Materials and components for the Assay Office Birmingham sculptural clock (see the complete design), ‘The Guardian’, have been arriving in the workshop during the past few months. My team and I have been cutting aluminium, finishing bronze and smoothing out the hiccups that inevitably occur in such a complex project.
Construction began by building a hydraulic winch on a movable frame, allowing us to assemble over 2100 clock components before installation. This framework allows us to rotate, lift and lower the 2 metre diameter structure and to access it from all sides as we build.
The main construction material of the external icosahedral structure is aluminium tube and rod. This arrived in 4 metre lengths which just fitted into a spare space on the workshop floor. My first job was cut these into varying, yet exact, lengths and angles to precisely fit together and form the structure… I needed 660 individual lengths and did my best to wear through the blade in the circular saw whilst cutting them.
Once cut and sorted into lengths the tubes were then carefully drilled to fit fastenings in a series of multi-armed bronze ‘nodes’. These ‘nodes’ will hold the piece together, providing structure for the outer body of the Guardian. Using a specially constructed, home-made jig in a pillar drill, my assistant Becca accurately drilled 780 holes in the aluminium tubes, each positioned to within 0.1mm….thank goodness she has perseverance!
Once she had worked through that pile of aluminium she began centre-drilling solid rods, using the lathe, to form the outer layer of the Guardian’s body. The piece is surrounded by a ‘cloud’ of rods that project from the structure and whose angled end-surfaces create the visually perfect spherical form of ‘The Guardian‘. Each differing length rod will be screwed from their inner end into the appropriate node at the correct angle. Another 270 drilled holes later, Becca cleaned and scoured the surface of the rods and tubes to a fine matt finish.
Meanwhile, the 130 bronze nodes which will connect the tubes together were being produced in the Jewellery Quarter using a combination of ancient and cutting-edge techniques. Using my hand-drawn designs translated into CAD by whizz-kid in engineering computer graphics, Adam Humphries, the casting patterns were 3D printed by the Jewellery Innovation Centre and then lost- wax cast by A.Wardle & Co.
The cast nodes arrived in the workshop with a nicely textured surface needing casting sprues and minor imperfections removed. Co-designer Wally Gilbert ably cut, sanded and finished each node ready for the test construction before final bead blasting, gold plating and lacquering.
The remotely-controlled electronic motors made by Smith of Derby that will drive the timepiece are hidden within the large aluminium sphere which is mounted centrally within the ‘Guardian’. This sphere was beautifully spun in two sections by Brazier Metal Spinners in Birmingham, arriving in the workshop like parts of a flying saucer from the 1950’s. I centred these on another specially made jig before drilling out the middle of each sphere in preparation for making the mounting boss for the clock mechanism’s ‘minute’ spindle.
The piece will be suspended from a stainless steel chassis which forms the core of the whole structure. This, along with the aluminium drives which rotate the printed acrylic ‘hour’ discs and dials, were cut and constructed using laser cutting and TIG welding by USM in Redditch.
USM took my technical diagrams and computer drawings and translated them into CAD. These were passed to a minibus-sized laser cutting machine and I watched entranced as powerful modern magic performed a laser light dance on metal, incising with astonishing accuracy the components that I had originally imagined during the year long technical design phase.
Further ‘magic’ has been performed by Daniel Wilmot of the University of Wolverhampton’s’ Faculty of Science and Engineering, who 3D printed the four crucial titanium support nodes.
Known for their involvement in the cutting edge motor racing industry, the University were the ideal choice for the manufacture of these one-off complex components from which the Guardian will be suspended. Generously funded by Cooksongold, Daniel proved equal to this unexpectedly challenging task through his invention of an innovative method of 3D printing that resulted in the jewel-like quality of the nodes.
Now it only remains for the ‘hour’ discs and dials to be printed, the final drive components and ‘minute’ rings to be machined and we’ll be armed with a full inventory of materials, processed and ready to begin the trial construction of The Guardian.
Once the trial is complete (and successful!) 1200 individual components will be coloured and finished ready for final assembly at Assay Office Birmingham. Watch out for the conclusion of this 4 1/2 year (to date) journey and the suspension of The Guardian into its permanent, iconic home at the new Assay Office Birmingham.