Twisted Sheet Metal Transformers first created 30/01/07 - last modified 08/2/07 Page Author: Ty Harness
One of my favorite sheet metal developments is the Hexagon-to-Hexagon twisted through 90 degrees with curved sides. I've never seen the development in a book although the triangulation technique is the same as Dickason's spiral finial [xx]. Grimsby College (Mr Ward who is still teaching) usually sets this problem for all Part 3 Sheet Metal students. Unfortunately these developments rarely crop up in a industrial application although I hope sheet metal workers who specialize in roofing still get the chance for to knock up some of the finer ornamental work.

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Figure 1a,b - Pattern development and Isometric of a hex to hex segment using the Mloft software


From the plan in 1a you can see the mitring angles but it would be practically impossible to cut those angles in a mitre box or vice for sheet metal. Although the job looks complex the flat panel development is simple using the triangulation method but note the length of each side must be the same length for the mitring to work.

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Figure 2 - A 3D DXF export from the Mould Loft application and rendered in Right Hemisphere's Deep Exploration


Of course a hexagon to hexagon is only one example and the beauty of turning the geometric development into algebra allows you to solve an infinity of problems. Figure 3 shows triangular, square, hexagon, octagon and a 12 sided polygon.

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Figure 3 - A selection of twisted finials with the DXF rendered in TurboCAD 10.5Pro.




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References {Please note I have no affiliation with any of the references below}
http://www.righthemisphere.com/
http://www.turbocad.com