Fabricating the harmonograph: detailing in brass
The beauty of a large structure is enhanced by attention to detail, and in the case of this harmonograph, the details are rendered in solid brass. Brass details invoke the wonderful scientific and pseudo-scientific contraptions of the nineteenth century and I was fortunate to have the support of a specialized metalwork technician, Ricky Lee Brawn, who has the skills to render these to perfection, and to teach me a few skills along the way.
The first thing that Ricky made was the magnificent brass finial that weights the whole structure down. Working on one of his fine vintage lathes, he spent several hours machining this to my design out of a piece of 3 inch diameter brass rod. I had to produce a very detailed drawing with measurements for every curve and blip. He also gave me an induction on the lathe – I got to shave down the base, and I got my introductory shower of golden swarf!
The lathes are so beautiful and complicated in an old-time machine sort of way, with their selection of precision cutting tools, massive chuck, and beautifully honed components – I have to post a dedicated picture of one:
Other details include the mirror mounted on the central pole of the harmonograph, The steel elements were forged and welded by Dave Stewart, and I hand gilded a piece of circular glass with palladium leaf to make the mirror. I chose palladium over silver
because it has a greyish tone, which works well with the blackened steel. Ricky showed me how to make the brass bezel – it took several days to hammer-form a sheet of 1mm brass to create this. The brass was first annealed with a blow torch to soften it – the heat causes microscopic changes to the structure on the surface of the metal, which results in the most amazing spectrum of colours.
Other details include the strips of 3mm brass with which I edged the table top, brass collars for the holes that are to take the pendulum mechanisms, and a second machined finial to sit atop the mirror column.
Time-consuming, expensive, but rewarding work. I feel immensely privileged to have had the opportunity to learn these processes from a master. Ricky Lee Brawn is a wonderful teacher, very disciplined, but with a warmth that makes you feel like a daughter!