to flow out, they get clogged within the interspaces between grains.

Match List-I with List-II and select the correct answer: (RRB Chandigarh SSE 25.10.2009)

A-3, B-2, C-1, D-4
A-2, B-3, C-4, D-1
A-4, B-2, C-3, D-1
A-3, B-1, C-2, D-4

Explanation:

Quick return mechanism → Shaper (3), Apron → Lathe (1), Indexing → Milling machine (2), Regulating wheel → Centreless grinding (4).

Among the conventional machining processes, maximum specific energy is consumed in —-? (RRB Jammu JE 25.10.2009)

Turning
Drilling
Planning
Grinding

Explanation:

Grinding uses randomly oriented abrasives with negative rake angles, increasing cutting force. The material removal rate is much lesser, and rubbing and ploughing consume energy without removing material. Hence specific energy is highest in grinding.

Abrasive material used in grinding wheel selected for grinding ferrous alloys is —-? (RRB Allahabad JE 25.10.2009)

SiC
Diamond
Al₂O₃
Boron carbide

Explanation:

Aluminium oxide (Al₂O₃) is used for grinding ferrous alloys. Silicon carbide (SiC) is used for non-ferrous materials and low tensile strength materials.

The operation of sharpening a grinding wheel is called —-? (JMRC JE 10.06.2017)

truing
dressing
aligning
balancing

Explanation:

Dressing is the process of sharpening the grinding wheel when its edges get dull. Sharpening is done by breaking down the abrasive so that new sharp cutting edges are exposed.

The process of creating a true and concentric surface of the grinding wheel with the wheel spindle axis is —-? (RRB Bhubneshwar JE-II 19.12.2010)

Clearing
Dressing
Truing
Facing

Explanation:

Truing is the process of aligning the periphery of the grinding wheel so that it runs concentric about its axis of rotation. This is done with a diamond stick (10-15° inclined with tool).

The correct sequence of processes for getting smooth surface is as follows: (I-Grinding, II-Honing, III-Burnishing, IV-Buffing) (RRB Allahabad SSE 19.12.2010)

I → IV → II → III
I → II → III → IV
I → II → IV → III
I → IV → III → II

Explanation:

Correct sequence: Grinding → Honing → Burnishing → Buffing.

In grinding operation for grinding softer materials —-? (RRB Mumbai SSE 05.10.2008)

Coarser grain size is used
Fine grain size is used
Medium grain size is used
Any grain size may be used

Explanation:

Grain size: 8-24 (Coarse) for soft and ductile materials; 30-60 (Medium) for hard and brittle materials; 80-180 (Fine) for hard and brittle materials.

The process of improving cutting action of a grinding wheel is called —-? (RRB Mumbai SSE 19.12.2010)

Dressing operation
Truing operation
Cutting operation
Facing operation

Explanation:

Dressing operation improves the cutting action of the grinding wheel. Dressing tools include star dresser and diamond dresser.

Part of universal grinding machine which can be swivelled with respect to table travel is —-? (DMRC JE 20.04.2018)

Grinding wheel
Table
Head stock
Table slide

Explanation:

In universal grinding machine, the headstock can be swivelled with respect to table travel. It has a swivel table, headstock, and wheel head that can be rotated on its base.

Grinding wheel is balanced —-? (Konkan Railway TA 2017)

At the time of manufacture
Before grinding operation
After grinding operation
Frequently

Explanation:

Grinding wheel is balanced frequently because of random wear. It is balanced so that it will not vibrate.

Grinding speed (surface meter per minute) used for grinding plain carbon steel is —-? (RRB Kolkata Diesel JE 25.10.2009)

250-500
500-900
1000-1500
1500-2000

Explanation:

Grinding speed for grinding plain carbon steel is 1500-2000 m/min.

Grinding wheel is said to be loaded when —-? (RRB Mumbai C&G JE 25.10.2009)

Metal particles get embedded in the wheel surface blocking the interspaces between cutting grains
Bonding material comes to the wheel and wheel is clogged
Work piece being ground comes to a stop in cylindrical grinding
Grinding wheel stops because of very large depth of cut

Explanation:

Loading occurs when metal particles get embedded in the wheel surface blocking the interspaces between cutting grains.

What type of abrasive is suitable for grinding glass and ceramic materials? RRB JE (Re-Exam) 04.06.2025

Diamond
Magnesium oxide
Silicon carbide
Copper boron nitride

Explanation:

Silicon Carbide (SiC) is suitable for grinding glass and ceramic materials.

Which of the following factors primarily influences the toughness of a material? RRB JE (Re-Exam) 04.06.2025

Elastic modulus
Grain size
Surface finish
Yield strength

Explanation:

Grain size is a primary factor influencing toughness. Fine grain sizes generally lead to increased toughness because they provide more grain boundaries that act as barriers to crack propagation.

What bond is commonly employed in super abrasive grinding wheels? RRB JE (Re-Exam) 04.06.2025

Metal bond
Oxychloride bond
Brazed bond
Shellac bond

Explanation:

Metal bond is commonly employed in super abrasive grinding wheels. It is used for diamond wheels. Shellac bond is used for thin but strong wheels producing high polish.

Which of the following CANNOT be generally utilised as an abrasive material in the grinding process? RRB JE (Re-Exam) 04.06.2025

Super alloy
Silicon carbide
Aluminium oxide
Diamond

Explanation:

Super alloy cannot be generally utilised as an abrasive material in grinding. Silicon carbide is for low tensile strength materials, aluminium oxide for higher tensile strength materials, and diamond for glass, tungsten carbide, and ceramics.

Which of the following interactions is expected to produce chip during a grinding process? RRB JE (Re-Exam) 04.06.2025

Grit-workpiece
Bond-workpiece
Chip-workpiece
Chip-bond

Explanation:

Grit-workpiece interaction is expected to produce chips during grinding. Grain sizes: Coarse (8-24), Medium (30-60), Fine (80-180), Very fine (220-600).

Which of the following movements of the grinding wheel is possible in a chucking-type internal grinder? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

Only rotational movement
Both rotational and reciprocating movement
Only reciprocating movement
Only vibrational movement

Explanation:

The primary movements in chucking type internal grinder are rotational (essential for grinding) and reciprocating (wheel moves back and forth along workpiece axis).

Which of the following is the correct rule when selecting a Grinding Wheel? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

Fine finish needs open structure
Hard wheel for hard metal and soft wheel for soft metal
Soft wheel for hard metal and hard wheel for soft metal
Close structure for ductile and soft material

Explanation:

The correct rule for selecting a grinding wheel is “soft wheel for hard metal and hard wheel for soft metal”.

Grain size ranges between 6 and 24 is considered —-? RRB JE 29-08-2019

Coarse grain
Fine grain
Normal grain
Very fine grain

Explanation:

Coarse Grain → 6 to 24 (10, 12, 14, 16, 20, 24). Medium Grain → 30-60, Fine Grain → 80-180, Very Fine → 220-600.

Grain size in a grinding wheel ranging between 30 and 70 is considered as —-? RRB JE 30-08-2019

Very fine grain
Coarse grain
Medium grain
Fine grain

Explanation:

Medium grain size ranges between 30 and 70. Coarse: 10-24, Fine: 80-180, Very fine: 220-600.

The width of the grinding contact in a horizontal surface grinding machine is 15 mm, real depth of cut is 10 μm and work speed is 300 mm/s. The material removal rate is —-? RRB JE 30-08-2019

25 mm³/s
35 mm³/s
15 mm³/s
45 mm³/s

Explanation:

MRR = B × h × v = 15 × 10⁻³ × 300 = 4.5 mm³/s. Recalculating: h = 10 μm = 0.01 mm. MRR = 15 × 0.01 × 300 = 45 mm³/s.

Truing is the process of —-? RRB JE 30-08-2019

Heating the metal to critical temperature
Powder metallurgy
Metallic coating
Changing the shape of the grinding wheel

Explanation:

Truing is the process of changing the shape of the grinding wheel as it becomes worn from its original shape, owing to breaking away of abrasive and bond.

The silicon carbide abrasive is mainly used for grinding —-? RRB JE 30-08-2019

Cast iron
Ceramics
Cemented carbide
All of the options

Explanation:

Silicon carbide is recommended for grinding materials of low tensile strength like cast iron, brass, bronze, ceramics, and cemented carbide. Aluminium oxide is for high tensile strength materials.

Which of the following indicates the open structure of the grinding wheel? RRB-JE 30.08.2019, Ist Shift RRB JE 30-08-2019

Explanation:

Open structure is denoted by 9 to 15 or higher. Dense structure is denoted by 1 to 8. 12 indicates open structure, suitable for heavy cuts, soft, tough, and ductile materials.

Which of the following ratings for the grinding wheel is designated as soft? RRB JE 30-08-2019

A to I
I to K
Q to Z
J to P

Explanation:

A to H → Soft grade, I to P → Medium grade, Q to Z → Hard grade. Soft grade wheels are used for grinding hard materials and hard grade wheels for softer materials.

Which of the following is/are the types of cylindrical grinding? RRB JE 31-08-2019

Plunge grinding
Creep feed grinding
All of the options
Centreless grinding

Explanation:

Types of cylindrical grinding include plunge grinding, creep feed grinding, and centreless grinding. Cylindrical grinding may be internal or external.

The operation which is done to make periphery of grinding wheel concentric with its axis to recover its lost shape is known as —-? RRB JE 31-08-2019

Loading
Glazing
Truing
Dressing

Explanation:

Truing makes the periphery of grinding wheel concentric with its axis to recover its lost shape. Dressing removes loading and breaks away glazed surface.

Which of the following indicates the amount of superabrasive grit in grinding wheel? RRB JE 31-08-2019

Grade
Structure
Concentration
Grit

Explanation:

Concentration indicates the amount of superabrasive grit in the grinding wheel.

Grain size range between 90 and 220 is considered as —-? RRB JE 31-08-2019

Fine grain
Normal grain
Very fine grain
Coarse grain

Explanation:

Grain size 90-220 is considered fine grain. 10-24: Coarse, 30-60: Medium, 70-180: Fine, 220-600: Very fine.

The number ‘120’ in the grinding wheel R D 120 N 100 M specifies the —-? RRB JE 31-08-2019

Concentration number
Average grain size
Hardness of grinding wheel
Abrasive strength

Explanation:

In grinding wheel specification, 120 specifies the average grain size (grit number).

Which abrasive material is used in grinding wheel selected for grinding of ferrous alloy? (RRB Allahabad JE 09.09.2012)

Diamond
Boron carbide
Silicon carbide
Aluminum oxide

Explanation:

Aluminium oxide (Al₂O₃) – trade name Alundum – is used for grinding ferrous alloys.

Surface finish produced by electrochemical grinding on ‘Tungsten carbide’ can be expected to be the order of ____ micron. (DMRC JE 22.09.2017)

0.1 to 0.2
0.2 to 0.4
0.4 to 0.8
0.8 to 0.9

Explanation:

Electrochemical grinding on tungsten carbide produces surface finish of 0.2-0.4 micron.

In grinding wheel marked with A-48-L-7-V-25, what does L refer to? (JMRC JE 10.06.2017) RRB Bhopal & Mumbai Apprentice Section Engg. 23.03.2003

Abrasive type
Manufacture code
Wheel hardness
Wheel structure

Explanation:

L refers to Grade (wheel hardness). A to H: Soft grade, I to P: Medium grade, Q to Z: Hard grade.

If the hardness of grinding wheel is very hard then the designation of letter will be —-? (BMRCL JE 24 Feb.2019)

H to K
L to S
T to Z
A to G

Explanation:

A to H: Soft grade, I to P: Medium grade, Q to Z: Hard grade. T to Z represents very hard grade.

The grinding wheel is considered better, if the grinding ratio is —-? (RRB Bhubneshwar JE-11 19.12.2010)

maximum
very low
average
minimum

Explanation:

Grinding ratio = Volume of material removal / Volume of wheel wear. Higher the grinding ratio, better the grinding condition and longer wheel life.

Hardness of grinding wheel can be denoted as letters A to G for —-? (RRB Allahabad JE 19.12.2010)

Hard
Medium
Very soft
Soft

Explanation:

A to H: Soft grade (for harder materials), I to P: Medium grade, Q to Z: Hard grade (for softer materials).

Which unit is used for surface speed in grinding machine? (RRB Allahabad SSE 19.12.2010)

Ft/min
Ft/sec
Meter/sec
Meter/min

Explanation:

Surface speed in grinding machine is measured in m/s. V = πDN/(60×1000) m/s.

Structure of grinding wheel is denoted by —-? (RRB Mumbai JE 05.10.2008)

Letters
Numbers
Slashes
Words

Explanation:

Structure of grinding wheel is denoted by numbers. 0-7: Denser structure (finish grinding, hard materials), 8-16: Open structure (rough grinding, soft materials).

____ type of grinding wheel is used for higher rate of material removal. (RRB Mumbai SSE 05.10.2008)

Silicate bond
Vitrified bond
Shellac bond
Rubber bond

Explanation:

Vitrified bond is used for higher rate of material removal. It is the most commonly used bond in grinding wheels.

Which bond is commonly used in grinding wheel? (RRB Mumbai JE 19.12.2010)

Vitrified bond
Silicate bond
Shellac bond
Resinoid bond

Explanation:

Vitrified bond (Symbol – V) is the most commonly used bond in grinding wheels. Made of abrasive grain, clay, and water; also called ceramic bond.

In standard marking system of grinding wheel, the grain size 20 refers to —-? (RRB Mumbai SSE 19.12.2010)

Coarse
Medium
Very fine
Fine

Explanation:

8-24: Coarse grain (soft & ductile), 30-60: Medium grain, 80-180: Fine grain, 220-600: Very fine grain.

In the grinding wheel of A60 G7 B23, B stands for —-? (DMRC JE 2013)

Resinoid bond
Rubber bond
Shellac bond
Silicate Bond

Explanation:

B stands for Resinoid bond. V: Vitrified, S: Silicate, E: Shellac, B: Resinoid, R: Rubber, O: Oxychloride.

Which one of the following materials is used as the bonding material for grinding wheels? (ESE:1997) (RRB JE Ahmedabad 2014)

Silicon carbide
Sodium silicate
Boron carbide
Aluminium oxide

Explanation:

Sodium silicate is used as bonding material for grinding wheels when heat generated by grinding must be kept to a minimum.

Which one of the following is not used as abrasive material in grinding wheels? (DMRC JE 20.04.2018) (RRB Malda SSE 25.10.2009)

Aluminium oxide
Silicon carbide
Cubic boron nitride
Manganese oxide

Explanation:

Manganese oxide is not used as abrasive material in grinding wheels. Abrasives include Al₂O₃, SiC, CBN, and Diamond.

The hardness of a grinding wheel is determined by the —-? (Konkan Railway STA 2017)

Hardness of abrasive grains
Ability of the bond to retain abrasives
Hardness of the bond
Ability of the grinding wheel to penetrate the work piece

Explanation:

Hardness of bond is determined by the ability of bond to retain abrasive. Hardness order: Quartz → Al₂O₃ → SiC → CBN → Diamond.

Abrasives are not used in —-? (Konkan Railway TA 2017)

Buffing process
Burnishing process
Polishing process
Super finishing process

Explanation:

Abrasives are not used in burnishing process. Burnishing is a metal finishing process that uses pressure to smooth a surface without removing material.

In a grinding wheel marked with A-48-L-7-V-25, L refers to —-? (Konkan Railway SSE 2015)

Abrasive type
Wheel structure
Wheel hardness
Manufactures code

Explanation:

A-48-L-7-V: Abrasive (A) → Grain size (48) → Grade/Hardness (L) → Structure (7) → Bond (V). L shows wheel hardness.

The marking on a grinding wheel is ’51 A 36 L 5 V 93′. The code ’36’ represents the —-? (RRB JE (Shift-III), 30.08.2015)

Structure
Grade
Grain size
Manufacture’s number

Explanation:

36 represents grain size. 51 A 36 L 5 V 93: Abrasive → Grain size → Grade → Structure → Bond.

Which of the following is the natural abrasive? (RRB Kolkata Diesel JE 25.10.2009)

Al₂O₃
SiC
Boron carbide
Corundum

Explanation:

Natural abrasives include sandstone, corundum, emery, quartz, garnet, and diamond. Artificial abrasives include silicon carbide, aluminium oxide, cubic boron nitride.

A grinding wheel gets glazed due to —-? (RRB Mumbai C&G JE 25.10.2009)

wear of abrasive grains
wear of bond
breaking of abrasives
cracks in wheel

Explanation:

Glazing is caused by grinding hard materials on a wheel that has too hard a grade of bond. The abrasive particles become dull due to cutting hard material, and the bond is too firm to allow them to break out.

Which of the following is not a natural abrasive? (RRB Gorakhpur RDSO SSE 25.10.2009)

Garnet
Emery
Boron-carbide
Corundum

Explanation:

Boron carbide is an artificial abrasive. Natural abrasives include garnet, emery, corundum, sandstone, quartz, and diamond.

A grinding wheel is specified by C 70 G 7 R 23. Here C stands for —-? (RRB Jammu JE 25.10.2009)

Aluminium oxide
Silicon carbide
Diamond
Cubic boron nitride

Explanation:

C 70 G 7 R 23: C = Silicon carbide (abrasive type), 70 = Grain size, G = Grade, 7 = Structure, R = Rubber bond.