The Harry Winston’s “Histoire de Tourbillon” is the fourth such piece in a series that began in 2009. The main feature of the watch is an interesting tri-axial tourbillon positioned at 6 o’clock — envision a tourbillon cage fitted inside a tourbillon cage fitted inside a tourbillon cage, each rotating at different rates per minute. The Histoire de Tourbillon 4 will be limited to just 20 pieces.
The Histoire de Tourbillon 4 has a cushion-shaped case measuring approximately 47mm square. It is a mix of white gold and Zalium, Harry Winston’s proprietary alloy, and one that they use in many of their timepieces. You can see the white gold on the top of the case, for example (mirror polished). The Zalium, DLC-treated, is used for the case band, arches, lugs and tourbillon bezel. You can see it has a matte, brushed finish to it. The caseback is partially open, again in a mix of DLC-finished Zalium and white gold. The crown is white gold, with rubber grip.
The three-dimensional dial displays hours, minutes, power reserve and also interestingly there is a 300-second indicator on the tourbillon. The triple tourbillon sites under a domed sapphire crystal at 6 o’clock. The thickness of the watch including the dome is 21.7mm.
The Caliber HW4501 is a 345-component, manual-wind mechanical movement with tri-axial tourbillon. It has two barrels which support a power reserve of 50 hours. The caliber a very substantial 40mm in diameter and 17.3mm thick. The tourbillon has 134 components. The innermost tourbillon rotates once every 45 seconds; the intermediate tourbillon rotates once every 75 seconds; the outermost tourbillon rotates once every 300 seconds. The tourbillon components are made of both PVD-finished titanium and gold. The intermediate tourbillon cage is polished gold and also chamfered. The main plate of the movement is titanium with a micro-blasted finish; the bridges are PVD-finished and chamfered by hand.