Hi Dave. You are a mindreader. Your sliding gnomon mechanism is exactly what I had envisioned. The only change I considered would be to thread the bottom of the style so that it would be screwed into the sliding mechanism. That way it could be removed for transport, storage or replacement if damaged. The whole mechanism would be inlayed into the stone (or metal) dial face. I would engrave the date scale into the brass. But the more I think about it, I believe that I like the "chess piece" design better. But that's just my personal artistic preference. (I love the spiral legs.) I have a picture in my mind of a possible Tony Table-top metal analemmatic and it's beautiful! I think you could sell that.
John John L. Carmichael Jr. Sundial Sculptures 925 E. Foothills Dr. Tucson Arizona 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Website: <http://www.sundialsculptures.com> ----- Original Message ----- From: "Dave Bell" <[EMAIL PROTECTED]> To: "John Carmichael" <[EMAIL PROTECTED]> Cc: "Sundial List" <[email protected]> Sent: Thursday, October 24, 2002 1:52 PM Subject: Re: A New "That's Cool" Analemmatic > Beautiful, John!! A real piece of functional art... > > As I read your description, I also wondered why we haven't seen more small > analemmatic dials. It (now) seems like a perfectly natural idea! When you > mentioned having an attached, sliding gnomon, I had a vision of a > mechanical means of placing one. I wouldn't think it would be the ideal > plan for a stone dial like yours. On the other hand, it might be > appropriate for a metal instrument, like one of Tony Moss's brass > sculptures. > > Have the gnomon attached to a sliding block, running in a slot through the > dial face. Under the face, possibly within the thickness of the dial > plate, run a long-pitch leadscrew, to move the gnomon north and south. If > the leadscrew is cut with dual left- and right-hand threads, like a > "Yankee" screwdriver, continuous rotation (in either direction) will move > the carrier block out and back, linearly. Link a 12-month calendar dial > face and pointer to the screw, and you have a direct setting for the date. > Of course, a single thread screw would work also, but then you would have > to contend with stops and the operator would need to reverse the cranking > direction at the Solstices... > > Dave Bell > 37.28N 121.97W > 24 October 2002 > > - > -
