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Geometry - Helix (Helicoid)
From Wikipedia:
"Helix A helix, plural helixes or helices, is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word helix comes from the Greek word ἕλιξ, "twisted, curved". (A "filled-in" helix – for example, a "spiral" ramp – is called a helicoid.)" DNA - single helical.jpg DNA - double DNA_double_helix-.jpg "Alpha Helix" https://en.wikipedia.org/wiki/Alpha_helix "Archimedes screw" shown in operation http://www.incois.gov.in/Tutor/scien...re10/screw.gif Auger auger.jpg HELICOID EJDYW0.jpg P1030993 copy.jpg CCDM2N.jpg Helicoid - Spiral stair: The designer developed his stair section, thus: Flighted substrate.jpg Made the shape into a heavy wood mock-up, maquette or "buck." 2X6 + 1in ply glued and screwed, then CNC milled in appropriate router-machine: AP1110691 copy.jpg And with some hammering here and there .... boom - whacka-whacka .... P1030882c.jpg
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. Last edited by crystallographic; 04-10-2020 at 05:43 PM. |
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