Enter Cone Sheet Metal Details
Example Data Table
| Use Case | Large Diameter | Small Diameter | Height | Thickness | Typical Material |
|---|---|---|---|---|---|
| Duct transition | 600 mm | 300 mm | 450 mm | 2 mm | Mild steel |
| Hopper cone | 900 mm | 150 mm | 700 mm | 3 mm | Stainless steel |
| Decorative cone | 400 mm | 0 mm | 650 mm | 1 mm | Aluminum |
Formula Used
This calculator uses standard cone and frustum layout formulas.
Radius large end = D / 2
Radius small end = d / 2
Slant height = √(height² + (R - r)²)
Lateral area = π × (R + r) × slant height
Outer pattern radius = R × slant height / (R - r)
Inner pattern radius = r × slant height / (R - r)
Sector angle = 360 × (R - r) / slant height
Blank area = lateral area + allowance area
Blank area with waste = blank area × (1 + waste% / 100)
Weight = area in m² × thickness in m × density
Total cost = material weight × cost per kg + labor cost
How to Use This Calculator
Choose the cone type first. Select a frustum for a cone with two open ends. Select a full cone when the small end closes to a point.
Enter the large diameter, small diameter, and vertical height. Use the same length unit for all size inputs. Add sheet thickness, density, seam allowance, edge allowance, waste, cost, and quantity.
Press the calculate button. The result panel appears above the form and below the header. Review the slant height, sector angle, blank area, weight, and cost. Use the chart to compare main fabrication values. Export the result using CSV or PDF.
Sheet Metal Cone Layout Guide
Why cone development matters
Sheet metal cones are common in ducts, hoppers, funnels, guards, reducers, and industrial transitions. A correct cone pattern saves material and prevents shop errors. The flat blank must match the final rolled shape. Small layout errors can create poor seams. They can also cause wrong end diameters after rolling.
Important measurements
The main inputs are large diameter, small diameter, and vertical height. These values define the true cone shape. The slant height gives the real side length. It is not the same as vertical height. The blank is drawn as a circular sector. A frustum uses two arcs. A full cone uses one outer arc and one center point.
Allowances and waste
Fabrication rarely uses pure geometry alone. The sheet needs a seam allowance for joining. It may also need edge allowance for trimming, folding, welding, or forming. Waste percentage covers handling loss, cutting kerf, nesting gaps, and trial cuts. A higher waste value is useful for thick plates and difficult materials.
Weight and cost planning
Weight is based on developed area, sheet thickness, and material density. Mild steel often uses a density near 7850 kg per cubic meter. Aluminum and stainless steel need different density values. The cost estimate multiplies total weight by material cost. Labor cost can be added for a fuller production estimate.
Practical fabrication notes
Always check your shop process before cutting. Rolling machines, weld gaps, edge preparation, and bend behavior can change the final fit. Mark the sector angle carefully. Check both arc lengths. Use test pieces when the cone is expensive or critical. This tool gives a strong planning estimate. Final templates should follow your workshop standards and material behavior.
Frequently Asked Questions
What is a cone sheet metal pattern?
It is the flat sector shape cut from sheet metal. After rolling, it forms a cone or frustum with the required diameters and height.
What is slant height?
Slant height is the true side length of the cone. It runs from one circular edge to the other along the cone surface.
Why is sector angle important?
The sector angle controls how much of the circular pattern is used. A wrong angle changes the final diameter after rolling.
Can this calculator handle full cones?
Yes. Select the full cone option. The calculator sets the small diameter to zero and calculates a single-point cone layout.
What density should I use for steel?
Mild steel is often estimated at 7850 kg/m³. Use your supplier value when precision weight or cost is important.
What does seam allowance mean?
Seam allowance is extra sheet added for welding, riveting, locking, or overlapping the joint. It helps create a usable connection.
Why add waste percentage?
Waste covers cutting kerf, nesting gaps, trimming, trial pieces, and handling loss. It gives a safer material estimate.
Is the result ready for final cutting?
Use it as a planning and layout estimate. Confirm allowances, rolling behavior, and shop standards before cutting costly material.