Sector Angle Formula:
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A truncated cone flat pattern is the 2D development of a conical frustum that can be rolled into a 3D truncated cone shape. The sector angle determines how much of a full circle is needed to create the pattern.
The calculator uses the sector angle formula:
Where:
Explanation: The formula calculates the angle needed to create the flat pattern that will form the truncated cone when rolled.
Details: Accurate sector angle calculation is crucial for sheet metal work, piping, and any application where a conical transition piece needs to be fabricated from flat material.
Tips: Enter all dimensions in consistent units (meters shown). The large radius must be greater than the small radius, and slant height must be positive.
Q1: What if my cone doesn't have a top (r=0)?
A: For a complete cone (no truncation), simply enter 0 for the small radius (r).
Q2: How do I measure slant height?
A: Slant height is the straight-line distance from the base to the top along the cone's side.
Q3: What units should I use?
A: The calculator works with any consistent units, but outputs will be in the same units you input.
Q4: Can I use this for very shallow cones?
A: Yes, but for very shallow cones (where R ≈ r), the pattern will be nearly flat.
Q5: How do I use the sector angle to make the pattern?
A: Draw two concentric circles with radii equal to your cone dimensions, then mark out the sector angle and cut.