PRT - Tourbillon metals

Michael is one of the the lucky 100 to have the white gold (with 'white' hands) version. Another 100 and 100 lucky people have the chance to have the platinum and rose gold versions respectively over the coming year(s).

When I was reading the cover story article (Watch International, No 4, Dec 2007) in my garden with bright evening sunshine, my eyes were immediately drawn to the single common feature of all these watches (from the front view) - the tourbillon. Is it technically possible to make the tourbillon in the materials that would align aesthetically and in part "metallurgically" with the case material.

• Andrew

I don't believe matching metals are possible...

Hi Andrew,

Some of the parts of the tourbillon --like the balance ring itself-- need to be made of special metals (beryllium, copper, and iron , which is called berrylium bronze and trade-named Glucydur).

The rotating parts usually need to be made as light as possible. I know for several years IWC used titanium, but I think they now use a special steel. The problem is that platinum would be too heavy, and I suspect that IWC's white gold would also since it uses palladium. I guess in theory yellow gold could be used, but I know of one watch company that considers it too soft a metal for movement parts.

Regards,
Michael

merci (nt)

I would think any Gold is to soft for Tourbillon.

I would think any Gold is to soft for Tourbillon.

i think white os ok if it is hardened with other additives.
i'm pretty sure jlc use it in the gyrotourbillon

don't confuse gen'l movement vs. tourbillon-specific parts

JLC for its gyrotourbillon cage uses a special type of aluminum. The cage is supported by titanium parts. The lightness of the tourbillon is of paramount importance since the cage needs to revolve with relatively little use of power.

The balance wheel used inside the JLC gyrotourbillon cage reportedly is gold, but the wheel itself can be heavier (after all, in 99.9% of fine watches it is berylium bronze), since to my understanding that will create greater spinning inertia. I don't understand why gold was used since berylium bronze has better constancy to temperature fluctuation.

it is possible to make movement plates, bridges and cocks out of various metals, including golds. IWC of course plated its movements in gold from the late 1980s (as a quick guess without checking) to about 2002. The problem is that the gold, even with additives, scratches a little more easily. Platinum is too hard to machine, too costly and too heavy.

Regards,
Michael