21. The abrasive recommended for grinding materials of high tensile strength is
A. silicon carbide
B. aluminium oxide
C. sand stone
D. diamond
22. The factor responsible for the formation of continuous chips with built up edge is
A. low cutting speed and large rake angle
B. low cutting speed and small rake angle
C. high cutting speed and large rake angle
D. high cutting speed and small rake angle
23. An important geometrical quantity in the cutting of metals which can be used as a criterion for machinability of metals is
A. cutting speed
B. feed rate
C. shear angle
D. tool geometry
24. In centreless grinding, the surface speed of regulating wheel is
A. 5 to 15 m/min
B. 15 to 60 m/min
C. 60 to 90 m/min
D. 90 to 120 m/min
25. In metal cutting, use of low feeds and high cutting speeds is desired when the objective is
A. high metal removal rate
B. dry machining
C. use of soft cutting tool
D. surface finish
26. The angle on which the strength of the tool depends is
A. rake angle
B. cutting angle
C. clearance angle
D. lip angle
27. Larger than 15° side cutting edge angle
A. increases tool life
B. decreases tool life
C. produces chipping and decreases tool life
D. results in excessive stress concentration and greater heat generation
28. Which of the following statement is correct for orthogonal cutting system?
A. The cutting edge of the tool is perpendicular to the direction of tool travel.
B. The cutting edge clears the width of the workpiece on either ends.
C. The chip flows over the tool face and the direction of the chip flow velocity is normal to the cutting edge.
D. all of the above
29. The angle made by the face of the tool and the plane parallel to the base of cutting tool is called
A. rake angle
B. cutting angle
C. clearance angle
D. lip angle
30. In case of turning, as the machining proceeds, the spindle speed must __________ with the decrease in diameter of work.
A. decrease
B. increase
31. Back rake angle of a single point tool is the angle by which the face of the tool is inclined towards back.
A. Agree
B. Disagree
32. As the cutting speed increases, tool life decreases.
A. Yes
B. No
33. In metal machining, the work-tool contact zone is a zone where heat is generated due to
A. plastic deformation of metal
B. burnishing friction
C. friction between the moving chip and the tool face
D. none of the above
34. Thread grinding requires work speed from
A. 1 to 3 m/min
B. 5 to 10 m/min
C. 10 to 14 m/min
D. 14 to 20 m/min
35. Threading is an operation of
A. smoothing and squaring the surface around a hole
B. sizing and finishing a small diameter hole
C. producing a hole by removing metal along the circumference of a hollow cutting tool
D. cutting helical grooves on the external cylindrical surface
36. Glazing in grinding wheels can be decreased by
A. using a harder wheel or by increasing the wheel speed
B. using a softer wheel or by decreasing the wheel speed
C. using a harder wheel or by decreasing the wheel speed
D. using a softer wheel or by increasing the wheel speed
37. The cutting speed is minimum while machining __________ with a high speed steel tool.
A. cast iron
B. mild steel
C. brass
D. aluminium
38. A process of removing metal by pushing or pulling a cutting tool is called
A. up milling
B. down milling
C. forming
D. broaching
39. The hardness of a grinding wheel is specified by
A. Brinell hardness number
B. Rockwel! hardness number
C. Vickers pyramid number
D. letter of alphabet
40. Which of the following operations can be performed with milling cutters?
A. cutting key ways on shafts
B. cutting external screw threads
C. cutting teeth of spur gears
[D. all of these