Q1: A flat surface of a C60 steel having dimensions of 100 mm (length) × 200 mm (width) is produced by a HSS slab mill cutter. The 8-toothed cutter has 100 mm diameter and 200 mm width. The feed per tooth is 0.1 mm, cutting velocity is 20 m/min and depth of cut is 2 mm. The machining time required to remove the entire stock is ______ minutes (rounded off to 2 decimal places). [GATE ME 2024 ]Ans: 2.2 to 2.65
Data given:
Z = 8, D = 100 mm, w = 200 mm
V = 20 m/min, d = 2 mm, ft = 0.1 mm/ tooth
N = ?

Le = effective length of approach = QR + L = 14 + 100 = 114 mm
= For removal of entire length
So, feed = ft × NZ = 0.1 × 63.662 × 8 = 50.93 mm/min
tm/c = Le/F = 114/50.93 = 2.24 min
Q2: A cutting tool provides a tool life of 60 minutes while machining with the cutting speed of 60 m/min. When the same tool is used for machining the same material, it provides a tool life of 10 minutes for a cutting speed of 100 m/min. If the cutting speed is changed to 80 m/min for the same tool and work material combination, the tool life computed using Taylor's tool life model is _____ minutes (rounded off to 2 decimal places). [GATE ME 2024]
Ans: 21 to 22.5
Taylor Tool Life Equation
VTn = Constant
Given : V1 = 60(m/min), T1 = 60 min
V2 = 100(m/min), T2 = 10 min
So, to find out 
InV1 + n nnT1 = lnV2 + nlnT2
lnV1 - InV2 = n[lnT2 - InT1]

Now, V3 = 80 m/min, T3 = ?

So,
=100 × 100.285
⇒ T3 = 21.87 min
Q3: The grinding wheel used to provide the best surface finish is [GATE ME 2024]
(a) A36L5V
(b) A54L5V
(c) A60L5V
(d) A80L5V
Ans: (d)
Grinding Wheel Components :
Abrasive Type A60-M5-V
Abrasive size A60-M5-V
Grade/Hardness A60-M5-V
Structure A60-M5-V
Bond A60-M5-V

Fig. Specification of grinding wheel
Fine and superfine grain size give best surface finish.
Q1: A solid part (see figure) of polymer material is to be fabricated by additive manufacturing (AM) in square-shaped layers starting from the bottom of the part working upwards. The nozzle diameter of the AM machine is a/10 mm and the nozzle follows a linear serpentine path parallel to the sides of the square layers with a feed rate of a/5 mm/min.
Ignore any tool path motions other than those involved in adding material, and any other delays between layers or the serpentine scan lines.
The time taken to fabricate this part is _______ minutes. (Answer in integer) [GATE ME 2023]
Ans: 9000 to 9000
V = (3a)2 × 1.5a + (2a)2 × a + (a)2 × 0.5a
= 18a3

= (18a3/a3) x 100 x 5 = 9000 min
Q2: In an ideal orthogonal cutting experiment (see figure), the cutting speed V is 1 m/s, the rake angle of the tool α = 5º, and the shear angle, ϕ, is known to be 45º.
Applying the ideal orthogonal cutting model, consider two shear planes PQ and RS close to each other. As they approach the thin shear zone (shown as a thick line in the figure), plane RS gets sheared with respect to PQ (point R1 shears to R2, and S1 shears to S2).
Assuming that the perpendicular distance between PQ and RS is δ = 25 μm, what is the value of shear strain rate (in s-1) that the material undergoes at the shear zone? [GATE ME 2023]
(a) 1.84 × 104
(b) 5.20 × 104
(c) 0.71 × 104
(d) 1.30 × 104
Ans: (b)
Data given α = 5º
ϕ = 45º
ΔH = 25 μm
V = 1 m/sec

Shear strain rate =
= 5.20 x 104s-1
Q3: A cuboidal part has to be accurately positioned first, arresting six degrees of freedom and then clamped in a fixture, to be used for machining. Locating pins in the form of cylinders with hemi-spherical tips are to be placed on the fixture for positioning. Four different configurations of locating pins are proposed as shown. Which one of the options given is correct? [GATE ME 2023]
(a) Configuration P1 arrests 6 degrees of freedom, while Configurations P2 and P4 are over-constrained and Configuration P3 is under-constrained.
(b) Configuration P2 arrests 6 degrees of freedom, while Configurations P1 and P3 are over-constrained and Configuration P4 is under-constrained.
(c) Configuration P3 arrests 6 degrees of freedom, while Configurations P2 and P4 are over-constrained and Configuration P1 is under-constrained.
(d) Configuration P4 arrests 6 degrees of freedom, while Configurations P1 and P3 are over-constrained and Configuration P2 is under-constrained.
Ans: (a)
3-2-1 principle of location
The 3-2-1 principle of location (six point location principle) is used to constrain the movement of workpiece along the three axes XX, YY and ZZ.
This is achieved by providing six locating points, 3-pins in base plate, 2-pins in vertical plane and 1-pin in a plane which is perpendicular to first two planes.
Q1: In an orthogonal machining operation, the cutting and thrust forces are equal in magnitude. The uncut chip thickness is 0.5 mm and the shear angle is 15º. The orthogonal rake angle of the tool is 0º and the width of cut is 2 mm. The workpiece material is perfectly plastic and its yield shear strength is 500 MPa. The cutting force is _________ N (round off to the nearest integer). [GATE ME 2022 SET-2]
Ans: 2700 to 2750
Given, FC = FT
Uncut chip thickness (t1) = 0.5mm
Shear angle (ϕ) = 15º
Orthogonal rake angle α = 0º
Width of cut w = 2mm
Shear strength (τS) = 500MPa
Cutting force fc = ____ N
FS = FC cosϕ - FT sinϕ
= FC cosϕ - FC sinϕ
= FC (cosϕ - sinϕ)


= 2732 N.
Q2: A straight-teeth horizontal slab milling cutter is shown in the figure. It has 4 teeth and diameter (D) of 200 mm. The rotational speed of the cutter is 100 rpm and the linear feed given to the workpiece is 1000 mm/minute. The width of the workpiece (w) is 100 mm, and the entire width is milled in a single pass of the cutter. The cutting force/tooth is given by F = Ktcw, where specific cutting force K = 10N/mm2, w is the width of cut, and tc is the uncut chip thickness.
The depth of cut (dd) is D/2, and hence the assumption of d/D << 1 is invalid. The maximum cutting force required is __________ kN (round off to one decimal place). [GATE ME 2022 SET-2]
Ans: 2.4 to 2.6
Given data, No. of teeth (n) = 4
Diameter of cutter (D) = 200mm
Rotational speed (N) = 100rpm
Linear feed to work piece = 1000 mm/min
Width of work piece (w) = 100mm
Cutting force/tooth = F = Ktcw
Specific cutting force = K = 10N/mm2
Depth of cut (d) = D/2
Feed (f) = 1000/100 = 10mm/rev
Uncut chip thickness = tc
Maximum uncut chip thickness (tc)max

Non traditional thermal energy process includes electrical discharge machining (EDM), electron beam machining (EBM), and laser beam machining (LBM). EDM removes metal by a series of discrete electrical discharge (sparks) that cause localized temperatures high enough to melt or vaporize the metal in the immediate vicinity of the discharge. EBM adopts a high velocity stream of electrons focused on the workpiece surface to remove material by melting and vaporization. LBM employs the light energy from a laser to remove material by vaporization and ablation.

Ignore overpotentials, and assume that current efficiency is 100% for both the workpiece materials. Under identical conditions, if the material removal rate (MRR) of copper is 100 mg/s, the MRR of aluminum will be ________________ mg/s (roundoff to two decimal places). [GATE ME 2022 SET-1]

(Vc = chip velocity; V = cutting velocity)






Q5: An orthogonal cutting operation is performed using a single point cutting tool with a rake angle of 12º on a lathe. During turning, the cutting force and the friction force are 1000 N and 600 N, respectively. If the chip thickness and the uncut chip thickness during turning are 1.5 mm and 0.75 mm, respectively, then the shear force is _______N (round off to two decimal places). [GATE ME 2021 SET-1]
Ans: 625 to 750
Fc = 1000 N, F = 600 N, t = 0.75 mm, tc = 1.5 mm, α = 12º
This is orthogonal turning operation
⇒ ϕ = 28.63º
Method - 1: Using force relations
F = Fc sin α + Ft cos α
600 = 1000 sin 12º + ft cos12º
or Ft = 400.85 N
∴ Fs = Fc cosϕ - Ft sinϕ
= 1000 cos 28.63º - 400.85 sin28.63º
= 685.66 N
Method - 2 : Using Merchant circle
Fc = Rcos(β - α)
F = R sinβ
or 


0.6 cos β cos12º + 0.6 sin β sin12º = sinβ
0.586888 cos β = (1 - 0.6 sin 12º) sinβ = 0.875253 sin β
⇒ β = 33.84º
∴ F = R sin β
600 = R sin 33.84º
⇒ R = 1077.44 N
∴ Fs = R cos (ϕ + β - α)
= 1077.44 cos (28.63º + 33.84º - 12º)
= 685.77 N
Q6: The correct sequence of machining operations to be performed to finish a large diameter through hole is [GATE ME 2021 SET-1]
(a) drilling, boring, reaming
(b) boring, drilling, reaming
(c) drilling, reaming, boring
(d) boring, reaming, drilling
Ans: (a)
Drilling: to produce a hole, which then may be followed by boring it to improve its dimensional accuracy and surface finish.
Boring: to enlarge a hole or cylindrical cavity made by a previous process or to produce circular internal grooves.
Reaming: is an operation used to (a) make an existing hole dimensionally more accurate than can br achived by drilling alone and (b) improve its surface finish. The most accurate holes in workpieces generally are produced by the following sequence of operation.
Centering -> Drilling -> Boring -> Reaming.
Q7: In a machining operation, if a cutting tool traces the workpiece such that the directrix is perpendicular to the plane of the generatrix as shown in figure, the surface generated is [GATE ME 2021 SET-1]
(a) plane
(b) cylindrical
(c) spherical
(d) a surface of revolutio
Ans: (b)
Q1: Bars of 250 mm length and 25 mm diameter are to be turned on a lathe with a feed of 0.2 mm/rev. Each regrinding of the tool costs Rs. 20. The time required for each tool change is 1 min. Tool life equation is given as VT0.2 = 24 (where cutting speed V is in m/min and tool life T is in min). The optimum tool cost per piece for maximum production rate is Rs. ________ (round off to 2 decimal places). [GATE ME 2020 SET-2]
Ans: 26 to 28
Optimum tool life 


= 24/40.2 = 18.19 m/min
V = πDN
⇒ 18.19 = π x 0.025 x N
⇒ N = 231.6 rpm
Maching time per piece
Number of tool needed per piece work = 5.397/4 piece
∴ The optimum tool cost per piece = (5.397/4) x 20 = 26.985
Q2: A cylindrical bar with 200 mm diameter is being turned with a tool having geometry 0°-9°-7°-8°-15°-30°-0.05 inch (Coordinate system, ASA) resulting in a cutting force Fc1. If the tool geometry is changed to 0°-9°-7°-8°-15°-0°-0.05 inch (Coordinate system. ASA) and all other parameters remain unchanged, the cutting force changes to Fc2. Specific cutting energy (in J/mm3) is Uc = U0(t1) - 0.4, where U0 is the specific energy coefficient, and t1 is the uncut thickness in mm. The value of percentage change in cutting force Fc2, i.e.
is _______ (round off to one decimal place). [GATE ME 2020 SET-2]
Ans: -5.8 to -5.5
Cs1 = 30°
∴ λ1 = 90 - 30 = 60°
Cs2 = 0°
∴ λ2 =90 - 0 = 90°
We know that specific energy consumption

Q3: The process, that uses a tapered horn to amplify and focus the mechanical energy for machining of glass, is [GATE ME 2020 SET-2]
(a) electrochemical machining
(b) electrical discharge machining
(c) ultrasonic machining
(d) abrasive jet machining
Ans: (c)
In Ultrasonic machining, the function of horn (also called concentrator, it is a tapered metal bar) is to amplify and focus vibration of the transducer to an adequate intensity for driving the tool to fulfll the cutting operation.
Q4: In a turning process using orthogonal tool geometry, a chip length of 100 mm is obtained for an uncut chip length of 250 mm.
The cutting conditions are cutting speed = 30 m/min. rake angle = 20º.
The shear plane angle is _________ degrees (round off to one decimal place). [GATE ME 2020 SET-1]
Ans: 22 to 25

ϕ = tan-1(0.4354) = 23.5º.
Q5: The following data applies to basic shaft system:
tolerance for hole = 0.002 mm,
tolerance for shaft = 0.001 mm,
allowance = 0.003 mm,
basic size = 50 mm.
The maximum hole size is ______ mm (round off to 3 decimal places). [GATE ME 2020 SET-1]
Ans: 50.005 to 50.005
Using diagram method
UL of hole = BS + 0.003 + 0.002 mm = 50.005 mm
Q6: The base of a brass bracket needs rough grinding. For this purpose, the most suitable grinding wheel grade specification is [GATE ME 2020 SET-1]
(a) C30Q12V
(b) A50G8V
(c) C90J4B
(d) A30D12V
Ans: (a)
Base of brass bracket need rough grinding, for this purpose the most suitable grinding wheel grade specifcation is C30Q12V.
Because 30 is a grain number.
Try yourself: Grinding ratio is defined as Volume of wheel wear
Try yourself: The binding material used in cemented carbide cutting tools is [PI 2011]
Try yourself: During turning of a low carbon steel bar with TiN coated carbide insert, one needs to improve surface finish without sacrificing material removal rate. The achieve improved surface finish one should [PI 2010]
Try yourself: A side and face cutter 125 mm diameter has 10 teeth. If operates at a cutting speed of 14 m/ min with a table traverse 100 mm/min the feed per tooth of the cutter is [PI 2002]
Try yourself: A grinding wheel is said to be glazed if [PI 1995]
Try yourself: If the index crank of a dividing head is turned through one complete revolution and 10 holes in a 30 hole Circle plate, the workpiece turns through (in degrees) [PI 1992]
Try yourself: Find the speed range ratio for the drilling machine spindle if the minimum and maximum diameters of drills used are 5 mm and 25 mm respectively and if the machinability indices for the work materials are 120 (brass) and 40 (alloy steel) [PI 1992]
Try yourself: In a grinding wheel marked with AA-48-L-7-V25, L refers to [PI 1992]
Try yourself: A drilling machine has to be designed with 8 spindle speeds ranging approximately between 120 to 1200 rpm. The 5th spindle speed is [PI 1991]
Try yourself: Assertion (A): Single start threads are used for fastening purposes. [PI 1990]
Reason (R): Single start threads are easier to produce in a lathe.
Try yourself: The length, width and thickness of a steel sample are 400 mm, 410 mm, 40 mm and 20 mm, respectively. Its thickness needs to be uniformly reduced by 2 mm in a single pass by using horizontal slab miling. The miling cutter (diameter : 100 mm, width ; 50 mm) has 20 teeth and rotates at 1200 rpm. The feed per tooth is 0.05 mm. The feed direction is along the length of the sample. If the over-travel distance is the same as the approach distance, the approach distance and time taken to complete the required machining task are : [ME 2019,Set-1]
Try yourself: Better surface finish is obtained with a large rake angle because [ME 2014,Set-4]
Try yourself: Cutting tool is much harder than the workpiece.Yet the tool wears out during the tool-work interaction, because [ME 2014,Set-3]
Try yourself: The time taken to drill a hole through a 25 mm thick plate with the drill rotating at 300 rpm and moving at a feed rate of 0.25 mm/rev is [ME 2002]
Try yourself: The hardness of a grinding wheel is determined by the [ME 2002]
Try yourself: A conventional lathe and a CNC lathe are under consideration for machining a given part. The relevant data are shown below: [ME 2000]

The machine preferred for producing 100 pieces is
Try yourself: Abrasive material used in grinding wheel selected for grinding ferrous alloys is [ME 2000]
Try yourself: Plain milling of mild steel plates produces [ME 1995]
Try yourself: Among the conventional machining processes, maximum specific energy is consumed in [ME 1995]
Try yourself: Cutting power consumption in turning can be significantly reduced by [ME 1995]
Try yourself: A grinding wheel A 27 K 7 V is specified for finish grinding of a HSS cutting tool. What do you understand about the wheel from the above code. [ME 1994]
Is this an appropriate choice?
Try yourself: A milling cutter having 8 teeth is rotating at 150 rpm. If the feed per tooth is 0.1 mm, the speed in mm per minute is [ME 1993]
Try yourself: A milling cutter having 10 teeth is rotating at 100 rpm. The table feed is set at 50-mm per minute. The feed per tooth in mm is [ME 1991]
Try yourself: For cutting double start screw threads of pitch 1.0 mm on a lathe, the thread cutting tool should have a feed rate of [ME 1991]
Try yourself: If the longitudinal feed in centreless grinding is expressed by Vf = πDN sinα, D stands for [ME 1990]
Try yourself: Pure metal pose machinability problem in turning operations. The reason is the [ME 1988]
Try yourself: Cutting speed in grinding is set to a high value to [ME 1988]
Try yourself: The ideal cutting fluid for low speed machining of metals should be one which [ME 1988]
Try yourself: If in a turning operation both the feed rate and the nose radius are doubled the surface finish value will be [ME 1987]
Try yourself: The standard specification of a grinding wheel is A-46-M-6-V-21. It means a wheel of [ME 1987]
| 1. What are the most common machining processes covered in GATE Mechanical Engineering? | ![]() |
| 2. How can I prepare for the machining processes section in the GATE exam? | ![]() |
| 3. What is the significance of cutting tool materials in machining processes? | ![]() |
| 4. What role do machining parameters play in the machining process? | ![]() |
| 5. How is the concept of surface finish relevant in machining processes? | ![]() |