1

GATE PI 1990

MCQ (Single Correct Answer)

+5

-1.5

A parting tool has a ground front clearance angle of $${6^0}$$ and the back rake angle of $${10^0}$$. The tool, by mistake, was set $$1.5$$ $$mm$$ above the line of centers while machining a job of $$50$$ $$mm$$ out-side diameter.

The diameter of the job at which, while parting, the tool will start rubbing

2

GATE PI 1990

Subjective

+5

-0

The following data apply to machining a part on turret lathe and a general purpose lathe

The setup cost and the cost for special tooling on the turret lathe would be $$Rs.3000/-.$$ These costs are negligible on the general purpose lathe. Calculate the batch seize which justifies the use of turret lathe.

3

GATE PI 1989

Subjective

+5

-0

Calculate the tonnage capacity of the broaching machine required to broach on the hole under the following conditions.

Diameter of the finished hole $$=75mm,$$

rise per tooth $$=0.03mm$$

Tooth pitch $$=10mm,$$

Length of the broach $$=750mm$$

Cutting speed $$=6m/min,$$

specific cutting pressure $$ = 1300 \times {t^{0.4}}\,\,N/m{m^2},$$ (Where $$t$$ is the uncut chip thickness)

If the tool and work handling time is $$0.5min,$$ estimate the production rate per hour

Diameter of the finished hole $$=75mm,$$

rise per tooth $$=0.03mm$$

Tooth pitch $$=10mm,$$

Length of the broach $$=750mm$$

Cutting speed $$=6m/min,$$

specific cutting pressure $$ = 1300 \times {t^{0.4}}\,\,N/m{m^2},$$ (Where $$t$$ is the uncut chip thickness)

If the tool and work handling time is $$0.5min,$$ estimate the production rate per hour

4

GATE PI 1989

Subjective

+5

-0

The results of machining steel with $$2$$ grades of tool material are given below. For a $$180$$ $$min.$$ Tool life which tool is recommended and why?

If the tool regrinding and changing time is $$15min,$$ the cutting speed for tool $$A$$ $$ahs$$ to be chosen ($$40m/min$$ or $$50m/min$$)

Questions Asked from Metal Cutting (Marks 5)

Number in Brackets after Paper Indicates No. of Questions

GATE PI Subjects

Fluid Mechanics

Metrology

Theory of Machines

Engineering Mathematics

Machine Tools and Machining

Industrial Engineering

Engineering Mechanics

Strength of Materials

Thermodynamics

Machine Design

Casting

Joining of Materials

Metal Forming