iain wrote: ↑Fri May 26, 2023 7:53 am @richtel Thanks for that video, I have wondered how this effect was achieved. I suppose the challenge is getting the speeds of those two wheels exactly right so the brushed lines run straight.

I’d wondered about that too Iain. There would also need to be a bit of choreography between the workpiece rotation and the engagement and disengagement of the workpiece during spin up and spin down.

Friday 2 June

Meterorite dials. We've seen them on expensive luxury watches down to small microbrands- the distinctive and unique grey crystalline pattern usually engulfed in shovelfuls of 'out of this world' marketing hyperbole. But how are they made and what gives them the distinctive look?

A Meteorite, of course, is a piece of debris from a comet, asteroid or meteroid, probably starting life as a piece of molten planetary core billions of years ago and has been lying through space for many millions of years before finally sucomming to earth's gravity. A meteorite is a fragment that has survived falling through earth's atmosphere.

Mainly consisting of iron and nickel, as the debris cooled in the coldness of space the alloy slowly cooled to create the mix of crystallic features we recognise today. The patterns, often referred to as Widdmanstätten patterns after an Austrian scientist Count Alois von Beckh Widdmanstätten form an interleaving pattern of short and longer ribbons called kamacite and taenite which differ by their proportions of nickel content.

If carefully cleaved, polished and acid etched to draw out the visible crystal structure, they can be cut onto wafers for use on dials. They're difficult to work with being extremely brittle and potentially magnetic but each dial, by its very nature, will be totally unique.

One of the largest meterorites, the 4-billion year old Gibeon meteorite which fell on Namibia in prehistoric times measured some 4 metres across before shattering into many fragments. Pieces of the Gibeon meteorite have been used by many manufacturers, including Rolex. Namibia has now banned further meteorite collection, protecting them as national monuments.