Cone Flat Pattern

Calculate the 2D flat pattern required to roll a truncated cone (reducer, hopper, or funnel).

Used to calculate Neutral Axis dimensions.
Layout Dimensions
Inner Radius (R1)

0.00

in
Outer Radius (R2)

0.00

in
Sweep Angle ($\theta$)

0.0

°
Outer Chord Length: 0.00 in
Enter dimensions to preview
Layout Instructions
  1. Mark a center point on your sheet metal.
  2. Use trammel points (or a string) to scribe two arcs from the center: one at Inner Radius (R1) and one at Outer Radius (R2).
  3. Measure the Outer Chord Length across the outer arc to mark your start and end points, or use a protractor to mark the Sweep Angle.
  4. Draw straight lines from the center point through your arc marks to create the cut lines.
Neutral Axis Correction

If you provide a material thickness, this calculator assumes you entered the Outside Diameters and automatically subtracts the thickness to calculate the flat layout based on the Neutral Axis. This ensures the cone rolls perfectly to your desired OD.