Tapers and Cutting Tapers

Use of Tapers

  • Tapers are used on machine tools to locate and hold arbors, cutters and other machine parts.
  • Tapers allow for repeated accurate location and alignment.

Taper Classifications

  • Locating
    • Held in machine with a draw bolt.
  • Self-Locking
    • Shallow taper causes taper to lock in place without a draw bar.

Specifying taper sizes

  • Imperial Tapers may be specified in:
    • Degrees
    • Taper per inch
    • Taper per foot
  • Metric Tapers are normally specified as a ratio.  i.e. 1:10  (Taper gets bigger by one millimeter for every 10 millimeters of length.)

Common Types of Tapers

  • Browne & Sharpe: ½ in per foot (Varies slightly depending on size).
  • Jarno: 0.600 inches per foot
  • Jacob’s
  • Standard National Milling Machine
    • Locating Taper
    • Held in machine spindle with a draw bar.
    • 16- ½ degree included angle
    • 3-1/2 inches per foot
    • Common sizes are #30, #40 #50 and #60
  • Morse
    • Approximately 5/8 inch taper per foot.  (Varies depending on taper size.)
    • Morse taper sizes are numbered from 0 to 7.  (7 is the largest)
Machining Tapers
  • Tapers are often machined on a lathe and then ground on a cylindrical grinder.
  • Tapers may be machined on a lathe using:
    • Form tools – Small chamfers.
    • The compound slide – Short, steep tapers.
    • The offset tailstock method – Long shallow tapers.
    • The taper turning attachment – Up to approx. 15º
      • Standard (Plain) type
      • Telescoping type
Measuring Tapers
  • Micrometer method
  • Parallel bars and rods
  • Taper plug or ring gauge
  • Sine bar and gauge blocks

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