KEVOS® MAKEOS · Quality

Taper and Angle Gauges with Discs

What angle or taper do these two discs set, or where must they be placed for a required taper?

Angle and taper per foot set by two discs at a centre distance, the centre distance for a required angle or taper (on the centre-line or from one side), and the disc size for a given angle, using the handbook’s disc gauge rules.

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How this tool works

Inputs, units and where to find them

InputUnitTypical source
CalculatechoiceWhat to calculate.
Large disc diameterinDiameter of the larger disc.
Small disc diameterinDiameter of the smaller disc.
Centre distanceinDistance between disc centres.
Included angle°Required included angle.
Taper per foot (on diameter)in/ftRequired taper per foot (change in diameter over 12 in), measured on the centre-line or from one side as selected.

Method and formulas

  1. K = (D − d) ÷ 2C; included angle = 2 arcsin K; taper per foot = 24K ÷ √(1 − K²); from one side T = 24K √(1 − K²) ÷ (1 − 2K²).
  2. Centre distance for taper T: C = (D − d)/2 × √(1 + (T/24)²) ÷ (T/24); for an angle: C = (D − d) ÷ 2 sin(α/2).
  3. Centre distance for a taper from one side: C = (D − d) ÷ √(2 − 2 ÷ √(1 + (T/12)²)). Disc to touch at an angle: D = d (1 + sin(α/2)) ÷ (1 − sin(α/2)).
  4. Example (handbook case): 1.5 and 1 in discs at 5 in give 5.732° and 1.2015 in/ft.

Limitations

  • Inch units with taper per foot as in the handbook rules; convert metric tapers to the same basis.
  • Discs must be round and of known diameter.
  • Example values are illustrations. Replace them with values for your actual task.

Typical uses

  • Set up a disc gauge for checking tapers
  • Find the taper given by a disc set-up
  • Size a disc to contact a reference disc at an angle

Who it is for

  • Quality inspectors
  • Toolmakers
  • Metrology technicians

What you get

  • Included angle
  • Taper per foot (centre-line and from one side)
  • Centre distance or disc diameter

Interpreting the result

  • Use gauge blocks between disc centres or a sine bar to set the centre distance accurately.

References

  • Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 684–685. Topic reference; no source tables or recommended settings are reproduced.

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Open the Taper and Angle Gauges with Discs calculator