Counter Bore

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Counter Bore
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• Spot Facing Provides a true bearing surface for
  a washer.
• Counter boring Provides a recess for a bolt
  head, bushing or pin.

3
Tool construction

• Similar to an end mill, cuts on the end.
• Different from an end mill in that there is no
  cutting edge on the outside diameter.
• Normally spiral angle of 15 degrees. Brass
  requires straight flutes.

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Rotary table

• Adding another axis to the mill

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• Speeds production of hole patters
• Allows milling of curves, pockets, channels where
  not easily done otherwise.

• Horizontal

• Vertical

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Fixture

• Fixture Plate

• Chuck

• Toe clamp

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Part Location

• Co Axial indicator (Co-ax indicator)
• Simple means of center locating in round parts.
• May be run at LOW speeds when indicating

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Process

• Deck part using mill and rotary table
• Locate center
• C- bore to depth of .250