Page 102 - Turner 1st sem Practicals

Job sequence

TASK 1: Grinding R.H and L.H tools

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• Rotate the wheel by hand and observe for free rotation. • Rough grind the end cutting edge angle of 30 and the
front clearance angle of 4° simultaneously.
• Check the grinding wheels for true running.
• Hold the top flank of the tool against the wheel face
• Wear goggles.
inclined at 14°, the rear side contacting the wheel first,
• Dress the wheels by a wheel dresser. and grind the side rake angle of 14°.
• Adjust the tool-rest to maintain a minimum gap from • Ensure that the ground portion is parallel to the side
the wheel face to a minimum of 2 to 3 mm. cutting edge.
• Hold and apply the side flank of the tool to the front • Finish grind all the faces on the finishing wheel.
face of the grinding wheel at 30° to horizontal.
• Grind a nose radius of approximately R. 0.4 mm.
• Move the tool left to right and vice versa to grind the • Check the angles with a tool angle gauge and template.
side cutting edge angle to cover 2/3 width of the tool.
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• Lap the cutting edge with an oilstone.
• Grind a side clearance angle of 8°, the bottom of the
edge touching the wheel first. • The top rake (back rake) angle should be kept at 4°.
• To prepare L.H tool follow the same procedure.

TASK 2 : Grinding 'V' Threading tools (Metric)

• Set the pedestal grinder for tool grinding and make sure • Repeat the above procedure for right hand side to get
it is safe to start. the included angle of 60 .
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• Remove excess material on right hand side of the tool • Grind the top rake angle, back rake angle of 14 o
to length equal to the thickness of tool and width.
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• Grind the front clearance angle of 7 , the bottom of the
• Adjust the tool test to maintain a minimum gap from the edge touching the wheel first.
wheel face of 2 to 3 mm. • Lap the cutting edge with an oilstone.
• Wear the goggles, start the wheel, hold the tool firm at Precautions:
an angle of approximately 60 to the face of the wheel,
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grind the left hand side of tool. • Wear goggle
• Avoid burning of tool by using suitable coolant.

TASK 3: Grinding side cutting tool

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• Check the gap between the wheel and the tool rest, • Grind the top of the tool for a side rake angle of 12 to
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and maintain the gap 2 to 3 mm. 15 .
Damages or any corrections needed should be • Finish grind all angles and clearances - on a smooth
brought to the notice of instructor. wheel.
• Grind a nose radius of approximately R 0.5 mm.
• Hold the blank against the wheel to grind the end cutting
edge angle 20 to 25 and the front clearance angle The ground surfaces should be without steps
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between 6 to 8 - simultaneously. and should have a uniform smooth finish.
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o
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• Grind the side of the tool - for giving 6 to 8 side
clearance. The side length should be equal to the width
of the tool blank.
TASK 4: Grinding parting tool

• Set the pedestal grinder for tool grinding. • Grind Half of the thickness of tool on rough grinding
wheel.
• Remove excess of material on right hand side of the
tool to length equal to the thickness of tool and width. • Grind 4° to 6° front clearance angle.

Producltion & Manufacturing : Turner - Exercise 1.3.29 89