Taper per Foot and Angle
Taper per foot and per inch, plus the included and per-side angles, from two diameters.
Example
You enter
- Large diameter D (in) 1
- Small diameter d (in) 0.75
- Length over taper L (in) 3
You get
- Taper per foot 1
- Tpi (in) 0.0833333
- Angle per side (compound set) 2.38594 deg
- Included angle 4.77189 deg
Checked against published worked examples from: U.S. Navy, Naval Education and Training Command.
Details, formula, and sources
ScopeTaper per foot, taper per inch, and the included and per-side angles of a taper from the large and small diameters and the length: TPF = 12 x (D - d) / L, angle/side = atan((D - d) / 2L) (first-principles trigonometry).
Formula or tableTaper per inch = (D - d) / L; taper per foot = TPI x 12; angle per side = atan((D - d) / (2L)); included angle = 2 x (angle per side).
Source and editionTaper definitions and the taper-per-foot / angle relations - first-principles trigonometry as in Machinery's Handbook (Industrial Press), by name; public domain.
Free accessPure trigonometry, public.
What governsEstimate. AHJ and licensed professional govern.
API field nameslarge_dia_in, small_dia_in, length_in, tpf_in, tpi_in, angle_per_side_deg, included_angle_deg
- Diameters and length D is the large diameter, d the small, L the axial length over which the taper runs, all user-suppliedtaper geometry