41. The machining of titanium is difficult due to
A. high thermal conductivity of titanium
B. chemical reaction between tool and work
C. low tool-chip contact area
D. none of these
42. In orthogonal cutting system, the maximum chip thickness occurs at the middle.
A. Correct
B. Incorrect
43. Lapping is an operation of
A. making a cone-shaped enlargement of the end of a hole
B. smoothing and squaring the surface around a hole
C. sizing and finishing a small diameter hole
D. producing a hole by removing metal along the circumference of a hollow cutting tool
44. The different spindle speeds on a lathe form
A. arithmetical progression
B. geometrical progression
C. harmonical progression
D. any one of these
45. If the helix angle of the drill is made __________ 30°, then the torque required to drive the drill at a given feed will be more.
A. equal to
B. less than
C. more than
46. The angle included between the two lips projected upon a plane parallel to the drill axis and paralleled to the two cutting lips, is called helix angle.
A. Correct
B. Incorrect
47. In hot machining, tool is made of
A. tungsten carbide
B. brass or copper
C. diamond
D. stainless steel
48. In ultra-sonic machining, the metal is removed by
A. using abrasive slurry between the tool and work
B. direct contact of tool with the work
C. maintaining an electrolyte between the work and tool in a very small gap between the two
D. erosion caused by rapidly recurring spark discharges between the tool and work
49. The velocity of tool relative to the workpiece is known as cutting velocity.
A. True
B. False
50. Grinding wheels should be tested for balance
A. only at the time of manufacture
B. before starting the grinding operation
C. at the end of the grinding operation
D. occasionally