John Carmichael asked: > >I have a commission to design a 5ft diameter horizontal mosaic dial for >the island of Bonaire in the Caribbean. Because of all the rain they get, >the client wants me to incline the dial face slightly (but not a lot) for >water drainage. > >How many degrees should I incline the dial? Is there some set standard >that builders use for things like sidewalk drainage?
As I recall the inner 5 metre radius of the Silverlink dial had a 1:30 drainage cast and the outer five metres 1:60 which raised all sorts of difficulties. The main problem was that the hourlines were rotated significantly from their theoretical position on a plane surface by their intersection with what had become a cone. I have a diagram somewhere which explains this if needed. It was for this reason that I set them out using a laser trigon made especially for the purpose....and never used since! :-( Tony Moss -
