An quick and easy way to make a helical dial for demonstration and experimental purposes is to take a wide strip of dressmaking elastic, with a whole twist, held on a frame which can be made for example by bending a wire coathanger. The hours can be marked in ink at equal intervals while it's flat. This isn't my own idea but I can't remember whose it was - so I offer apologies and credit wherever it is due.
Regards Andrew James 51 04' N 1 18' W -----Original Message----- From: Frans W. Maes [mailto:[EMAIL PROTECTED] Sent: 01 December 2003 11:34 To: sundial@rrz.uni-koeln.de Subject: Re: Dial design Hi Richard, It seems you have reinvented Piet Hein's helical dial. See the home page of Egeskov Castle, http://www.egeskov.dk/english/sightseeing/index.htm and click nr. 25 on the map or in the list below it. John Moir showed already that the dial does not function well outside the equinoxes in BSS Bulletin 95.1. I give an explanation of this ill-behavior in my website: www.fransmaes.nl/sundials, choose Index and goto Kvaerndrup. Regards, Frans Maes 53.1N 6.5E ----- Original Message ----- From: "Richard Hollands" <[EMAIL PROTECTED]> To: <sundial@rrz.uni-koeln.de> Sent: 30 November, 2003 6:34 PM Subject: RE: Dial design I've just realized, thinking about it again, that the simplest realization of a 'helical' dial is a single sheet of metal given a half-twist of 180 degrees. So long as the edges are straight and the twist is distributed uniformly then the desired "line o'light" effect will be achieved. -
