John Carmichael wrote (01 August 2003 16:12): <<Because of the importance of rod gnomon attachment on stained glass sundials and the interest in the subject, I thought I'd make a Delta Cad scale drawing for the website showing a sideview of the hardware used to attach it to a pane of glass, using the bolting method.>>
I should think that fixing a gnomon by just one attachment at its root would be problematic. For one thing it will be awkward to align accurately, but more importantly it will exert great leverage at the fixing point, and if the end is pushed by whatever means it will be far more likely to break the glass. Better to do what most of the old ones did and have a forked stay supporting the bottom end or the middle of the gnomon similarly fixed by nuts and washers into two more holes. That both assures rigidity and placement and ensures that very little strain is on any one of the fixing points, if properly fitted. It may be worth pointing this out to avoid short lived designs! Incidentally the outside of Bucklebury seems clearly to show the washer positions. Have you also considered the difference between drawing the hour lines on the inside and outside of the glass? The diagram shows the centre as outside, but if the paint is inside surely the gnomon root should pass through the dial centre on the inside surface, allowing also for refraction? Regards Andrew James -
