21. Tool life is generally better when
A. grain size of the metal is large
B. grain size of the metal is small
C. hard constituents are present in the microstructure of the tool material
D. none of the above
22. When the metal is removed by erosion caused by rapidly recurring spark discharges between the tool and work, the process is known as
A. electro-chemical machining
B. electro-discharge machining
C. ultra-sonic machining
D. none of these
23. Cemented carbide tools are generally poor in shear.
A. Yes
B. No
24. Which of the following statement is wrong as regard to down milling?
A. It can not be used on old machines due to backlash between the feed screw of the table and the nut.
B. The chips are disposed off easily and do not interfere with the cutting.
C. The surface milled appears to be slightly wavy.
D. The coolant can be poured directly at the cutting zone where the cutting force is maximum.
25. In reaming process
A. metal removal rate is high
B. high surface finish is obtained
C. high form accuracy is obtained
D. high dimensional accuracy is obtained
26. The lathe spindles at the nose end have
A. internal screw threads
B. external screw threads
C. no threads
D. tapered threads
27. The lip clearance angle is the angle formed by the
A. leading edge of the land with a plane having the axis of the drill
B. flank and a plane at right angles to the drill axis
C. chisel edge and the lip as viewed from the end of a drill
D. none of the above
28. Flank wear occurs mainly on the
A. nose part, front relief face and side relief face of the cutting tool
B. face of the cutting tool at a short distance from the cutting edge
C. cutting edge only
D. front face only
29. The process of changing the shape of grinding wheel as it becomes worn due to breaking away of the abrasive and bond, is called
A. truing
B. dressing
C. facing
D. clearing
30. The infeed grinding is similar to plunge grinding.
A. Yes
B. No
31. The cutting angle of a flat drill varies from
A. 3° to 8°
B. 20° to 30°
C. 60° to 90°
D. 90° to 120°
32. In electro-discharge machining, dielectric is used to
A. help in the movement of the sparks
B. control the spark discharges
C. act as coolant
D. all of these
33. In metal cutting operations, the shear angle is the angle made by the shear plane with the
A. direction of the tool axis
B. direction of tool travel
C. perpendicular to the direction of the tool axis
D. central plane of the workpiece
34. The floating position of the holding fixture in a rotary transfer device is used to
A. improve the accuracy of location
B. reduce the tendency to over-index
C. improve upon the acceleration and deceleration characteristics
D. reduce the cycle time
35. The operation of smoothing and squaring the surface around a hole is known as
A. counter-sinking
B. counter-boring
C. trepanning
D. spot facing
36. The cutting force in down milling is maximum when the tooth begins its cut and reduces to minimum when the tooth leaves the work.
A. Correct
B. Incorrect
37. The ductile materials, during machining, produce
A. continuous chips
B. discontinuous chips
C. continuous chips with built up edge
D. either (a) or (c)
38. Slow speed of the spindle is necessary in
A. thread cutting
B. turning a work of larger diameter
C. turning a hard or tough material
D. all of these
39. The hole drilled for tapping should be smaller than the tap size by twice the depth of thread.
A. Agree
B. Disagree
40. Relief angles on high speed steel tools usually vary from
A. 0° to 3°
B. 3° to 10°
C. 10° to 20°
D. 20° to 30°