806. The helix angle on a HSS twist drill for drilling cast iron is of the order of
A.14 - 22°
B.24 - 32°
C.35 - 40°
D.40 - 45°

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807. Twist fluted drills are preferred because
A.It cuts holes efficiently
B.Chips move out automatically
C.Cutting lip is supported rigidly
D.It moves swiftly in the metal

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808. A portable drilling machine is specified by
A.The size of the job it can hold
B.Maximum diameter of drill it can hold
C.Spindle speeds and feeds
D.Maximum spindle travel

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809. The important purpose of flutes in a drill is that they enable the
A.Cutting fluid to enter the working zone
B.Cutting edges to be formed
C.Strength of the drill at the cutting point
D.Weight of the drill to be reduced

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810. The usual value of helix angle of a drill is
A.10°
B.20°
C.30°
D.60°

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811. The point angles and clearance angles of drills depend on
A.Drill diameter
B.Material to be drilled
C.R.p.m. of the drill
D.Depth of the hole to be drilled

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812. The rake angle of a single point cutting tool corresponds to following angle of a twist drill
A.Point angle
B.Helix angle
C.Lip diameter angle
D.Chisel edge angle

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